WO2016161941A1 - Bio-blocs comprenant des cellules endothéliales et leurs procédés d'utilisation - Google Patents

Bio-blocs comprenant des cellules endothéliales et leurs procédés d'utilisation Download PDF

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Publication number
WO2016161941A1
WO2016161941A1 PCT/CN2016/078638 CN2016078638W WO2016161941A1 WO 2016161941 A1 WO2016161941 A1 WO 2016161941A1 CN 2016078638 W CN2016078638 W CN 2016078638W WO 2016161941 A1 WO2016161941 A1 WO 2016161941A1
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bio
block
shell
cell
core
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PCT/CN2016/078638
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English (en)
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Yujian James KANG
Xiao ZUO
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Sichuan Revotek Co., Ltd.
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Publication of WO2016161941A1 publication Critical patent/WO2016161941A1/fr

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
    • A61L27/50—Materials characterised by their function or physical properties, e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
    • A61L27/58—Materials at least partially resorbable by the body
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
    • A61L27/14—Macromolecular materials
    • A61L27/22—Polypeptides or derivatives thereof, e.g. degradation products
    • A61L27/24—Collagen
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
    • A61L27/36—Materials for grafts or prostheses or for coating grafts or prostheses containing ingredients of undetermined constitution or reaction products thereof, e.g. transplant tissue, natural bone, extracellular matrix
    • A61L27/38—Materials for grafts or prostheses or for coating grafts or prostheses containing ingredients of undetermined constitution or reaction products thereof, e.g. transplant tissue, natural bone, extracellular matrix containing added animal cells
    • A61L27/3804—Materials for grafts or prostheses or for coating grafts or prostheses containing ingredients of undetermined constitution or reaction products thereof, e.g. transplant tissue, natural bone, extracellular matrix containing added animal cells characterised by specific cells or progenitors thereof, e.g. fibroblasts, connective tissue cells, kidney cells
    • A61L27/3808—Endothelial cells
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
    • A61L27/36—Materials for grafts or prostheses or for coating grafts or prostheses containing ingredients of undetermined constitution or reaction products thereof, e.g. transplant tissue, natural bone, extracellular matrix
    • A61L27/38—Materials for grafts or prostheses or for coating grafts or prostheses containing ingredients of undetermined constitution or reaction products thereof, e.g. transplant tissue, natural bone, extracellular matrix containing added animal cells
    • A61L27/3804—Materials for grafts or prostheses or for coating grafts or prostheses containing ingredients of undetermined constitution or reaction products thereof, e.g. transplant tissue, natural bone, extracellular matrix containing added animal cells characterised by specific cells or progenitors thereof, e.g. fibroblasts, connective tissue cells, kidney cells
    • A61L27/3826—Muscle cells, e.g. smooth muscle cells
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
    • A61L27/36—Materials for grafts or prostheses or for coating grafts or prostheses containing ingredients of undetermined constitution or reaction products thereof, e.g. transplant tissue, natural bone, extracellular matrix
    • A61L27/38—Materials for grafts or prostheses or for coating grafts or prostheses containing ingredients of undetermined constitution or reaction products thereof, e.g. transplant tissue, natural bone, extracellular matrix containing added animal cells
    • A61L27/3804—Materials for grafts or prostheses or for coating grafts or prostheses containing ingredients of undetermined constitution or reaction products thereof, e.g. transplant tissue, natural bone, extracellular matrix containing added animal cells characterised by specific cells or progenitors thereof, e.g. fibroblasts, connective tissue cells, kidney cells
    • A61L27/3834—Cells able to produce different cell types, e.g. hematopoietic stem cells, mesenchymal stem cells, marrow stromal cells, embryonic stem cells
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
    • A61L27/50—Materials characterised by their function or physical properties, e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
    • A61L27/54—Biologically active materials, e.g. therapeutic substances

Definitions

  • the present invention relates to the field of biology, regenerative medicine, bioprinting (such as cell-based three dimensional (3D) bioprinting) , and tissue engineering.
  • bioprinting such as cell-based three dimensional (3D) bioprinting
  • tissue engineering such as cell-based three dimensional (3D) bioprinting
  • the present invention relates to bio-blocks comprising endothelial cells and use thereof for preparing artificial tissues having a microvascular network.
  • Human tissues are composed of cells arranged in an orderly manner. Tissues and cells with different physiological functions are usually associated with distinct cellular distribution patterns. For example, epithelial cells are tightly packed as a monolayer to ensure their protective functions. Muscle cells are arranged in a cord-like structure to support their contractile function. Neurons either remain parallel to each other, or interconnect with each other to form a web-like structure to facilitate their function of information delivery.
  • Abnormalities in cell distribution are manifested as defects in cell morphology, intercellular connections, and/or activities of the cell group. Abnormal cellular distribution patterns commonly arise during pathological transformations of tissues and organs, leading to functional defects of cells and damaging the overall structure and functions of the tissues and organs.
  • hepatic cords in a hepatic tumor tissue are disarranged and lack the lobule structure of a normal liver.
  • Disorder in distribution of epithelial cells of the small intestine compromises the protective functions of the epithelial barrier, leading to increasing levels of endotoxins absorbed through the small intestine, and ultimately causing endotoxemia.
  • Irregular distribution of vascular smooth muscle cells reduces compliance, elasticity and anti-strain capacity of blood vessels. Therefore, precision distribution of cells is a key factor in artificial tissue and organ construction.
  • bioprinting a vascularized artificial tissue has been a major challenge in the field.
  • the blood capillaries are the only routes for cells in deep tissues to get nutrition and discharge metabolites. It is thus critical for the bioprinted artificial tissues to have blood capillaries in order to connect to the main blood vessels to ensure cell survival.
  • many 3D bioprinted tissues have limited thickness because they quickly develop necrotic regions without perfusable vasculature within a few hundred microns of each cell.
  • Methods have been developed to embed vasculature in bioprinted tissues using sacrificial or fugitive inks that can be removed to create synthetic microvascular networks. See, for example, Kolesky, David B., et al.
  • Bio-blocks are cell-based building blocks with a core-shell structure comprising biodegradable polymeric materials that provide mechanical protection and microenvironments for the cell that is embedded in or enwrapped by the core.
  • bio-blocks are particularly useful for construction of multi-dimensional biological structures having precise cell distribution patterns. See, for example, International Patent Application No. PCT/CN2015/075967, and International Patent Application No. PCT/CN2015/092549.
  • bio-blocks having cores comprising endothelial cells and optionally stem cells. Further provided are methods of preparing the bio-blocks, compositions comprising the bio-blocks (such as bio-ink compositions) , methods of bioprinting an artificial tissue or tissue progenitor using the bio-ink compositions, and other methods of using the bio-blocks or the compositions.
  • bio-block comprising: a) a core comprising a biodegradable polymeric core material, and an endothelial cell; and b) a shell comprising a biodegradable polymeric shell material.
  • the bio-block further comprises a stem cell.
  • a bio-block comprising: a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell; and b) a shell comprising a biodegradable polymeric shell material.
  • the stem cell is a mesenchymal stem cell (MSC) , such as a bone marrow-derived MSC, or an adipose-derived MSC.
  • MSC mesenchymal stem cell
  • the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20, such as at least about any of 1: 15, 1: 10, or 1: 5, or about 1: 20 to about 2: 3.
  • the bio-block (such as the core) further comprises a tissue specific cell.
  • the tissue-specific cell is a hepatocyte.
  • the tissue-specific cell is a smooth muscle cell.
  • the biodegradable polymeric core material comprises type I collagen.
  • the weight percentage of type I collagen in the biodegradable polymeric core material is at least about 0.4% (w/w) .
  • the core comprises an agent selected from a nutrient, an extracellular matrix factor, a cell factor, and a pharmaceutically active agent. In some embodiments, the core comprises at least 3 different agents. In some embodiments, the core comprises a cell factor that facilitates cell proliferation, and the cell factor is selected from the group consisting of insulin, IGF-I, IGF-II, TGF, VEGF, PDGF, ODGF, SRIH, NGF, EGF, FGF, IL-1, IL-2, IL-3, IL-4, IL-5, IL6, IL-7, IL-8, IL-10, IL-12, CCL, CXC, XCL, MCP, TNF, EPO, CSF, cortisol, T3, T4, and combinations thereof.
  • the core comprises a cell factor that facilitates cell differentiation, and the cell factor is selected from the group consisting of Oct3/4, Sox2, Klf4, c-Myc, GATA4, TSP1, ⁇ -glycerophosphate, dexamethasone, vitamin C, insulin, IBMX, indomethacin, PDGF-BB, 5-azacytidine, and combinations thereof.
  • the core comprises a cell factor that facilitates cell migration, and the cell factor is selected from the group consisting of cAMP, PIP 3 , SDF-1, N-cadherin, NF- ⁇ B, osteonectin, thromboxane A2, Ras, and combinations thereof.
  • the core comprises a cell factor that facilitates cell metabolism
  • the cell factor is selected from the group consisting of IGF-I, TRIP-Br2, DKK-1, sRANKL, OPG, TRACP-5b, ALP, SIRT1, PGC-1 ⁇ , PGC-1 ⁇ , IL-3, IL-4, IL6, TGF- ⁇ , PGE2, G-CSF, TNF ⁇ , and combinations thereof.
  • the core comprises a cell factor that facilitates cell secretion, and the cell factor is selected from the group consisting of P600, P110, TCGFIII, BSF-2, glucagon, ⁇ -adrenergic agonist, arginine, Ca 2+ , acetyl choline, somatostatin, and combinations thereof.
  • the core comprises a pharmaceutically active agent, and the pharmaceutically active agent is selected from the group consisting of rhIL-2, rhIL-11, rhEPO, IFN- ⁇ , IFN- ⁇ , IFN- ⁇ , G-CSF, GM-CSF, rHuEPO, sTNF-R1, rhTNF- ⁇ , and combinations thereof.
  • the biodegradable polymeric shell material comprises polylysine. In some embodiments, the weight percentage of polylysine in the biodegradable polymeric shell material is at least about 1% (w/w) . In some embodiments, the biodegradable polymeric shell material comprises oxidized alginate or alginate. In some embodiments, the oxidation level of the oxidized alginate is about 1%to about 40%. In some embodiments, the biodegradable polymeric shell material comprises at least about 4%oxidized alginate or alginate (w/w) . In some embodiments, the biodegradable polymeric shell material comprises a mixture of alginate and oxidized alginate. In some embodiments, the ratio between the alginate and oxidized alginate is about 1: 9 to about 9: 1.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm.
  • the width of the bio-block is about 30 ⁇ m to about 2 mm.
  • the thickness of the bio-block is about 30 ⁇ m to about 2 mm.
  • the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) .
  • the bio-block comprises at least two cores.
  • the shell is permeable to nutrients. In some embodiments, the shell is permeable to a macromolecule having a molecular weight of at least about 110 kDa.
  • the shell comprises one or more micropores.
  • the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) .
  • the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa.
  • the bio-block comprises at least two shells.
  • the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa.
  • bio-ink composition comprising a plurality of any one of the bio-blocks described above.
  • the bio-ink composition further comprises a carrier.
  • the plurality of bio-blocks is suspended homogenously within the carrier.
  • the carrier is a liquid or a paste.
  • the carrier comprises a polymer selected from the group consisting of collagen, fibrin, chitosan, alginate, starch, hyaluronic acid, laminin, agarose, gelatin, glucan, elastin, methylcellulose, polyvinyl alcohol, polyamino acid (such as polylysine) , acrylate copolymer, and combinations thereof.
  • the carrier has a viscosity of about 1 Pa ⁇ s to about 1000 Pa ⁇ s.
  • the bio-ink composition comprises at least about 50%bio-blocks (w/w) .
  • bioprinting any one of the bio-ink compositions described above to obtain a multi-dimensional construct having a pre-determined pattern.
  • the bio-ink composition is not bioprinted onto a scaffold.
  • the method further comprises culturing the multi-dimensional construct in vitro under a condition that allows the endothelial cell, the stem cell, and/or optionally the tissue-specific cell in the plurality of bio-blocks to proliferate, differentiate, metabolize, migrate, secrete, or any combination thereof.
  • the shell is at least partially degraded during the culturing.
  • an artificial tissue or a tissue progenitor prepared by any one of the methods described above.
  • the artificial tissue or tissue progenitor has one or more blood capillaries.
  • the length of the artificial tissue or tissue progenitor is at least about 500 ⁇ m.
  • the thickness of the artificial tissue or tissue progenitor is at least about 500 ⁇ m.
  • the endothelial cell, the stem cell, and/or optionally the tissue-specific cell in the bio-blocks proliferate, differentiate, migrate, or any combination thereof, and optionally wherein the biodegradable polymeric core material is at least partially degraded.
  • the endothelial cell, the stem cell, and/or optionally the tissue-specific cell in different bio-blocks are connected to each other, and wherein the biodegradable polymeric core material and/or the biodegradable polymeric shell material are at least partially degraded.
  • kits, and articles of manufacture comprising any one of the bio-blocks, the compositions (such as the pharmaceutical compositions or the bio-ink compositions) , the pluralities of bio-blocks, the multi-dimensional constructs (such as composite constructs) , the tissue progenitors, or the artificial tissues described above.
  • FIG. 1A shows an exemplary bio-block, including a schematic cartoon in the left panel, and an image of a bio-block in the right panel.
  • the core comprises three cells enwrapped by a biodegradable polymeric core material, and the shell is has microchannels or micropores for exchange of materials, such as nutrients.
  • FIG. 1B depicts an exemplary bio-block structure having a single shell and a single core, wherein the shell coats the core.
  • FIG. 1C depicts an exemplary bio-block structure having a single core coated by a first shell, and the first shell coated by a second shell.
  • FIG. 1D depicts an exemplary bio-block structure having a first core coated by a second core, and the second core coated by a single shell.
  • FIG. 1E depicts an exemplary bio-block structure having a first core coated by a second core, the second core coated by a first shell, and the first shell coated by a second shell.
  • FIG. 1F depicts an exemplary bio-block structure having a first core coated by a first shell, the first shell coated by a second core, and the second core coated by a second shell.
  • FIGs. 2A-2F depict exemplary spherical bio-blocks with different sizes and different number of cells under phase contrast microscopy.
  • the bright outer circles are the shells of the bio-blocks, and the bright spots inside the large circles are the HUVECs in the cores.
  • FIG. 2A shows bio-blocks with a size of 120 ⁇ m.
  • FIG. 2B shows bio-blocks with a size of 200 ⁇ m.
  • FIG. 2C shows bio-blocks with a size of 450 ⁇ m.
  • FIG. 2D shows bio-blocks, each with about 50 cells.
  • FIG. 2E shows bio-blocks, each with about 8 cells.
  • FIG. 2F shows bio-blocks, each with about 2 cells.
  • FIG. 3 depicts an exemplary bio-block under phase contrast microscopy.
  • One spherical bio-block is shown in the middle of the view.
  • the bright outer circle is the shell of the bio-block, and the bright spots inside are the Human Umbilical Vein Endothelial Cells (HUVECs) in the core.
  • UUVECs Human Umbilical Vein Endothelial Cells
  • FIGs. 4A-4F depict bio-blocks of various combinations of polymeric core materials and polymeric shell materials. Scale bar of all figures are 500 ⁇ m, unless otherwise stated. Thin white arrows designate locations of shells, and thick white arrows designate locations of cores.
  • FIG. 4A shows bio-blocks with a shell comprising calcium alginate and a core comprising starch.
  • FIG. 4B shows bio-blocks with a shell comprising polylysine and a core comprising type I collagen.
  • FIG. 4C shows bio-blocks with a shell comprising calcium alginate and a core comprising type I collagen.
  • FIG. 4D shows bio-blocks with a shell comprising calcium alginate and a core comprising polyurethane.
  • FIG. 4E shows a bio-block with a shell comprising polylysine-FITC and a core comprising type I collagen stained with tracker CM-Dil (read fluorescence) .
  • FIGs. 5A-5B depict an exemplary bio-ink composition for bioprinting.
  • FIG. 5A shows a bio-ink composition comprising a carrier and a plurality of bio-blocks. The dark bio-block further comprises methyl violet in the core to demonstrate integrity of the bio-block after bioprinting.
  • FIG. 5B shows a bioprinted bio-block monolayer with a width of about 250 ⁇ m. Shown in the figure is one bio-block surrounded by the carrier, which also serves as a biocompatible (optionally bioadhesive) material to bind the bio-block. The bio-block maintained the structural integrity after bioprinting.
  • FIG. 6 depicts a plot of viscosity in mPa ⁇ s of a carrier comprising sodium alginate and gelatin in an exemplary bio-ink composition as a function of temperature.
  • FIGs. 7A-7D depict survival of Human Umbilical Vein Endothelial Cells (HUVECs) in bio-blocks.
  • FIG. 7A shows HUVECs in bio-blocks immediately after the bio-blocks were prepared. Each large circle shows approximately the boundary of a bio-block.
  • FIG. 7B shows HUVECs in bio-blocks after storage at 4°C for about 3 hours after preparation. Each large circle shows approximately the boundary of a bio-block.
  • FIG. 7C shows HUVECs in bio-blocks after bioprinting. The white spots with high saturation level, such as the white spot pointed by a white arrow, are dead cells.
  • FIG. 7D shows HUVECs in bio-blocks after culturing at about 37°C for about 72 hours after preparation. The white spots with high saturation level, such as the white spot pointed by a white arrow, are dead cells. Images were collected using laser scanning confocal microscopy.
  • FIGs. 8A-8B depict adhesion and spreading of HepG2 cells inside bio-blocks.
  • FIG. 8A shows HepG2 cells (dark circular spots) inside multiple bio-blocks (large gray circles) on day one of culturing. Cells adopted a circular shape, and did not spread or adhere to other cells. The image was collected under 40 times magnification by phase contrast microscopy.
  • FIG. 8B shows HepG2 cells in a single bio-block on day 5 of culturing. White arrows point to spreading and adherent cells. The image was collected under 200 times magnification by phase contrast microscopy.
  • FIG. 9 depicts proliferation of HepG2 cells inside bio-blocks that had been cultured at about 37°C for about 5 days after preparation of the bio-blocks.
  • Cell nuclei were stained by DAPI (blue channel)
  • proliferating cells were stained using EdU (red channel) .
  • Cells in gray are proliferating HepG2 cells stained by EdU.
  • the image was collected under 200 times magnification using confocal scanning microscopy.
  • FIGs. 10A-10D show proliferation of cells inside traditional cell capsules or bio-blocks.
  • FIG. 10A shows cells in capsules immediately after preparation.
  • FIG. 10B shows cells in capsules after culturing for 7 days.
  • FIG. 10C shows cells in bio-blocks immediately after preparation.
  • FIG. 10D shows cells in bio-blocks after culturing for 7 days.
  • FIGs. 11A-11C depict connections among cells across the boundaries of different bio-blocks. All bio-blocks contain HepG2 cells and HUVEC cells.
  • FIG. 11A shows connections among cells of different bio-blocks marked by white circles.
  • FIG. 11B shows connections among cells across the border (marked with an arrow) between two bio-blocks.
  • FIG. 11C shows connections (yellow signal) between HepG2 cells (green) and HUVEC cells (red) across different bio-blocks.
  • FIG. 12A and FIG. 12B are pictures of Revotek B series 3D bioprinters.
  • FIG. 12C (side view) and 12D (top view) are ring-shaped three-dimensional structures printed using a bio-ink comprising 2%sodium alginate (left panels) , using a bio-ink comprising 5%sodium alginate (middle panels) , or using a bio-ink comprising 2%sodium alginate and bio-blocks.
  • the bio-ink containing bio-blocks had better mechanical support capacity to form tissues compared to other kinds of hydrogel.
  • FIGs. 13A-13I depict biological properties of bio-blocks.
  • FIGs. 13A-13D show cell viability in bio-blocks. Living cells were labeled with Calcein AM showing green fluorescence, and dead cells were labeled with propidium iodide showing red fluorescence.
  • FIG. 13A shows HUVECs in a bio-block immediately after the bio-block was prepared. Cell viability was more than 95%.
  • FIG. 13B shows HUVECs in bio-blocks after bioprinting. Cell viability was more than 90%.
  • FIG. 13C shows HUVECs in a bio-block after culturing at about 37°C with 5%CO 2 for about 5 days after preparation. Cell viability was more than 90%.
  • FIG. 13A-13D show cell viability in bio-blocks. Living cells were labeled with Calcein AM showing green fluorescence, and dead cells were labeled with propidium iodide showing red fluorescence.
  • FIG. 13A shows HUVECs in
  • FIG. 13D shows HUVECs in a bio-block after storage at 4°C for 3 h (left panel) , 24 h (middle panel) and 48 h (right panel) . Cell viability was more than 90%, 80%and 50%, respectively.
  • FIGs. 13E-13I show cells engaged in normal functions inside bio-blocks.
  • FIG. 13E depicts adhesion and spreading of HUVEC cells inside a bio-block.
  • FIG. 13F depicts proliferation of HepG2 cells inside a bio-block that had been cultured at about 37 °C for about 2 days after preparation of the bio-block. Cell nuclei were stained by DAPI (blue channel) , and proliferating cells were stained using EdU (red channel) .
  • FIG. 13G shows hepatocytes secreting albumin in bio-blocks.
  • Cell nuclei were stained by DAPI (blue channel)
  • albumin secreted by hepatocytes was stained by albumin test kit (red channel) .
  • FIG. 13H shows connections among cells inside bio-blocks.
  • HUVECs were labeled with cell tracker Green CMFDA showing green fluorescence (left panel)
  • HepG2 labeled with cell tracker CM-Dil showing red fluorescence (middle panel) .
  • Yellow fluorescence in right panel indicates cell connection between HepG2 and HUVEC.
  • FIG. 13I shows BMSC migration in bio-blocks. Arrows indicate the migrated cells.
  • FIGs. 14A-14D show degradation of bio-block shells and fusion of bio-blocks.
  • FIG. 14A shows a bio-block comprising a polylysine shell and HUVECs. Polylysine was labeled with FITC showing green fluorescence. HUVECs labeled with cell tracker CM-Dil showing red fluorescence.
  • FIG. 14B shows degradation of a bio-block shell using 0.25%trypsin. The shell was degraded partially in 5 min (middle panel) , and degraded completely in 10 min (right panel) .
  • FIG. 14C shows degradation of a bio-block shell. The shell of the bio-block was partially degraded by the cells in 5 days (middle panel) , and completely degraded in 9 days (right panel) .
  • FIG. 14D shows fusion of bio-blocks via cell connection after shell degeneration over time.
  • FIGs. 15A-15I show cartoon schematic of 3D bioprinting by a REVOTEK B series 3D bioprinter.
  • FIG. 15A shows a REVOTEK B series 3D bioprinter.
  • FIG. 15B shows a bio-block mixed with sodium alginate to be extruded by jet.
  • FIGs. 15C-15F show the shapes of various printed three-dimensional structure.
  • FIG. 15C shows a sheet structure formed by one type of bio-blocks.
  • FIG. 15D shows a sheet structure formed by two types of bio-blocks.
  • FIG. 15E shows a ring-shaped structure formed by two types of bio-blocks.
  • FIG. 15F shows an irregular-shaped structure formed by two types of bio-blocks.
  • FIGs. 15G-15I show accurate distribution of cells in bio-blocks. One type of cells expressed green fluorescence protein. A second type of cells expressed red fluorescence protein.
  • FIGs. 16A-16J shows that bio-blocks fused into an organic whole to form a tissue-like structure.
  • FIG. 16A shows bio-blocks comprising HepG2 cells labeled with cell tracker Green CMFDA showing green fluorescence.
  • FIG. 16B shows bio-blocks comprising BMSCs labeled with cell tracker CM-Dil showing red fluorescence.
  • FIG. 16C shows that the bio-blocks fused with each other after being cultured at 37°C with 5%CO 2 in H-DMEM media containing about 10%FBS for 3 days.
  • FIG. 16D shows that the bio-blocks fused into a single entity after being cultured at 37°C with 5%CO 2 in H-DMEM media containing about 10%FBS for 9 days.
  • FIG. 16E shows that the bio-blocks fused into a sheet-shaped artificial tissue. Thin arrows designate locations of connection between the two types of bio-blocks.
  • FIG. 16F shows HE staining of the sheet-shaped artificial tissue.
  • FIG. 16G shows that the bio-blocks fused into a ring-shaped artificial tissue.
  • FIG. 16H shows HE staining of the ring-shaped artificial tissue.
  • FIG. 16I shows that the bio-blocks fused into an irregular-shaped artificial tissue.
  • FIG. 16J shows HE staining of the irregular-shaped artificial tissue.
  • FIG. 17A shows a schematic cross-section layout of an exemplary tissue comprising two types of MSC bio-blocks.
  • FIG. 17B shows immunohistochemical staining results of the exemplary artificial tissue prepared by bioprinting two types of MSC bio-blocks.
  • FIG. 18 shows HE staining results (top panel) and immunohistochemical staining results against albumin (bottom panel) of an exemplary artificial liver tissue bioprinted using bio-blocks comprising adipose-derived MSC.
  • FIG. 19 shows anti-CD31 immunostaining results of a slice of an exemplary artificial tissue having a large number of blood capillaries.
  • FIGs. 20A-20F show formation of blood capillaries in artificial tissues bioprinted using bio-blocks comprising various types and ratios of cells. Black arrows point to examples of blood capillaries in the artificial tissues.
  • FIG. 20A shows formation of a small number of blood capillaries in an artificial tissue bioprinted using bio-blocks comprising a mixture of BMSC and HUVEC at a ratio of 20: 1.
  • FIG. 20B shows formation of a large number of blood capillaries in an artificial tissue bioprinted using bio-blocks comprising a mixture of BMSC and HUVEC at a ratio of 10: 1.
  • FIG. 20C shows formation of a small number of blood capillaries in an artificial tissue bioprinted using bio-blocks comprising a mixture of BMSC and HUVEC at a ratio of 3: 1.
  • FIG. 20D shows formation of a small number of blood capillaries in an artificial tissue bioprinted using bio-blocks comprising a mixture of BMSC and HUVEC at a ratio of 3: 2.
  • FIG. 20E shows formation of a large number of blood capillaries in an artificial tissue bioprinted using bio-blocks comprising a mixture of BMSC, hepatocyte, and HUVEC at a ratio of 10: 1: 1.
  • FIG. 20F shows formation of a small number of blood capillaries in an artificial tissue bioprinted using bio-blocks comprising a mixture of BMSC, smooth muscle cells, and HUVEC at a ratio of 16: 3: 1.
  • FIG. 20G shows formation of a small number of blood capillaries in an artificial tissue bioprinted using bio-blocks comprising a mixture of human MSC and HUVEC at a ratio of 3: 1.
  • the present application discloses a bio-block comprising one or more endothelial cells and optionally one or more stem cells (such as mesenchymal stem cells) in the core.
  • stem cells such as mesenchymal stem cells
  • inventive tissues or constructs bioprinted using the bio-blocks of the present application yielded microvascular networks in the artificial tissues or constructs.
  • the number of blood capillaries in the microvascular networks of the bioprinted artificial tissues or constructs depends on the types of cells and the ratio between the number of endothelial cells and the number of stem cells in the bio-blocks.
  • tissue-specific cells may be included in the bio-blocks, which may be used to bioprint vascularized artificial tissues or progenitors having the tissue-specific cells.
  • the ability to form internal microvascular networks is a key condition for preparing functional artificial tissues with large dimensions (such as thickness) that are useful for research and clinical use.
  • the bio-blocks, as well as the artificial tissues and the tissue progenitors comprising the bio-blocks or prepared by bioprinting of the bio-blocks and the bio-ink compositions disclosed herein are useful for a variety of applications in research and medicine, including tissue engineering, in vitro research, stem cell differentiation, in vivo research, drug screening, drug discovery, tissue regeneration, and regenerative medicine.
  • Embodiments of the bio-blocks described herein may have one or more technical advantages including, but not limited to:
  • the endothelial cells and optionally the stem cells in the core can give rise to blood capillaries in the artificial tissues prepared using the bio-blocks.
  • the blood capillaries transport nutrients to cells and remove waste from cells, thereby ensuring viability of cells inside the artificial tissues, and promoting biological functions of the artificial tissues;
  • the core comprises a controllable number, types, and ratios of cells, which is suitable as a standardized, controllable bioprinting material;
  • the biodegradable polymeric materials, as well as the agents (such as cell factors) in the core and/or the shell provides a specific microenvironment (including, for example, growth factors and nutrients for cell growth and differentiation, space for cell proliferation and differentiation, physical factor and mechanical stimulus for promoting biological functions of the cell, feeder cells for cooperating or regulating stem cell differentiation, etc. ) to regulate activities and function of the cell;
  • the core-shell structure of the bio-block allows the bio-block to have suitable hardness, mechanical strength, and elastic modulus to provide mechanical protection and stable physical space for cell survival and growth in the bio-blocks;
  • the bio-block enables precise cell distribution in multi-dimensional structures constructed thereof (such as by bioprinting) .
  • different types of bio-blocks which may have different structures, different types of cells, different types of cell factors, and/or different biodegradable polymeric material, can be prepared according to the need.
  • the different types of bio-blocks can then be used in bioprinting, and optionally be cultured to proliferate without disrupting the pre-determined cell distribution pattern, in order to obtain an artificial tissue with precise cell distribution patterns;
  • the cell can be regulated using one or more cell factors or pharmaceutically active agents that are supplemented in the bio-block to promote proliferation, differentiation, migration, metabolism, and/or secretion;
  • the shell is degradable, such as by including oxidized alginate in the biodegradable polymeric shell material, and the degradation rate of the shell can be controlled (such as by choosing a suitable oxidation level of the oxidized alginate) to match the growth rate of cells in the bio-block.
  • a bio-block comprising: a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) , and b) a shell comprising a biodegradable polymeric shell material.
  • a bio-ink composition comprising a plurality of bio-blocks each comprising: a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) , and b) a shell comprising a biodegradable polymeric shell material.
  • the bio-ink composition further comprises a carrier.
  • a method of preparing an artificial tissue or a tissue progenitor comprising bioprinting a bio-ink composition to obtain a multi-dimensional construct having a pre-determined pattern, wherein the bio-ink composition comprises a plurality of bio-blocks each comprising: a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) , and b) a shell comprising a biodegradable polymeric shell material.
  • a cell refers to a type of cell, including any number (such as one or more) of cells of the same type. Cells may be classified into different types based on their sources, tissues of origin, morphologies, functions, histological markers, expression profiles, or the like. “Seed cell” refers to the cell that is included in the core of the bio-block during the preparation step of the bio-block. “Cell” includes the seed cell and any of its progeny.
  • endothelial cell refers to “vascular endothelial cell” or “cell wall endothelial cell” , which is a type of cell that lines the interior surface of blood vessels or capillaries.
  • stem cell includes pluripotent or totipotent undifferentiated cell, as well as progenitor cells that are multipotent or unipotent, and can differentiate into a specialized cell.
  • blood capillary and “microvessels” are used interchangeably to refer to a blood vessel that connects arterioles and venules, which are small blood vessels in animals with an average diameter of about 5 ⁇ m to about 10 ⁇ m.
  • Blood capillaries are widely distributed in all tissues of an animal, except for cartilage, cornea, hair, and enamel. Blood capillaries have thin walls (such as one cell layer thick) , highly permeability, and highly branched structures within extended networks, which facilitate exchange of substances between blood and tissues.
  • “Microvasculature” or “microvascular network” refers to the network of blood capillaries.
  • tissue-specific cell refers to a differentiated cell that is typically found in a tissue.
  • hepatocytes are liver-specific cells.
  • bio-block refers to a cell-based basic building block that can be used in many fields, such as bioprinting (e.g., 3D bioprinting) , tissue engineering, and regenerative medicine.
  • the bio-block of the present application comprises a one or more cores each comprising one or more cells, and one or more shells each coats at least one core, wherein the one or more cores and the one or more shells each (for example, independently) comprise a biodegradable material.
  • FIG. 1B-1F Schematic diagrams showing exemplary core-shell structures of bio-blocks are depicted in FIG. 1B-1F.
  • MSC bio-block refers to a bio-block comprising at least one core comprising one or more mesenchymal stem cells (MSC) .
  • bio-ink refers to a liquid or paste composition suitable for bioprinting, wherein the composition comprises one or more types of bio-blocks.
  • the bio-ink can be a solution, suspension, gel, or concentrate containing bio-blocks.
  • the bio-ink comprises a plurality of bio-blocks and a carrier, such as a cell-adhesive carrier.
  • the bio-ink can be used for bioprinting to obtain a planar and/or sheet-like structure having pre-determined dimensions.
  • the planar and/or sheet-like structure can be further deposited to form a three-dimensional construct having a pre-determined shape and structure.
  • Cells in the bio-blocks of the bio-ink composition can engage in expected life activities before, during, and/or after bioprinting.
  • bioprint refers to printing using a material comprising biological substances, including biological molecules derived from biological sources (e.g. proteins, lipids, carbohydrates, nucleic acids, metabolites, and/or small molecules) , cells, subcellular structures (e.g. organelles, membranes, etc. ) , groups of cells, groups of subcellular structures, or molecules that are related to biological molecules (e.g. synthetic biological molecules or synthetic analogs of biological molecules) .
  • Print refers to a process of depositing a material according to a pre-determined pattern, design or scheme.
  • Print (such as bioprinting) described herein can be carried out by a variety of methods, including, but not limited to, printing using a printer (such as a 3D printer or bioprinter) , printing using an automated or non-automated mechanical process rather than a printer, and printing by manual deposition (e.g. using a pipette) .
  • a printer such as a 3D printer or bioprinter
  • printing using an automated or non-automated mechanical process rather than a printer e.g. using a pipette
  • tissue refers to an ensemble of one or more groups of cells each having the same or similar morphology and functions. Tissue typically further comprises non-cell materials known as intercellular substance, such as extracellular matrix and fibers.
  • a tissue may include a single type of cells or multiple types of cells.
  • organ refers to a structural unit comprising one or more tissues for serving one or more specific bodily functions. In some embodiments, an organ consists of a single tissue. In some embodiments, an organ comprises multiple tissues.
  • Artificial tissue refers to a tissue that is not formed through natural tissue generation or development processes inside a biological organism. In some embodiments, an artificial tissue is a man-made tissue, such as a bioprinted tissue.
  • tissue progenitor refers to an ensemble of cells that are capable of forming a tissue that can carry out a specific function, upon culturing, induction, or other manipulation steps.
  • a tissue progenitor is a man-made (i.e. “artificial” ) tissue progenitor.
  • the cells in the tissue progenitor are not connected to each other. In some embodiments, the cells in the tissue progenitor are partially connected to each other.
  • multi-dimensional construct refers to a structure of at least one dimension, and typically no more than three dimensions. In some embodiments, the multi-dimensional construct is a two-dimensional structure. In some embodiments, the multi-dimensional construct is a three-dimensional structure.
  • biodegradable material refers to material that can be degraded and/or absorbed by cells or organisms, and the degradation materials are biocompatible.
  • Biodegradable material can be obtained from a natural source (such as from animals or plants) , modified from a naturally-occurring material, or synthesized.
  • Biocompatible material refers to non-cytotoxic material (including degradation products thereof) .
  • Biocompatible material can be transplanted into a host (such as human) without causing significant or severe adverse effects. For example, the biocompatible material does not cause cytotoxic effects to the host (such as human tissue) , or induce immune rejection, allergy, or inflammation in the host.
  • mechanical protection refers to reduction or avoidance of external mechanical or physical damage (such as damage due to shearing force or pressure generated in a 3D bioprinting process) to cells, for example, as provided by shells having a suitable hardness and elastic modulus in bio-blocks.
  • agent refers to a chemical, molecule, biochemical, or drug, including, but not limited to a small molecule compound, a hormone, a peptide (such as an oligopeptide, or a protein) , a nucleic acid (such as an oligonucleotide, a DNA, an RNA, or a chemically modified nucleic acid) , or the like, which can have an effect on cellular activities, functions, and/or behaviors.
  • the agent may be derived from a natural source, produced using recombinant methods, or synthesized chemically.
  • the agents can have the same molecular identity as factors or molecules secreted or produced by cells in the bio-blocks, but the agents described herein are obtained from exogenous sources other than the cells in the bio-blocks.
  • cell factor refers to an agent that mediates signaling inside or among cells.
  • a cell factor may maintain, promote, improve or regulate proliferation, differentiation, migration, metabolism, and/or secretion of a cell.
  • stirred refers to a chemical factor (such as agent, acid, base, oxygen concentration, etc. ) or a physical factor (such as temperature, light, mechanical force, etc. ) , which can have an effect on cellular activities, functions, and/or behaviors.
  • a chemical factor such as agent, acid, base, oxygen concentration, etc.
  • a physical factor such as temperature, light, mechanical force, etc.
  • a “subject” refers to an animal, such as vertebrates.
  • the subject is a mammal, including, but not limited to, human, bovine, horse, feline, canine, rodent, or primate.
  • the subject is a human.
  • “Patient” , “subject” , and “individual” are used herein interchangeably.
  • length of a three-dimensional object is defined as the longest line within the body of the object.
  • Width of the three-dimensional object is defined as the longest line in the body of the object that is orthogonal to the length.
  • Thinickness of the three-dimensional object is defined as the longest line in the body of the object that is orthogonal to both length and width, wherein the thickness is shorter or equal to the width.
  • the length, width, and thickness of the object equal to the diameter.
  • the direction of the length of the object is defined as the “x-axis, ” the direction of the width of the object is defined as the “y-axis, ” and the direction of the thickness of the object is defined as the “z-axis. ”
  • percentage refers to weight by weight (i.e., w/w) percentage.
  • ratio refers to weight by weight (i.e., w/w) ratio.
  • references to "about” a value or parameter herein includes (and describes) variations that are directed to that value or parameter per se. For example, description referring to "about X” includes description of "X” .
  • reference to "not" a value or parameter generally means and describes "other than” a value or parameter.
  • the method is not used to treat cancer of type X means the method is used to treat cancer of types other than X.
  • the present invention provides bio-blocks comprising endothelial cells and optionally stem cells useful for making multi-dimensional constructs of a pre-determined pattern, tissue progenitors, and ultimately artificial tissues.
  • a bio-block comprising: (a) a core comprising a biodegradable core material (such as a polymeric material) , and an endothelial cell; and (b) a shell comprising a biodegradable shell material (such as a polymeric material) .
  • a bio-block comprising: (a) a core comprising a biodegradable core material (such as a polymeric material) , an endothelial cell and a stem cell (such as a mesenchymal stem cell) ; and (b) a shell comprising a biodegradable shell material (such as a polymeric material) .
  • a bio-block comprising: (a) a core comprising a biodegradable core material (such as a polymeric material) , and an endothelial cell; and (b) a second core comprising a second biodegradable core material (such as polymeric material) , and a stem cell (such as MSC) ; and (c) a shell comprising a biodegradable shell material (such as a polymeric material) .
  • a bio-block comprising: (a) a core comprising a biodegradable core material (such as a polymeric material) , an endothelial cell, a stem cell (such as a mesenchymal stem cell) , and a hepatocyte; and (b) a shell comprising a biodegradable shell material (such as a polymeric material) .
  • a bio-block comprising: (a) a core comprising a biodegradable core material (such as a polymeric material) , an endothelial cell, a stem cell (such as a mesenchymal stem cell) , and a smooth muscle cell; and (b) a shell comprising a biodegradable shell material (such as a polymeric material) .
  • any one of the bio-blocks described above may have one or more (such as any of 1, 2, 3, 4, 5, or 6) of the following properties or characteristics: (1) the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) ; (2) the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) ; (3) the biodegradable polymeric core material comprises type I collagen; (4) the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) ; (5) the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa; and (6) the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores. In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) .
  • the length of the bio-block is about 30 ⁇ m to about 2 mm.
  • the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) .
  • the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) .
  • the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa.
  • the shell comprises one or more micropores.
  • the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa.
  • the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) .
  • the length of the bio-block is about 30 ⁇ m to about 2 mm.
  • the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) .
  • the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores. In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) .
  • the length of the bio-block is about 30 ⁇ m to about 2 mm.
  • the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) .
  • the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores. In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm.
  • the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) .
  • the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutically active agent.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm.
  • the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) .
  • the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) .
  • the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa.
  • the shell comprises one or more micropores (such as with a size of more than about 50 nm) .
  • the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa.
  • the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the biodegradable polymeric core material comprises type I collagen.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm.
  • the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) .
  • the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , and wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) .
  • the length of the bio-block is about 30 ⁇ m to about 2 mm.
  • the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) .
  • the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) .
  • the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa.
  • the shell comprises one or more micropores (such as with a size of more than about 50 nm) .
  • the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa.
  • the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , and wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) .
  • the length of the bio-block is about 30 ⁇ m to about 2 mm.
  • the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) .
  • the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) .
  • the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa.
  • the shell comprises one or more micropores (such as with a size of more than about 50 nm) .
  • the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa.
  • the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , and wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm.
  • the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) .
  • the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) .
  • the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa.
  • the shell comprises one or more micropores (such as with a size of more than about 50 nm) .
  • the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa.
  • the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , and wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutically active agent.
  • an agent such as at least 3 different agents
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , and wherein the biodegradable polymeric core material comprises type I collagen.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm.
  • the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) .
  • the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) .
  • the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa.
  • the shell comprises one or more micropores (such as with a size of more than about 50 nm) .
  • the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa.
  • the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , and wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) .
  • the length of the bio-block is about 30 ⁇ m to about 2 mm.
  • the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) .
  • the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) .
  • the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa.
  • the shell comprises one or more micropores (such as with a size of more than about 50 nm) .
  • the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa.
  • the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , and wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm.
  • the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) .
  • the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) .
  • the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa.
  • the shell comprises one or more micropores (such as with a size of more than about 50 nm) .
  • the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa.
  • the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , and wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutically active agent.
  • a tissue-specific cell such as a hepatocyte, or a smooth muscle cell
  • the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secret
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , and wherein the biodegradable polymeric core material comprises type I collagen.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm.
  • the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) .
  • the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) .
  • the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa.
  • the shell comprises one or more micropores (such as with a size of more than about 50 nm) .
  • the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa.
  • the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , and wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm.
  • the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) .
  • the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) .
  • the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa.
  • the shell comprises one or more micropores (such as with a size of more than about 50 nm) .
  • the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa.
  • the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , and wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutically active agent.
  • an agent such as at least 3 different agents
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , and wherein the biodegradable polymeric core material comprises type I collagen.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm.
  • the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) .
  • the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) .
  • the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa.
  • the shell comprises one or more micropores (such as with a size of more than about 50 nm) .
  • the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa.
  • the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa, and wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutically active agent.
  • an agent such as at least 3 different agents
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa, and wherein the biodegradable polymeric core material comprises type I collagen.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm.
  • the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) .
  • the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) .
  • the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa.
  • the shell comprises one or more micropores (such as with a size of more than about 50 nm) .
  • the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa.
  • the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutically active agent, and wherein the biodegradable polymeric core material comprises type I collagen.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm.
  • the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) .
  • the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) .
  • the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa.
  • the shell comprises one or more micropores (such as with a size of more than about 50 nm) .
  • the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa.
  • the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , and wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) .
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , and wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , and wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutically active agent.
  • an agent such as at least 3 different agents
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , and wherein the biodegradable polymeric core material comprises type I collagen.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , and wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , and wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutically active agent.
  • an agent such as at least 3 different agents
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , and wherein the biodegradable polymeric core material comprises type I collagen.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa, and wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutically active agent.
  • an agent such as at least 3 different agents
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa, and wherein the biodegradable polymeric core material comprises type I collagen.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutically active agent, and wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , and wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm.
  • the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) .
  • the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) .
  • the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa.
  • the shell comprises one or more micropores (such as with a size of more than about 50 nm) .
  • the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa.
  • the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , and wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutically active agent.
  • an agent such as at least 3 different agents
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , and wherein the biodegradable polymeric core material comprises type I collagen.
  • the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) .
  • the length of the bio-block is about 30 ⁇ m to about 2 mm.
  • the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) .
  • the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) .
  • the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa, and wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutically active agent.
  • an agent such as at least 3 different agents
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa, and wherein the biodegradable polymeric core material comprises type I collagen.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm.
  • the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) .
  • the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) .
  • the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa.
  • the shell comprises one or more micropores (such as with a size of more than about 50 nm) .
  • the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa.
  • the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutically active agent, and wherein the biodegradable polymeric core material comprises type I collagen.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa, and wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutically active agent.
  • an agent such as at least 3 different agents
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa, and wherein the biodegradable polymeric core material comprises type I collagen.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm.
  • the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) .
  • the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) .
  • the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa.
  • the shell comprises one or more micropores (such as with a size of more than about 50 nm) .
  • the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa.
  • the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutically active agent, and wherein the biodegradable polymeric core material comprises type I collagen.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa, wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutically active agent, and wherein the biodegradable polymeric core material comprises type I collagen.
  • the biodegradable polymeric core material comprises type I collagen.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa, wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutically active agent, and wherein the biodegradable polymeric core material comprises type I collagen.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutically active agent, and wherein the biodegradable polymeric core material comprises type I collagen.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa, and wherein the biodegradable polymeric core material comprises type I collagen.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa, and wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutically active agent.
  • an agent such as at least 3 different agents
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa, wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutically active agent, and wherein the biodegradable polymeric core material comprises type I collagen.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising : (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutically active agent, and wherein the biodegradable polymeric core material comprises type I collagen.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa, and wherein the biodegradable polymeric core material comprises type I collagen.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa, and wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutically active agent.
  • an agent such as at least 3 different agents
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutically active agent, and wherein the biodegradable polymeric core material comprises type I collagen.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa, and wherein the biodegradable polymeric core material comprises type I collagen.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa, and wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) ,
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , and wherein the biodegradable polymeric core material comprises type I collagen.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , and wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , and wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa, and wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa, and wherein the biodegradable polymeric core material comprises type I collagen.
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutical
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa, wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa, wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutically active agent, and wherein the biode
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa, wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutically active agent, and wherein the biodegradable polymeric core material comprises type I collagen.
  • the bio-block such
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa, wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-block comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and (b) a shell comprising a biodegradable polymeric shell material; wherein the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) , wherein the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) , wherein the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) , wherein the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa, wherein the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor
  • bio-block can be customized to satisfy the different needs in constructing artificial tissues with different multi-dimensional constructs and cell distribution patterns. It is intended that any of the properties (such as composition, ratio, physical and chemical properties, etc. ) of one component (such as cell, biodegradable material, agent, core, shell, etc. ) of the bio-block as described herein can be combined with any of the properties of another component of the bio-block as described herein, as if each and every combination is individually described. Descriptions of the properties and components below apply to each core and shell, or subcomponents (such as cell) thereof, of the bio-block.
  • the bio-blocks of the present application comprise one or more endothelial cells.
  • the bio-block comprises one or more endothelial cells and one or more stem cells (such as MSC) in the same core in different cores.
  • the bio-block comprise one or more endothelial cells, one or more stem cells (such as MSC) , and one or more tissue-specific cells (such as hepatocyte or smooth muscle cell) in the same core, or in different cores.
  • the core comprises the endothelial cell only.
  • the bio-block comprises a core comprising the stem cell (such as MSC) only.
  • the bio-block comprises a core comprising the tissue-specific cell (such as hepatocyte or smooth muscle cell) only.
  • the core comprises both the endothelial cell and the stem cell.
  • the core comprises both the endothelial cell and the tissue-specific cell.
  • the bio-block comprises a core comprising both the stem cell and the tissue-specific cell.
  • the core comprises the endothelial cell, the stem cell, and the tissue-specific cell.
  • the core comprises about any of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, or more types of endothelial cells. In some embodiments, the core comprises about any of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, or more types of stem cells (such as MSC) . In some embodiments, the core comprises about any of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, or more types of tissue-specific cells.
  • the endothelial cell is derived from an artery or an arteriole. In some embodiments, the endothelial cell is derived from a vein or venules. In some embodiments, the endothelial cell is an endothelial cell from a mammal. In some embodiments, the endothelial cell is a human endothelial cell, such as HUVEC. In some embodiments, the endothelial cell is a rat endothelial cell.
  • the core may comprise any number of the endothelial cell, including, for example, at least about any of 1, 2, 4, 6, 8, 10, 15, 20, 25, 30, 40, 50, 60, 70, 80, 90, 100, 150, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000, 5000, 10000, 20000, 30000, 40000, 50000, 100000, 200000, 500000, or 1000000 endothelial cells.
  • the core comprises about any of 1-10, 10-900, 20-800, 30-700, 40-600, 50-500, 60-400, 70-300, 80-200, 10-100, 10-1000, 10-10000, 10-100000, or 1-1000000 endothelial cells.
  • the endothelial cell may be present at a suitable percentage of the total number of cells in the core.
  • the number of the endothelial cell is about 1%-100%, such as about any of 2%-90%, 3%-80%, 4%-70%, 5%-60%, 5.5%-50%, 6%-40%, 6.5%-30%, 7%-20%, 7.5%-19%, 8%-18%, 8.5%-17%, 9%-16%, 9.1%-15%, 9.2%-14%, 9.3%-13%, 9.4%-12%, 9.5%-11.5%, 9.6%-11%, 9.7%-10.9%, 9.8%-10.8%, 9.9%-10.7%, 9.9%-10.6%, 9.9%-10.5%, 9.9%-10.4%, 9.9%-10.3%, 9.9%-10.2%, 9.9%-10.1%, 1%-5%, 5%-6%, 6%-7%, 7%-8%, 8%-9%, 9%-10%, 10%-11%, 11%-12%, 12%-13%, 13%-14%, 14%-15%, 5%-8%,
  • the stem cell is unipotent. In some embodiments, the stem cell is a progenitor cell. In some embodiments, the stem cell is pluripotent. In some embodiments, the stem cell is totipotent. In some embodiments, the stem cell is an induced pluripotent stem cell (iPS) . In some embodiments, the stem cell is an embryonic stem cell. In some embodiments, the stem cell is an adult stem cell. In some embodiments, the core comprises more than one (such as any of 2, 3, 4, 5, 6, or more) type of stem cells. In some embodiments, the stem cell is a hematopoietic stem cell. In some embodiments, the stem cell is a mesenchymal stem cell (MSC) .
  • MSC mesenchymal stem cell
  • the stem cell is derived from the bone marrow. In some embodiments, the stem cell is derived from a non-marrow source, such as the umbilical cord, placental tissue, peripheral blood, adipose tissue, teeth, or skin.
  • a non-marrow source such as the umbilical cord, placental tissue, peripheral blood, adipose tissue, teeth, or skin.
  • the MSC is a bone marrow stromal cell or a bone marrow-derived mesenchymal stem cell (BMSC) .
  • the MSC is derived from the umbilical cord tissue, such as Wharton’s jelly or the umbilical cord blood.
  • the MSC is derived from the amniotic fluid.
  • the MSC is derived from an adipose tissue.
  • the MSC is derived from a dental pulp tissue.
  • the MSC is derived from skin or hair follicles.
  • the MSC is derived from adult muscle.
  • the MSC is derived from corneal stroma.
  • the MSC is derived from the synovial membrane. In some embodiments, the MSC is derived from joint-related tissues, such as meniscus, intra-articular ligament, and infrapatellar fat pad.
  • the MSC of suitable origins can be chosen for bio-blocks to tailor to the specific composition of a given artificial tissue. For example, a bio-block comprising an adipose-derived MSC may be suitable for preparing a liver tissue.
  • the core may comprise any number of the stem cell (such as MSC) , including, for example, at least about any of 1, 2, 4, 6, 8, 10, 15, 20, 25, 30, 40, 50, 60, 70, 80, 90, 100, 150, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000, 5000, 10000, 20000, 30000, 40000, 50000, 100000, 200000, 500000, or 1000000 stem cells (such as MSC) .
  • the stem cell such as MSC
  • MSC the stem cell
  • the core comprises about any of 1-10, 10-900, 20-800, 30-700, 40-600, 50-500, 60-400, 70-300, 80-200, 10-100, 10-1000, 10-10000, 10-100000, or 1-1000000 stem cells (such as MSC) .
  • the stem cell (such as MSC) may be present at a suitable percentage of the total number of cells in the core.
  • the number of the stem cell (such as MSC) is at least about any of 10%, 20%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 85%, 90%, 95%, or more of the total number of cells in the core.
  • the number of the stem cell (such as MSC) is about any one of 0%-99%, 1%-99%, 5%-80%, 10%-70%, 15%-65%, 20%-60%, 25%-55%, 30%-50%, 35%-45%, 36%-44%, 37%-43%, 38%-42%, 39%-41%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-75%, 75%-80%, 80%-90%, 90%- 95%, 95%-98%, 10%-40%, 40%-80%, 50%-95%, 70%-95%, 80%-95%, 70%-95%, or 10%-95%of the total number of cells in the core.
  • the tissue-specific cell is derived from an epithelial, muscular, nervous, or connective tissue, or any combination thereof.
  • the tissue-specific cell is derived from a tissue selected from the group consisting of liver, gastrointestinal, pancreatic, kidney, lung, tracheal, vascular, skeletal muscle, cardiac, skin, smooth muscle, connective tissue, corneal, genitourinary, breast, reproductive, endothelial, epithelial, fibroblast, neural, Schwann, adipose, bone, bone marrow, pericytes, mesothelial, endocrine, stromal, lymph, and blood.
  • the tissue-specific cell is derived from a tumor.
  • the tissue-specific cell is selected from the group consisting of liver cell (i.e., hepatocyte) , gastrointestinal cell, pancreatic cell, kidney cell, lung cell, tracheal cell, vascular cell, skeletal muscle cell, cardiac cell, skin cell, smooth muscle cell, connective tissue cell, corneal cell, genitourinary cell, breast cell, reproductive cell, endothelial cell, epithelial cell, fibroblast, neural cell, Schwann cell, adipose cell, bone cell, bone marrow cell, pericyte, mesothelial cell, cell derived from endocrine tissue, and stromal cell.
  • liver cell i.e., hepatocyte
  • pancreatic cell kidney cell
  • lung cell tracheal cell
  • vascular cell vascular cell
  • skeletal muscle cell cardiac cell
  • skin cell smooth muscle cell
  • connective tissue cell corneal cell
  • endothelial cell epithelial cell
  • fibroblast neural cell
  • Schwann cell ad
  • Tissue-specific cells of appropriate type can be chosen for bio-blocks to tailor to the specific composition of a given artificial tissue.
  • the tissue-specific cell is a cardiomyocyte, wherein the bio-block is useful for preparing a cardiac tissue.
  • the tissue-specific cell is a smooth muscle cell, wherein the bio-block is useful for preparing a muscle tissue.
  • the tissue specific cell is a hepatocyte, wherein the bio-block is useful for preparing a liver tissue.
  • the core may comprise any number of the tissue-specific cell (such as hepatocyte or smooth muscle cell) , including, for example, at least about any of 1, 2, 4, 6, 8, 10, 15, 20, 25, 30, 40, 50, 60, 70, 80, 90, 100, 150, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000, 5000, 10000, 20000, 30000, 40000, 50000, 100000, 200000, 500000, or 1000000 tissue-specific cells (such as hepatocyte or smooth muscle cell) .
  • tissue-specific cell such as hepatocyte or smooth muscle cell
  • the core comprises about any of 1-10, 10-900, 20-800, 30-700, 40-600, 50-500, 60-400, 70-300, 80-200, 10-100, 10-1000, 10-10000, 10-100000, or 1-1000000 tissue-specific cells (such as hepatocyte or smooth muscle cell) .
  • the tissue-specific cell (such as hepatocyte or smooth muscle cell) may be present at a suitable percentage of the total number of cells in the core.
  • the number of the tissue-specific cell is at least about any of 1%, 5%, 10%, 15%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or more of the total number of cells in the core.
  • the number of the tissue-specific cell is about any one of 1%-5%, 5%-10%, 10%-15%, 15%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 10%-40%, 40%-80%, 50%-90%, 1%-10%, 5%-15%, 1%-20%, or 5%-90%of the total number of cells in the core.
  • the core comprises at least about any of 1, 2, 4, 6, 8, 10, 15, 20, 25, 30, 40, 50, 60, 70, 80, 90, 100, 150, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000, 5000, 10000, 20000, 30000, 40000, 50000, 100000, 200000, 500000, or 1000000 total number of cells.
  • the core comprises no more than about any of 2, 5, 10, 20, 30, 40, 50, 100, 200, 300, 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000, 5000, 10000, 20000, 30000, 40000, 50000, 100000, 200000, 500000, or 1000000 total number of cells.
  • the core comprises a total of about 1 cell to about 1000000 cells. In some embodiments, the core comprises a total of at least 50 cells. In some embodiments, the core comprises a total of about 1 cell to about 5000 cells, including, for example, about 2 cells to about 50 cells, or about 100 cells to about 5000 cells.
  • the ratio between the number of the endothelial cell and the number of the stem cell in the bio-block can be optimized to provide a suitable number of blood capillaries for an artificial tissue, tissue progenitor, or construct prepared using the bio-block.
  • the ratio between the number of the endothelial cell and the number of the stem cell is at least about any of 1: 20, 1: 19, 1: 18, 1: 17, 1: 16, 1: 15, 1: 14, 1: 13, 1: 12, 1: 11, 1: 10.5, 1: 10, 1: 9.5, 1: 9, 1: 8.5, 1: 8, 1: 7, 1: 6, 1: 5, 1: 4, 1: 3, 1: 2, 2: 3, or 1: 1.
  • the ratio between the number of the endothelial cell and the number of the stem cell is about 1: 20 to about 1: 1, such as about any one of 1: 20 to 1: 15, 1: 15 to 1: 10, 1: 10 to 1: 5, 1: 5 to 1: 1, 1: 20 to 1: 18, 1: 18 to 1: 16, 1: 16 to 1: 14, 1: 14 to 1: 12, 1: 12 to 1: 10, 1: 10 to 1: 8, 1: 8 to 1: 6, 1: 6 to 1: 4, 1: 4 to 1: 2, 1: 10.5 to 1: 9.5, 1: 11 to 1: 9, 1: 12 to 1: 8, 1: 13 to 1: 7, 1: 14 to 1: 6, 1: 15 to 1: 5, or 1: 20 to 2: 3.
  • the ratio between the number of the endothelial cell and the number of the stem cell is about 1: 10.
  • the bio-block comprising HUVEC and bone marrow derived MSC at a ratio of about 1: 10 can be used to prepare an artificial tissue or construct having a large number of blood capillaries.
  • the ratio between the number of the endothelial cell and the number of the tissue-specific cell in the bio-block can be optimized to provide a sufficiently vascularized artificial tissue, tissue progenitor, or construct prepared using the bio-block.
  • the ratio between the number of the tissue-specific cell to the number of the endothelial cell is at least about any of 1: 20, 1: 10, 1: 5, 1: 2, 1: 1, 2: 1, 3: 1, 4: 1, 5: 1, 10: 1, 20: 1 or more.
  • the ratio between the number of the tissue-specific cell to the number of the endothelial cell is about any one of 1: 20 to 1: 1, 1: 10 to 1: 5, 1: 5 to 1: 2, 1: 2 to 1: 1, 1: 1 to 2: 1, 2: 1 to 3: 1, 3: 1 to 4: 1, 4: 1 to 5: 1, 5: 1 to 10: 1, 10: 1 to 20: 1, 1: 5 to 1: 1, 1: 1 to 5: 1, 1: 1 to 10: 1, 1: 10 to 1: 1, 1: 5 to 5: 1, 1: 10 to 10: 1, or 1: 20 to 20: 1.
  • the bio-block comprising HUVEC and hepatocyte at a ratio of about 1: 1 can be used to prepare an artificial tissue (such as liver tissue) with blood capillaries.
  • the bio-block comprising HUVEC, bone marrow-derived HUVEC and hepatocyte at a ratio of about 1: 1: 10 can be used to prepare an artificial tissue (such as liver tissue) with blood capillaries.
  • the endothelial cell, the stem cell (such as MSC) , and/or tissue-specific cell is an animal cell.
  • the endothelial cell, the stem cell (such as MSC) , and/or tissue-specific cell is derived from a mammal, such as from human, ape, gorilla, cow, pig, dog, sheep, goat, rat and mice.
  • the endothelial cell, the stem cell (such as MSC) , and/or tissue-specific cell is a human cell.
  • the endothelial cell, the stem cell (such as MSC) , and/or tissue-specific cell is a rat cell.
  • the endothelial cell, the stem cell (such as MSC) , and optionally the tissue-specific cell are derived from the same organism, such as human, or rat.
  • the endothelial cell, the stem cell (such as MSC) , and/or tissue-specific cell is isolated from natural sources, such as a tissue biopsy. In some embodiments, the endothelial cell, the stem cell (such as MSC) , and/or tissue-specific cell is isolated from an in vitro cultured cell line. In some embodiments, the endothelial cell, the stem cell (such as MSC) , and/or tissue-specific cell is a genetically engineered cell. In some embodiments, the endothelial cell, the stem cell (such as MSC) , and/or tissue-specific cell is a seed cell that undergoes proliferation, differentiation, or both in the core.
  • the endothelial cell, the stem cell (such as MSC) , and/or tissue-specific cell is derived from a primary cell. In some embodiments, the endothelial cell, the stem cell (such as MSC) , and/or tissue-specific cell is derived from a cell line.
  • a bio-block comprising a core comprising a biodegradable polymeric core material, an endothelial cell and a stem cell (such as MSC) , and a shell comprising a biodegradable polymeric shell material.
  • the core comprises the endothelial cell and the stem cell (such as MSC) embedded in the biodegradable polymeric core material.
  • the core comprises the endothelial cell and the stem cell (such as MSC) enwrapped by the biodegradable polymeric core material.
  • the endothelial cell and the stem cell are evenly distributed within the core.
  • the endothelial cell and the stem cell are aggregated in the center or another location inside the core.
  • the endothelial cell and the stem cell are immobilized in the core.
  • the endothelial cell and the stem cell can diffuse freely in the core.
  • the shell provides mechanical support to the core.
  • FIG. 1A shows a schematic cartoon of an exemplary embodiment of a bio-block, wherein the shell of the bio-block is the exterior layer of the bio-block that surrounds and mechanically protects the core in the interior, which comprises the endothelial cell and the stem cell (such as MSC) .
  • a bio-block comprising a core and a shell, wherein the core comprises a cell, and wherein the shell coats the core.
  • “Coat” or “coating” refers to the structural relationship of two adjacent structural layers, wherein the outer structural layer covers, surrounds, enwraps, or embeds (i.e. coats) the inner structural layer.
  • the shell does not comprise a cell.
  • the core comprises a biodegradable core material.
  • the shell comprises a biodegradable shell material.
  • the biodegradable core material and the biodegradable shell material are identical.
  • the biodegradable core material and the biodegradable shell material are different.
  • the bio-block may have a combination of any number of cores (such as any one of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) and any number of shells (such as any one of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) .
  • the bio-block of the present invention may adopt a variety of structures, including, but not limited to the structures illustrated in FIGs. 1B-1F.
  • the most interior structural layer of the bio-block is a core
  • the most exterior structural layer of the bio-block is a shell.
  • Each core may be coated (such as surrounded, enwrapped, or embedded) by a shell, or a second core.
  • a shell may be coated (such as surrounded, enwrapped, or embedded) by a second shell or a core, or a shell may be the most exterior structural layer of the bio-block.
  • the bio-block may contain consecutive structural layers being all cores, or being all shells.
  • the bio-block may also contain alternating structural layers, wherein core and shell alternates in at least three consecutive structural layers, e.g., in the order of core-shell-core or shell-core-shell.
  • the bio-block may also comprise a combination of consecutive structural layers and alternating structural layers.
  • a shell coats two or more cores.
  • the bio-block consists of (including consists essentially of) a single core and a single shell. In some embodiments, the bio-block consists (including consists essentially of) of a single shell coating a single core. In some embodiments, the bio-block has a structure as shown in FIG. 1B.
  • the bio-block comprises at least two (such as at least about any of 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) cores. In some embodiments, the bio-block comprises at least two (such as at least about any of 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) shells. In some embodiments, the bio-block comprises a single core and at least two (such as at least about any of 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) shells, wherein the single core is the most interior structural layer of the bio-block. In some embodiments, the at least two shells are consecutive with respect to each other.
  • the bio-block comprises a first shell, a second shell and a single core, wherein the first shell coats the single core, and the second shell coats the first shell.
  • the bio-block has a structure as shown in FIG. 1C.
  • the bio-block comprises at least two (such as at least about any of 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) cores and a single shell, wherein the single shell is the most exterior structural layer of the bio-block.
  • the at least two cores are consecutive with respect to each other.
  • the bio-block comprises a first core, a second core and a single shell, wherein the second core coats the first core, and the single shell coats the second core.
  • the bio-block has a structure as shown in FIG. 1D.
  • the bio-block comprises at least two (such as at least about any of 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) cores and at least two (such as at least about any of 2, 3, 4, 5, 6, 7, 8, 9, 10, or more) shells.
  • the at least two cores are on the interior side of the bio-block with respect to the at least two shells.
  • the at least two cores are consecutive with respect to each other, and the at least two shells are consecutive with respect to each other.
  • the bio-block comprises a first core, a second core, a first shell, and a second shell, wherein the second core coats the first core, the first shell coats the second core, and the second shell coats the first shell.
  • the bio-block has a structure as shown in FIG. 1E.
  • the bio-block has an alternating core-shell structure.
  • the bio-block comprises a first core, a second core, a first shell, and a second shell, wherein the first shell coats the first core, the second core coats the first shell, and the second shell coats the second core.
  • the bio-block has a structure as shown in FIG. 1F.
  • each core independently enwraps or embeds the endothelial cell and/or the stem cell (such as MSC) .
  • both cores may enwrap or embeds the same type of endothelial cell and the same type of stem cell (such as MSC) at the same ratio between the number of the endothelial cell and the number of the stem cell, or each core may comprise the same type of endothelial cell and the same type of stem cell (such as MSC) at a different ratio between the number of the endothelial cell and the number of the stem cell, or each core may comprise a different type endothelial cell and/or a different type of stem cell (such as MSC) .
  • the bio-block comprises a first core comprising the endothelial cell, and a second core comprising the stem cell (such as MSC) .
  • the bio-blocks can be of any suitable shape.
  • the bio-block is spherical, cubical, rectangular prism, hexagonal prism, cylindrical, or of irregular shape.
  • the bio-block is spherical. Different shapes can be chosen to tailor to the specific need for a given tissue. For example, some shapes (such as spherical, cubical, or hexagonal prism) may allow tight packing of the bio-blocks in a tissue construct. Some shapes (such as irregular shape) may allow construction of special structural features in a tissue or tissue progenitor.
  • the dimensions of the bio-block can be pre-determined according to the desired precision in cell distribution within an artificial tissue.
  • the length of the bio-block is at least about any of 20, 30, 50, 100, 120, 150, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800, 900, 1000, 1500, or 2000 ⁇ m.
  • the length of the bio-block is about any of 20-30, 30-50, 50-100, 100-150, 150-200, 200-250, 250-300, 300-350, 350-400, 400-450, 450-500, 500-600, 600-700, 700-800, 800-900, 900-1000, 1000-1500, 1500-2000, 20-50, 20-100, 100-200, 200-400, 500-600, 600-800, 800-1000, 1000-2000, 20-100, 100-500, 100- 800, 500-1000, 300-800, 30-50, 30-200, 30-500, 30-800, 30-1000, 30-2000, or 20-2000 ⁇ m.
  • the width of the bio-block is at least about any of 20, 30, 50, 100, 120, 150, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800, 900, 1000, 1500, or 2000 ⁇ m. In some embodiments, the width of the bio-block is about any of 20-30, 30-50, 50-100, 100-150, 150-200, 200-250, 250-300, 300-350, 350-400, 400-450, 450-500, 500-600, 600-700, 700-800, 800-900, 900-1000, 1000-1500, 1500-2000, 20-50, 20-100, 100-200, 200-400, 500-600, 600-800, 800-1000, 1000-2000, 20-100, 100-500, 100-800, 500-1000, 300-800, 30-50, 30-200, 30-500, 30-800, 30-1000, 30-2000, or 20-2000 ⁇ m.
  • the thickness of the bio-block is at least about any of 20, 30, 50, 100, 120, 150, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800, 900, 1000, 1500, or 2000 ⁇ m. In some embodiments, the thickness of the bio-block is about any of 20-30, 30-50, 50-100, 100-150, 150-200, 200-250, 250-300, 300-350, 350-400, 400-450, 450-500, 500-600, 600-700, 700-800, 800-900, 900-1000, 1000-1500, 1500-2000, 20-50, 20-100, 100-200, 200-400, 500-600, 600-800, 800-1000, 1000-2000, 20-100, 100-500, 100-800, 500-1000, 300-800, 30-50, 30-200, 30-500, 30-800, 30-1000, 30-2000, or 20-2000 ⁇ m.
  • the ratio between the length and the width of the bio-block is no more than about any of 10: 1, 9: 1, 8: 1, 7: 1, 6: 1, 5: 1, 4: 1, 3: 1, 2: 1, 1.5: 1, or 1: 1.
  • the ratio between the length and the width of the bio-blocks is any of about 1: 1 to about 1.5: 1, about 1: 1 to about 2: 1, about 1: 1 to about 3: 1, about 1: 1 to about 4: 1, about 1: 1 to about 5: 1, about 1: 1 to about 6: 1, about 1: 1 to about 7: 1, about 1: 1 to about 8: 1, about 1: 1 to about 9: 1, or about 1: 1 to about 10: 1.
  • the ratio between the length and the thickness of the bio-block is no more than about any of 100: 1, 90: 1, 80: 1, 70: 1, 60: 1, 50: 1, 40: 1, 30: 1, 20: 1, 10: 1, 9: 1, 8: 1, 7: 1, 6: 1, 5: 1, 4: 1, 3: 1, 2: 1, or 1: 1.
  • the ratio between the length and the thickness of the bio-block is any of about 1: 1 to about 2: 1, about 1: 1 to about 3: 1, about 1: 1 to about 4: 1, about 1: 1 to about 5: 1, about 1: 1 to about 10: 1, about 1: 1 to about 20: 1, about to about 50: 1, or about 1: 1 to about 100: 1.
  • the length of the bio-block is equal to the width of the bio-block. In some embodiments, the width of the bio-block is equal to the thickness of the bio-block. In some embodiments, the bio-block is not a fiber. In some embodiments, the bio-block is not a sheet.
  • the “size” of a spherical bio-block is the diameter of the spherical bio-block.
  • the term “diameter” with its strict geometric definition does not apply to non-spherical bio-blocks.
  • a volume-based particle diameter can be defined as the diameter of the sphere that has the same volume as a given non-spherical bio-block, which can be used to quantitatively define the size of non-spherical bio-blocks.
  • the size of the bio-block i.e.
  • the diameter of the spherical bio-block or the volume-based particle diameter of the non-spherical bio-block is at least about any of 20, 30, 50, 100, 120, 150, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800, 900, 1000, 1500, or 2000 ⁇ m.
  • the size of the bio-block i.e.
  • the diameter of the spherical bio-block or the volume-based particle diameter of the non-spherical bio-block is about any of 20-30, 30-50, 50-100, 100-150, 150-200, 200-250, 250-300, 300-350, 350-400, 400-450, 450-500, 500-600, 600-700, 700-800, 800-900, 900-1000, 1000-1500, 1500-2000, 20-50, 20-100, 100-200, 200-400, 500-600, 600-800, 800-1000, 1000-2000, 20-100, 100-500, 100-800, 500-1000, 300-800, 30-50, 30-200, 30-500, 30-800, 30-1000, 30-2000, or 20-2000 ⁇ m.
  • the size of the bio-block i.e. the diameter of the spherical bio-block or the volume-based particle diameter of the non-spherical bio-block
  • the size of the bio-block is about 20 ⁇ m to about 2 mm, including for example about any of 20-100, 100-500, 500-1000 or 1000-2000 ⁇ m.
  • the size of the bio-block i.e. the diameter of the spherical bio-block or the volume-based particle diameter of the non-spherical bio-block
  • Bio-blocks described herein can be prepared using a variety of methods, including those known in the art for manufacturing microspheriods and microcapsules, such as using an encapsulator as described in Example 1.
  • the shape, dimensions and size of the bio-blocks can be precisely controlled during the preparation process using an encapsulator.
  • the bio-block is prepared under sterile conditions.
  • the bio-block is prepared in a GMP workshop.
  • the bio-block is freshly prepared prior to use.
  • the bio-block can be stored under refrigerated conditions (such as about 4°C) for at least about any of 3 hours, 6 hours, 12 hours, 1 day, 2 days, or 3 days prior to use.
  • the shell consists of a single material layer. In some embodiments, the shell comprises more than one material layers. In some embodiments, the core consists of at least one endothelial cell embedded or enwrapped in a single material layer. In some embodiments, the core comprises more than one material layers. In some embodiments, such as the bio-block illustrated in FIG. 1A, the core comprises a cell-enwrapping or cell-embedding material layer comprising biodegradable polymeric core material. In some embodiments, the core comprises at least one additional material layer placed between the cell-enwrapping or cell-embedding material layer of the core and the shell.
  • the at least one additional material layer of the core enwraps the core, and provides further mechanical support to the core.
  • the shell and the material layer (s) in the core maintain a space with a pre-determined volume and structure for the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) to spread, grow, proliferate, attach (or adhere) , differentiate, metabolize, secrete and/or migrate.
  • the shell and the core of the bio-block may independently comprise a biodegradable material (such as biodegradable polymer) or composition.
  • a biodegradable material such as biodegradable polymer
  • both cores may comprise the same biodegradable material or composition, or each core may comprise a different biodegradable material or composition.
  • the bio-block has three cores
  • all three cores may comprise the same biodegradable material or composition; or each of the three cores may comprise a different biodegradable material or composition; or two of the three cores may comprise the same biodegradable material or composition, and the third core may comprise a different biodegradable material or composition.
  • each core of the bio-block comprises a different composition.
  • the biodegradable core material may be selected independently from the endothelial cell, and/or the stem cell (such as MSC) in the core.
  • different cores of the bio-block may: (1) comprise the same biodegradable material or composition, and the same type of the endothelial cell and the same type of stem cell (such as MSC) at the same ratio between the number of the endothelial cell and the number of the stem cell; (2) comprise the same biodegradable material or composition, and the same type of the endothelial cell and the same type of stem cell (such as MSC) at a different ratio between the number of the endothelial cell and the number of the stem cell; (3) comprise the same biodegradable material or composition, but different types of endothelial cells and/or different types of stem cells (such as MSC) ; (4) comprise different biodegradable material or composition, and different types of endothelial cells and/or different types of stem cells (such as MSC) .
  • the biodegradable polymers for example, the biodegradable polymeric shell material or the biodegradable polymeric core material
  • their degradation products thereof are non-toxic and compatible with the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) in the bio-block.
  • the biodegradable polymers for example, the biodegradable polymeric shell material or the biodegradable polymeric core material
  • their degradation products are non-immunogenic.
  • the biodegradable polymers are degradable by enzymes, such as enzymes secreted from the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) (for example, trypsin) .
  • the biodegradable polymers are degraded completely in no more than about 28 days. In some embodiments, the biodegradable polymers are degraded completely within no more than about any of 21, 14, 12, 10, 9, 8, 7, 6, 5, 4, 3, or 2 days.
  • the biodegradable polymers are degraded completely within no more than about any of 2-5, 2-6, 2-8, 2-10, 2-12, or 2-14 days.
  • the degradation products of the biodegradable polymers provide nutrients for the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) .
  • the rate of degradation of the biodegradable polymeric core and/or shell material is pre-determined using any one or any combination of a variety of methods according to actual application of the bio-block. For example, different biopolymers have different rates of degradation. In some embodiments, to achieve a desirable overall degradation rate of the biodegradable polymeric core and/or shell material, a specific biodegradable polymer of a known degradation rate, or a composition comprising specific biodegradable polymers mixed at a pre-determined weight ratio is used.
  • a low percentage (such as less than about any of 0.5%, 1%, 2%, 5%, 10%, 15%, 20%, or 25%) of a biodegradable polymer with a slow degradation rate (such as with a degradation half-life longer than about any of 1 day, 3 days, 1 week, 2 weeks, 3 weeks, 1 months, 2 months, 3 months, 6 months or a year) is used in the biodegradable polymeric core and/or shell material to achieve a fast overall degradation rate (such as with a half-life of shorter than about any of 1 hour, 5 hours, 10 hours, 1 day, 3 days, 1 week, 2 weeks, 3 weeks, 1 months, 3 months, 6 months, or a year) .
  • a high percentage (such as more than about any of 0.5%, 1%, 2%, 5%, 10%, 15%, 20%, or 25%) of a biodegradable polymer with slow degradation rate (such as with a degradation half-life longer than about any of 1 day, 3 days, 1 week, 2 weeks, 3 weeks, 1 months, 2 months, 3 months, 6 months or a year) is used in the biodegradable polymeric core and/or shell material to achieve a slow overall degradation rate (such as with a half-life of longer than about any of 1 hour, 5 hours, 10 hours, 1 day, 3 days, 1 week, 2 weeks, 3 weeks, 1 months, 3 months, 6 months, or a year) .
  • the degradation rate of a biodegradable polymer typically depends on its (average) molecular weight.
  • a low-molecule weight such as less than about any of 500 Da, 1 kDa, 2 kDa, 3 kDa, 5 kDa, or 10 kDa species of a biodegradable polymer is used in the biodegradable polymeric core and/or shell material.
  • a high-molecule weight (such as more than any of 5 kDa, 10 kDa, 20 kDa, 50 kDa, 100 kDa, 200 kDa, 500 kDa, 1000 kDa or more) species of a biodegradable polymer is used in the biodegradable polymeric core and/or shell material.
  • Additional exemplary methods to control the degradation rate of the biodegradable polymeric core and/or shell material include, but are not limited to, adopting particular parameters for the bio-block (such as number of cell-enwrapping or cell-embedding layers, number, spacing and density of micropores on the shell, surface area of the shell, etc. ) , and manipulations of the preparation process of the biodegradable polymers (such as method of polymerization, ratio of copolymers, crosslinking of polymers, etc. ) .
  • biodegradable materials are known in the art, and their degradation properties have been studied. See, for example, Alexander D. Augst, Hyun Joon Kong, David J. Mooney, “Alginate Hydrogels as biomaterial, ” Macromol. Biosci. 2006, 623-633. Suitable biodegradable materials can be selected to prepare the shell based on actual needs.
  • the biodegradable polymer (for example, the biodegradable polymeric shell material or the biodegradable polymeric core material) is biocompatible and selected from the group consisting of naturally occurring polymer, synthetic polymer, recombinant polymer, and combinations thereof.
  • the biodegradable polymers (for example, the biodegradable polymeric shell material or the biodegradable polymeric core material) comprise naturally occurring polymers, such as biopolymers derived from animals (such as human) and/or plants, or derivatives thereof.
  • Naturally occurring polymers have excellent compatibility profile with cells of all types, are almost always biodegradable on a biologically reasonable timescale, and their degradation products are non-toxic.
  • Derivatives of naturally occurring polymers include modified naturally occurring polymers, which are obtained by modification of a naturally-occurring polymer using chemical and/or physical methods to alter the chemical and/or physical properties of the naturally-occurring polymer.
  • atoms, functional groups or interactions in the main chain or side chains of a naturally-occurring polymer may be modified chemically to obtain a modified naturally-occurring biodegradable polymeric material.
  • sodium alginate may be oxidized to obtain modified sodium alginate, i.e., oxidized sodium alginate.
  • Naturally occurring polymers and derivatives contemplated herein include, but are not limited to, collagen (such as (such as type I collagen, type II collagen or type III collagen) , fibrin, chitosan, alginate, oxidized alginate, starch, hyaluronic acid, laminin, agarose, gelatin, glucan, elastin and combinations thereof.
  • the naturally occurring polymers also include salts of any of the naturally occurring polymers described above, including, but not limited to, sodium salt, potassium salt, calcium salt, strontium salt, and barium salt.
  • the biodegradable polymers (for example, the biodegradable polymeric shell material or the biodegradable polymeric core material) comprise synthetic biodegradable polymers.
  • Synthetic polymers contemplated herein include, but are not limited to, polypohosphazene, polyacrylic acid, polymethacrylic acid, acrylate copolymer (such as copolymer of acrylic acid and polymethacrylic acid) , polylactic acid (PLA) , polyglycolic acid (PGA) , poly- (lactide-coglycolide acid) (PLGA) , polyorthoester (POE) , polycaprolactone (PCL) , polyhydroxyrate (PHB) , polyamino acid (such as polylysine) , degradable polyurethane, copolymers thereof, and combinations thereof.
  • the synthetic polymers also include salts of any of the synthetic polymers described above.
  • the biodegradable polymers (for example, the biodegradable polymeric shell material or the biodegradable polymeric core material) comprise naturally occurring polymers and synthetic polymers.
  • the biodegradable polymeric shell material comprises a naturally occurring polymer and a synthetic polymer.
  • the biodegradable polymeric core material comprises a naturally occurring polymer and a synthetic polymer.
  • the biodegradable polymeric shell material and the biodegradable polymeric core material comprise different biodegradable polymers.
  • the biodegradable polymeric shell material and the biodegradable polymeric core material comprise the same biodegradable polymers with different weight ratios.
  • the biodegradable polymeric core material comprises no more than about 2%(such as no about 1.5%) sodium alginate, and the biodegradable polymeric shell material comprises more than about 4% (such as about 5%) sodium alginate.
  • different material layers within the shell comprise different biodegradable polymers.
  • different material layers within the core comprise different biodegradable polymers.
  • different material layers within the shell comprise the same biodegradable polymers with different weight ratios.
  • different material layers within the core comprise the same biodegradable polymers with different weight ratios.
  • the core, the shell and/or the bio-block may be in a solid or semi-solid state.
  • the bio-block is in a gel state.
  • the core is in a gel state.
  • the bio-block comprises a hydrogel.
  • the hydrogel comprises alginate, oxidized alginate, agarose, gelatin, chitosan, or other water-soluble or hydrophilic polymers.
  • the hydrogel comprises a synthetic hydrophilic polymer, such as polyethylene glycol, polyacrylic acid, or derivatives thereof (e.g. polymethylacrylic acid, polyacrylamide, or poly-N-substituted-acrylamide) .
  • Alginate is a suitable biodegradable polymeric material for use in the core and/or the shell.
  • Alginic acid is a naturally occurring polysaccharide, comprising a random block copolymer of ⁇ -1, 4-D-mannuronic acid (M unit) and ⁇ -1, 4-L-guluronic acid (G unit) .
  • M unit 4-D-mannuronic acid
  • G unit 4-L-guluronic acid
  • the M unit and G unit of an alginic acid are connected through 1, 4-glucosidic bond in the combination of M-M, G-G, or M-G to from a block copolymer.
  • Naturally occurring alginic acids has an empirical formula of (C 6 H 8 O 6 ) n , with a typical molecular weight of about 4 kDa-1500 kDa.
  • Alginic acid can be extracted from brown algae.
  • Alginate is a salt derived from alginic acid, including but not limited to, sodium alginate, calcium alginate, strontium alginate, and barium alginate.
  • G/M value refers to the molar ratio of ⁇ -1, 4-L-guluronic acid (G unit) and ⁇ -1, 4-D-mannuronic acid (M unit) within an alginate or oxidized alginate.
  • Oxidized alginate is the product of an oxidation reaction of alginate (such as sodium alginate) .
  • alginate such as sodium alginate
  • oxidation reactions convert the hydroxyl groups of a portion of the uronic acid units in alginate (such as sodium alginate) into aldehyde groups.
  • oxidized alginate such as oxidized sodium alginate and/or oxidized calcium alginate
  • the degradation rate of the core and/or shell can thereby be controlled by including oxidized alginate of a suitable oxidation level in the core and/or shell.
  • oxidation level refers to the molar percentage of oxidized uronic acid units among total uronic acid units in an alginic acid or alginate.
  • the degradation rate of a core or shell comprising alginate or oxidized alginate may further depend on the molecular mass and relative amount of the alginate or oxidized alginate, as well as the number of cells in the bio-block.
  • Alginate and oxidized alginate suitable for use in the bio-blocks have a molecular weight of about 4 kDa to about 1500 kDa.
  • the molecular weight of the alginate or oxidized alginate in the bio-blocks is about any of 4-10 kDa, 10-20 kDa, 20-30 kDa, 30-40 kDa, 40-50 kDa, 50-60 kDa, 60-70 kDa, 70-80 kDa, 80-90 kDa, 90-100 kDa, 100-200kDa, 200-300 kDa, 300-400 kDa, 400-500 kDa, 500-600 kDa, 700-800 kDa, 800-900 kDa, 900-1000 kDa, 1100-1200 kDa, 1200-1300 kDa, 1300-1400 kDa, or 1400-1500 kDa.
  • Alginate and oxidized alginate suitable for use in the bio-blocks have a G/M value of about 0.2 to about 5.
  • the G/M value of the alginate or oxidized alginate in the bio-blocks is about any of 0.2-0.3, 0.3-0.4, 0.4-0.5, 0.5-0.6, 0.6-0.7, 0.7-0.8, 0.8-0.9, 0.9-1.0, 1.0-1.5, 1.5-2.0, 2.0-2.5, 2.5-3.0, 3.0-3.5, 3.5-4.0, 4.0-4.5, or 4.5-5.0.
  • the G/M value of the alginate or oxidized alginate in the bio-blocks is about 0.2-2.5.
  • the alginate or oxidized alginate has a viscosity of about 100-3000 mPa ⁇ s. In some embodiments, the alginate or oxidized alginate has a viscosity of about any of 100-200, 200-300, 300-400, 400-500, 500-600, 600-700, 700-800, 800-900, 900-1000, 1000-1100, 1100-1200, 1200-1300, 1300-1400, 1400-1500, 1500-1600, 1600-1700, 1700-1800, 1800-1900, 1900-2000, 2000-2100, 2100-2200, 2200-2300, 2300-2400, 2400-2500, 2500-2600, 2600-2700, 2700-2800, 2800-2900, or 2900-3000 mPa ⁇ s. In some embodiments, the alginate or oxidized alginate has a viscosity of about 200-2000 mPa ⁇ s.
  • Suitable oxidation level of the oxidized alginate for use in the bio-blocks is about 1%to about 40%.
  • the oxidation level of the oxidized alginate in the bio-blocks is about any one of 1-2%, 2-3%, 3-4%, 4-5%, 5-6%, 6-7%, 7-8%, 8-9%, 9-10%, 11-12%, 12-13%, 13-14%, 14-15%, 15-16%, 16-17%, 17-18%, 18-19%, 19-20%, 20-25%, 25-30%, 30-35%, or 35-40%.
  • the oxidation level of the oxidized alginate in the bio-blocks is about any one of 2.5-4.4%, 4.4-8.8%, 8.8%-17.6%, or 17.6-22%.
  • Oxidized alginate may be obtained from oxidation reactions of alginate, for example, by reacting alginate salt with sodium periodate or other oxidative agents known in the art.
  • the oxidized alginate is obtained from oxidation reaction of an alginate obtained form an algae, such as brown algae, for example, kelp and Sargassum.
  • the biodegradable polymeric material (such as the biodegradable polymeric shell material or the biodegradable polymeric core material) comprises a mixture of alginate and oxidized alginate.
  • the percentage (by weight) of oxidized alginate in the mixture of alginate and oxidized alginate is at least about any one of 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, or more.
  • the percentage of oxidized alginate in the mixture of alginate and oxidized alginate is any one of about 1%to about 5%, about 5%to about 10%, about 10%to about 20%, about 20%to about 30%, about 30%to about 40%, about 40%to about 50%, about 50%to about 60%, about 60%to about 70%, about 70%to about 80%, about 80%to about 90%, about 90%to about 100%, about 1%to about 10%, about 20%to about 40%, about 40%to about 60%, about 1%to about 50%, about, about 25%to about 50%, about 50%to about 75%, about 75%to about 100%, about 40%to about 60%, about 60%to about 80%, about 80%to about 100%, or about 50%to about 100%.
  • the ratio between the oxidized alginate and alginate is at least about any one of 1: 10, 1: 9, 1: 8, 1: 7, 1: 6, 1: 5, 1: 4, 1: 3, 1: 2, 1: 1, 2: 1, 3: 1, 4: 1, 5: 1, 6: 1, 7: 1, 8: 1, 9: 1, 10: 1, or more.
  • the ratio between the oxidized alginate and alginate is any one of about 1: 10 to about 1: 9, about 1: 9 to about 1: 8, about 1: 8 to about 1: 7, about 1: 7 to about 1: 6, about 1: 6 to about 1: 5 about 1: 5 to about 1: 4 about 1: 4 to about 1: 3, about 1: 3 to about 1: 2, about 1: 2 to about 1: 1, about 1: 1 to about 2: 1, about 2: 1 to about 3: 1, about 3: 1 to about 4: 1, about 4: 1, to about 5: 1, about 5: 1 to about 6: 1, about 6: 1 to about 7: 1, about7: 1 to about 8: 1, about 8: 1 to about 9: 1, about 9: 1 to about 10: 1, about 1: 10 to about 10: 1, about 1: 8 to about 8: 1, about 1: 7 to about 7: 1, about 1: 6 to about 6: 1, about 1: 5 to about 5: 1, about 1: 4 to about 4: 1, about 1: 3 to about 3: 1, about 1: 2 to about 2 to about 3:
  • the bio-block comprises a single shell comprising a polymeric shell material (such biodegradable polymeric shell material) .
  • the bio-block comprises at least two shells each independently comprising a polymeric shell material (such biodegradable polymeric shell material) .
  • the at least two shells comprise the same polymeric shell material (such as biodegradable polymeric shell material) .
  • each of the at least two shells comprise a distinct polymeric shell material (such as biodegradable polymeric shell material) .
  • each of the at least two shells serve distinct functions.
  • Functions served by the shells include, but are not limited to, providing mechanical support, and/or providing a microenvironment (including, for example, nutrients and physical space) for the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) , and combinations thereof.
  • a microenvironment including, for example, nutrients and physical space
  • the endothelial cell such as MSC
  • tissue-specific cell such as hepatocyte or smooth muscle cell
  • the biodegradable polymeric shell material comprises a naturally occurring polymer or derivative thereof.
  • the naturally occurring polymer is selected from the group consisting of collagen (such as type I, type II or type III collagen) , fibrin, chitosan, alginate (such as sodium alginate or calcium alginate) , oxidized alginate, starch, hyaluronic acid, laminin, agarose, gelatin, glucan, elastin and combinations thereof.
  • the biodegradable polymeric shell material comprises a synthetic polymer.
  • the synthetic polymer is selected from the group consisting of polypohosphazene, polyacrylic acid, polymethacrylic acid, polyacrylic acid, polymethacrylic acid, acrylate copolymer (such as copolymer of acrylic acid and polymethacrylic acid) , polylactic acid (PLA) , polyglycolic acid (PGA) , poly- (lactide-coglycolide acid) (PLGA) , polyorthoester (POE) , polycaprolactone (PCL) , polyhydroxyrate (PHB) , polyamino acid (such as polylysine) , degradable polyurethane, copolymers thereof, and combinations thereof.
  • the biodegradable polymeric shell material comprises alginate, oxidized alginate, or combination thereof.
  • the percentage of the alginate, oxidized alginate, or combination thereof in the biodegradable polymeric shell material is at least about any one of 1%, 1.25%, 1.5%, 2%, 2.5%, 3%, 4%, 5%, 7.5%, 10%, 15%, 20%, or 25%.
  • the percentage of the alginate, oxidized alginate, or combination thereof in the biodegradable polymeric core material is about any one of 1%-1.25%, 1.25%-1.5%, 1.5%-2%, 2%-3%, 3%-4%, 4%-5%, 5%-6%, 6%-7%, 7%-8%, 8%-9%, 9%-10%, 1%-1.5%, 1%-2%, 1-2.5%, 1%-5%, 5-10%, 10%-15%, 15%-20%, 20%-25%, or 1%-25%.
  • the shell comprises oxidized alginate. In some embodiments, the shell comprises about 1-25%oxidized alginate, such as about any of 1-2%, 2-3%, 3%-4%, 4%-5%, 5%-6%, 6%-7%, 7%-8%, 8%-9%, 9%-10%, 10%-15%, 15%-20%, or 20%-25%. In some embodiments, the shell comprises at least 4% (such as at least about any of 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, or 25%) oxidized alginate.
  • the shell comprises a mixture of alginate and oxidized alginate.
  • the weight ratio of the alginate to the oxidized alginate is about 1: 9 to about 9: 1, such as 1: 9, 2: 8, 3: 7, 4: 6, 5: 5, 6: 4, 7: 3, 8: 2 and 9: 1.
  • the weight ratio of the alginate to the oxidized alginate is any of about 1: 10 to about 1: 9, about 1: 9 to about 1: 8, about 1: 8 to about 1: 7, about 1: 7 to about 1: 6, about 1: 6 to about 1: 5 about 1: 5 to about 1: 4 about 1: 4 to about 1: 3, about 1: 3 to about 1: 2, about 1: 2 to about 1: 1, about 1: 1 to about 2: 1, about 2: 1 to about 3: 1, about 3: 1 to about 4: 1, about 4: 1, to about 5: 1, about 5: 1 to about 6: 1, about 6: 1 to about 7: 1, about7: 1 to about 8: 1, about 8: 1 to about 9: 1, about 9: 1 to about 10: 1, about 1: 10 to about 10: 1, about 1: 8 to about 8: 1, about 1: 7 to about 7: 1, about 1: 6 to about 6: 1, about 1: 5 to about 5: 1, about 1: 4 to about 4: 1, about 1: 3 to about 3: 1, about 1: 2 to about 3 to about 1
  • the percentage of oxidized alginate in the biodegradable polymeric shell material is at least about any one of 1%, 1.25%, 1.5%, 2%, 2.5%, 3%, 4%, 5%, 7.5%, 10%, 15%, 20%, or 25%.
  • the percentage of oxidized alginate in the biodegradable polymeric shell material is about any one of 1%-1.25%, 1.25%-1.5%, 1.5%-2%, 2%-3%, 3%-4%, 4%-5%, 5%-6%, 6%-7%, 7%-8%, 8%-9%, 9%-10%, 1%-1.5%, 1%-2%, 1-2.5%, 1%-5%, 5-10%, 10%-15%, 15%-20%, 20%-25%, or 1%-25%.
  • the percentage of alginate in the biodegradable polymeric shell material is at least about any one of 1%, 1.25%, 1.5%, 2%, 2.5%, 3%, 4%, 5%, 7.5%, 10%, 15%, 20%, or 25%. In some embodiments, the percentage of alginate in the biodegradable polymeric shell material is about any one of 1%-1.25%, 1.25%-1.5%, 1.5%-2%, 2%-3%, 3%-4%, 4%-5%, 5%-6%, 6%-7%, 7%-8%, 8%-9%, 9%-10%, 1%-1.5%, 1%-2%, 1-2.5%, 1%-5%, 5-10%, 10%-15%, 15%-20%, 20%-25%, or 1%-25%.
  • the biodegradable polymeric shell material is crosslinked. Crosslinking of the biodegradable polymeric shell material may enhance the elastic properties, mechanical strength, and stability of the core and/or shell comprising the biodegradable polymer. In some embodiments, the biodegradable polymeric shell material is crosslinked covalently. In some embodiments, the biodegradable polymeric shell material is crosslinked non-covalently (such as by formation of ionic bonds) . In some embodiments, the crosslinking is reversible. In some embodiment, the biodegradable polymeric shell material is crosslinked by oxidation, such as oxidation of disulfide bonds. In some embodiment, the biodegradable polymeric shell material is crosslinked by a chemical reaction.
  • the biodegradable polymeric shell material is crosslinked by a physical process, such as heating or cooling. In some embodiments, the biodegradable polymeric shell material is crosslinked by In some embodiments, biodegradable polymeric shell material (such as alginate or oxidized alginate) is crosslinked by a divalent ion, such as Ca 2+ , Sr 2+ , and Ba 2+ . In some embodiments, the shell is solidified by the crosslinking.
  • At least one shell is solidified, e.g., by crosslinking.
  • each shell is solidified, such as by crosslinking.
  • the outermost shell (such as only the outermost shell) is solidified.
  • the solidified (such as crosslinked) shell may have improved mechanical properties.
  • the biodegradable polymeric shell material further comprises a cation with a +2 charge, including, but not limited to, Ca 2+ , Ba 2+ and Sr 2+ .
  • the biodegradable polymeric shell material further comprises calcium (such as Ca 2+ ) .
  • the shell comprises calcium alginate.
  • the cation (such as Ca 2+ ) serves to crosslink the polymers in the biodegradable polymeric shell material.
  • the crosslinked polymers form a hydrogel.
  • crosslinking of the polymers using the cation (such as Ca 2+ ) yields favorable mechanical properties of the shell, such as increasing elasticity and hardness of the shell.
  • the biodegradable polymeric shell material comprises (including consists of or consists essentially of) a polyamino acid (such as polylysine) , such as polylysine.
  • the percentage of the polylysine in the biodegradable polymeric shell material is at least about any of 0.1%, 0.2%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.2%, 1.5%, 2%, 3%, 4%, 5%or more.
  • the percentage of the alginate in the biodegradable polymeric core material is about any one of 0.1%-0.2%, 0.2%-0.5%, 0.5%-0.6%, 0.6%-0.7%, 0.7%-0.8%, 0.8%-0.9%, 0.9%-1%, 1%-1.2%, 1.2%-1.5%, 1.5%-2%, 2%-3%, 3%-5%, 0.1%-1%, 1%-2%, or 0.1%-5%.
  • the percentage of polylysine in the biodegradable polymeric shell material is no more than about 5%.
  • the biodegradable polymeric shell material comprises a mixture of alginate and agarose.
  • the weight ratio of the alginate to the agarose depends on the actual application of the bio-block. In some embodiments, the weight ratio of the agarose to the alginate in the biodegradable polymeric shell material is at least about any of 1: 10, 1: 9, 1: 8, 1: 7, 1: 6, 1: 5, 1: 4, 1: 3, 1: 2, 1: 1, 2: 1, 3: 1, 4: 1, 5: 1, 6: 1, 7: 1, 8: 1, 9: 1, or 10: 1.
  • the weight ratio of the agarose to the alginate in the biodegradable polymeric shell material is any one of about 1: 10 to about 1: 9, about 1: 9 to about 1: 8, about 1: 8 to about 1: 7, about 1: 7 to about 1: 6, about 1: 6 to about 1: 5, about 1: 5 to about 1: 4, about 1: 4 to about 1: 3, about 1: 3 to about 1: 2, about 1: 2 to about 1: 1, about 1: 1 to about 2: 1, about 2: 1 to about 3: 1, about 3: 1 to about 4: 1, about 4: 1 to about 5: 1, about 5: 1 to about 6: 1, about 6: 1 to about 7: 1, about 7: 1 to about 8: 1, about 8: 1 to about 9: 1, about 9: 1to about 10: 1, about 1: 10 to about 1: 5, about 1: 5 to about 1: 1, about 1: 1 to about 5: 1, about 5: 1 to about 10: 1, about 1: 5 to about 5: 1, or about 1: 10 to about 10: 1.
  • the weight ratio of the agarose and the alginate in the biodegradable polymeric shell material is about 1: 4.
  • the percentage of the alginate in the biodegradable polymeric shell material is at least about any of 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 4%, 5%, 7.5%, or 10%.
  • the percentage of the alginate in the biodegradable polymeric shell material is about any one of 0.5%-1%, 1%-1.5%, 1.5%-2%, 2%-2.5%, 2.5%-3%, 3%-4%, 4%-5%, 5%-7.5%, 7.5%-10%, 0.5%-2%, 2%-3%, 1.5%-3%, 0.5-4%, 1%-5%, 5-10%or 0.5%-10%.
  • the percentage of alginate in the biodegradable polymeric core material is at least about 4% (including for example, at least about 5%, at least about 7.5%, or at least about 10%) .
  • the percentage of the agarose in the biodegradable polymeric shell material is at least about any of 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 4%, 5%, 7.5%, or 10%. In some embodiments, the percentage of the agarose in the biodegradable polymeric shell material is about any one of 0.5%-1%, 1%-1.5%, 1.5%-2%, 2%-2.5%, 2.5%-3%, 3%-4%, 4%-5%, 5%-7.5%, 7.5%-10%, 0.5%-2%, 2%-3%, 1.5%-3%, 0.5-4%, 1%-5%, 5-10%or 0.5%-10%.
  • the biodegradable polymeric shell material comprises a mixture of alginate (such as sodium alginate) and elastin.
  • the weight ratio of the alginate to the elastin depends on the actual application of the bio-block. In some embodiments, the weight ratio of the alginate to the elastin in the biodegradable polymeric shell material is at least about any of 50: 1, 100: 1, 200: 1, 300: 1, 400: 1, 500: 1, 600: 1, 700: 1, 800: 1, 900: 1, 1000: 1, 2000: 1, or 5000: 1.
  • the weight ratio of the alginate to the elastin in the biodegradable polymeric shell material is any of about 50: 1 to about 100: 1, about 100: 1 to about 200: 1, about 200: 1 to about 300: 1, about 300: 1 to about 400: 1, about 400: 1 to about 500: 1, about 500: 1 to about 600: 1, about 600: 1 to about 700: 1, about 700: 1 to about 800: 1, about 800: 1 to about 900: 1, about 900: 1 to about 1000: 1, about 1000: 1 to about 2000: 1, about 2000: 1 to about 5000: 1, about 50: 1 to about 300: 1, about 300: 1 to about 500: 1, about 500: 1 to about 1000: 1, about 800: 1 to about 5000: 1, about 400: 1 to about 600: 1, or about 200: 1 to about 800: 1.
  • the weight ratio of the alginate to the elastin in the biodegradable polymeric shell material is about 500: 1.
  • the percentage of the alginate in the biodegradable polymeric shell material is at least about any of 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 4%, 5%, 7.5%, or 10%.
  • the percentage of the alginate in the biodegradable polymeric shell material is about any of 0.5%-1%, 1%-1.5%, 1.5%-2%, 2%-2.5%, 2.5%-3%, 3%-4%, 4%-5%, 5%-7.5%, 7.5%-10%, 0.5%-2%, 2%-3%, 1.5%-3%, 0.5-4%, 1%-5%, 5-10%or 0.5%-10%.
  • the percentage of alginate in the biodegradable polymeric core material is at least about 4% (including for example, at least about 5%, at least about 7.5%, or at least about 10%) .
  • the percentage of elastin in the biodegradable polymeric shell material is at least about any of 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.1%, 0.15%, 0.2%, or 0.5%.
  • the percentage of elastin in the biodegradable polymeric shell material is about any of 0.01%-0.02%, 0.02%-0.03%, 0.03%-0.04%, 0.04%-0.05%, 0.05%-0.06%, 0.06%-0.07%, 0.07%-0.08%, 0.08%-0.1%, 0.1%-0.15%, 0.15%-0.2%, 0.2%, 0.2%-0.5%, 0.01%-0.03%, 0.03%-0.05%, 0.05%-0.08%, 0.08%-0.15%, 0.01%-0.05%, 0.05%-0.1%, 0.03%-0.07%, 0.04%-0.06%, 0.01%-0.1%, 0.1%-0.5%, or 0.01%-0.5%.
  • the biodegradable polymeric shell material comprises alginate (such as sodium alginate or calcium alginate) and gelatin.
  • the weight ratios of the alginate, and the gelatin depend on the actual application of the bio-block. In some embodiments, the weight ratio of the alginate to the gelatin in the biodegradable polymeric shell material is at least about any of 10: 1, 9: 1, 8: 1, 7: 1, 6: 1, 5: 1, 4: 1, 3: 1, 2: 1, 1: 1, 1: 2, 1: 3, 1: 4, 1: 5, 1: 6, 1: 7, 1: 8, 1: 9, or 1: 10.
  • the weight ratio of the alginate to the gelatin in the biodegradable polymeric shell material is about any of 10: 1 to about 9: 1, about 9: 1 to about 8: 1, about 8: 1 to about 7: 1, about 7: 1 to about 6: 1, about 6: 1 to about 5: 1, about 5: 1 to about 4: 1, about 4: 1 to about 3: 1, about 3: 1 to about 2: 1, about 2: 1 to about 1: 1, about 1: 1 to about 1: 2, about 1: 2 to about 1: 3, about 1: 3 to about 1: 4, about 1: 4 to about 1: 5, about 1: 5 to about 1: 6, about 1: 6 to about 1: 7, about 1: 7 to about 1: 8, about 1: 8 to about 1: 9, about 1: 9 to about 1: 10, about 10: 1 to about 5: 1, about 5: 1 to about 1: 1, about 1: 1 to about 1: 5, about 1: 5 to about 1: 10, about 2: 1 to about 1: 2, about 4: 1 to about 1: 4, or about 10: 1 to about 1:
  • the weight ratio of the gelatin and the alginate in the biodegradable polymeric shell material is about 15: 85.
  • the percentage of the alginate in the biodegradable polymeric shell material is at least about any of 0.1%, 0.5%, 1%, 1.25%, 1.5%, 2%, 3%, 4%, 5%, 7.5%, or 10%.
  • the percentage of alginate in the biodegradable polymeric shell material is about any of 0.1%-0.5%, 0.5%-1%, 1%-1.25%, 1.25%-1.5%, 1.5%-2%, 2%-3%, 3%-4%, 4%-5%, 5%-7.5%, 7.5%-10%, 0.1%-1%, 1%-1.5%, 1%-2%, 0.5-2.5%, 1%-3%, 5-10%or 0.5%-5%.
  • the percentage of alginate in the biodegradable polymeric core material is at least about 4% (including for example, at least about 5%, at least about 7.5%, or at least about 10%) .
  • the percentage of gelatin in the biodegradable polymeric shell material is at least about any of 0.1%, 0.5%, 1%, 1.25%, 1.5%, 2%, 3%, 4%, 5%, 7.5%, or 10%. In some embodiments, the percentage of gelatin in the biodegradable polymeric shell material is about any of 0.1%-0.5%, 0.5%-1%, 1%-1.25%, 1.25%-1.5%, 1.5%-2%, 2%-3%, 3%-4%, 4%-5%, 5%-7.5%, 7.5%-10%, 0.1%-1%, 1%-1.5%, 1%-2%, 0.5-2.5%, 1%-3%, 5-10%or 0.5%-5%.
  • the biodegradable polymeric shell material comprises alginate (such as sodium alginate) , gelatin, and elastin.
  • alginate such as sodium alginate
  • gelatin such as sodium alginate
  • elastin The weight ratios of the alginate, the gelatin and the elastin depend on the actual application of the bio-block. In some embodiments, the weight ratio of the alginate to the gelatin in the biodegradable polymeric shell material is about any of 10: 1, 9: 1, 8: 1, 7: 1, 6: 1, 5: 1, 4: 1, 3: 1, 2: 1, 1: 1, 1: 2, 1: 3, 1: 4, 1: 5, 1: 6, 1: 7, 1: 8, 1: 9, or 1: 10.
  • the weight ratio of the alginate to the gelatin in the biodegradable polymeric shell material is about any of 10: 1 to about 9: 1, about 9: 1 to about 8: 1, about 8: 1 to about 7: 1, about 7: 1 to about 6: 1, about 6: 1 to about 5: 1, about 5: 1 to about 4: 1, about 4: 1 to about 3: 1, about 3: 1 to about 2: 1, about 2: 1 to about 1: 1, about 1: 1 to about 1: 2, about 1: 2 to about 1: 3, about 1: 3 to about 1: 4, about 1: 4 to about 1: 5, about 1: 5 to about 1: 6, about 1: 6 to about 1: 7, about 1: 7 to about 1: 8, about 1: 8 to about 1: 9, about 1: 9 to about 1: 10, about 10: 1 to about 5: 1, about 5: 1 to about 1: 1, about 1: 1 to about 1: 5, about 1: 5 to about 1: 10, about 2: 1 to about 1: 2, about 4: 1 to about 1: 4, or about 10: 1 to about 1:
  • the weight ratio of the alginate to the elastin in the biodegradable polymeric shell material is at least about any of 1000: 1, 500: 1, 400: 1, 300: 1, 250: 1, 200: 1, 100: 1, 50: 1, or 10: 1. In some embodiments, the weight ratio of the alginate to the elastin in the biodegradable polymeric shell material is about any of 10: 1 to about 50: 1, about 50: 1 to about 100: 1, about 100: 1 to about 200: 1, about 200: 1 to about 250: 1, about 250: 1 to about 300: 1, about 300: 1 to about 400: 1, about 400: 1 to about 500: 1, about 500: 1 to about 1000: 1, about 10: 1 to about 100: 1, about 100: 1 to about 200: 1, about 200: 1 to about 300: 1, about 300: 1 to about 400: 1, about 400: 1 to about 1000: 1, or about 100: 1 to about 500: 1.
  • the weight ratio of the gelatin to the elastin in the biodegradable polymeric shell material is at least about any of 1000: 1, 500: 1, 400: 1, 300: 1, 250: 1, 200: 1, 100: 1, 50: 1, or 10: 1.
  • the weight ratio of the gelatin to the elastin in the biodegradable polymeric shell material is about any of 10: 1 to about 50: 1, about 50: 1 to about 100: 1, about 100: 1 to about 200: 1, about 200: 1 to about 250: 1, about 250: 1 to about 300: 1, about 300: 1 to about 400: 1, about 400: 1 to about 500: 1, about 500: 1 to about 1000: 1, about 10: 1 to about 100: 1, about 100: 1 to about 200: 1, about 200: 1 to about 300: 1, about 300: 1 to about 400: 1, about 400: 1 to about 1000: 1, or about 100: 1 to about 500: 1.
  • the weight ratio of the gelatin, the alginate and the elastin in the biodegradable polymeric shell material is about 250: 250: 1.
  • the percentage of the alginate in the biodegradable polymeric shell material is at least about any of 0.1%, 0.5%, 1%, 1.25%, 1.5%, 2%, 3%, 4%, 5%, 7.5%, or 10%.
  • the percentage of alginate in the biodegradable polymeric shell material is about any of 0.1%-0.5%, 0.5%-1%, 1%-1.25%, 1.25%-1.5%, 1.5%-2%, 2%-3%, 3%-4%, 4%-5%, 5%-7.5%, 7.5%-10%, 0.1%-1%, 1%-1.5%, 1%-2%, 0.5-2.5%, 1%-3%, 5-10%or 0.5%-5%.
  • the percentage of alginate in the biodegradable polymeric core material is at least about 4% (including for example, at least about 5%, at least about 7.5%, or at least about 10%) .
  • the percentage of gelatin in the biodegradable polymeric shell material is at least about any of 0.1%, 0.5%, 1%, 1.25%, 1.5%, 2%, 3%, 4%, 5%, 7.5%, or 10%. In some embodiments, the percentage of gelatin in the biodegradable polymeric shell material is about any of 0.1%-0.5%, 0.5%-1%, 1%-1.25%, 1.25%-1.5%, 1.5%-2%, 2%-3%, 3%-4%, 4%-5%, 5%-7.5%, 7.5%-10%, 0.1%-1%, 1%-1.5%, 1%-2%, 0.5-2.5%, 1%-3%, 5-10%or 0.5%-5%.
  • the percentage of elastin in the biodegradable polymeric shell material is at least about any of 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.1%, 0.15%, 0.2%, or 0.5%.
  • the percentage of elastin in the biodegradable polymeric shell material is about any of 0.01%-0.02%, 0.02%-0.03%, 0.03%-0.04%, 0.04%-0.05%, 0.05%-0.06%, 0.06%-0.07%, 0.07%-0.08%, 0.08%-0.1%, 0.1%-0.15%, 0.15%-0.2%, 0.2%, 0.2%-0.5%, 0.01%-0.03%, 0.03%-0.05%, 0.05%-0.08%, 0.08%-0.15%, 0.01%-0.05%, 0.05%-0.1%, 0.03%-0.07%, 0.04%-0.06%, 0.01%-0.1%, 0.1%-0.5%, or 0.01%-0.5%.
  • the shell provides mechanical support and/or protection to the core, including the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) .
  • the core including the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) .
  • the shell degrades completely within no more than about 28 days. In some embodiments, the shell degrades completely within no more than about any of 21 days, 14 days, 12 days, 10 days, 9 days, 8 days, 7 days, 6 days, 5 days, 4 days, 3 days, or 2 days. In some embodiments, the shell degrades completely within about any of 2-5 days, 2-6 days, 2-8 days, 2-10 days, 2-12 days, 2-14 days, 14-21 days, 21-28 days, 7-14 days, 5-10 days, or 2-28 days.
  • the shell has a viscosity of about 100-3000 mPa ⁇ s. In some embodiments, the shell has a viscosity of about any one of 100-200, 200-300, 300-400, 400-500, 500-600, 600-700, 700-800, 800-900, 900-1000, 1000-1100, 1100-1200, 1200-1300, 1300-1400, 1400-1500, 1500-1600, 1600-1700, 1700-1800, 1800-1900, 1900-2000, 2000-2100, 2100-2200, 2200-2300, 2300-2400, 2400-2500, 2500-2600, 2600-2700, 2700-2800, 2800-2900, or 2900-3000 mPa ⁇ s. In some preferred embodiments, the shell has a viscosity of about 200-2000 mPa ⁇ s.
  • the shell has a thickness of about any of 0.1, 0.5, 1, 2, 5, 10, 15, 20, 25, 30, 50, 100, or 200 ⁇ m. In some embodiments, the shell has a thickness of about any of 0.1-0.5, 0.5-1, 1-2, 2-5, 5-10, 10-15, 15-20, 20-25, 25-30, 30-50, 0.1-1, 1-5, 1-10, 5-10, 10-20, 10-30, 5-20, 1-20, 0.1-50, 1-20, 1-100, or 1-200 ⁇ m. In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m, such as about 1 ⁇ m to about 20 ⁇ m.
  • the hardness and elasticity of the bio-block are typically reflective of the hardness and elasticity of the shell of the bio-block.
  • the capacity of mechanical protection provided by the shell is dependent on the hardness and elasticity of the shell or the bio-block, which can be controlled by adjusting the composition (such as the biodegradable polymeric shell material, including components and relative amount of each component) of the shell.
  • the bio-block or the shell has a hardness of at least about any of 0.01, 0.05, 0.1, 0.15, 0.18, 0.2, 0.22, 0.25, 0.3, or 0.4 GPa.
  • the bio-block or the shell has a hardness of about any one of 0.01-0.05, 0.05-0.1, 0.1-0.15, 0.14-0.16, 0.16-0.18, 0.18-0.2, 0.2-0.22, 0.2-0.3, 0.3-0.4, 0.01-0.4, 0.01-1, 0.1-0.2, 0.2-0.4, 0.15-0.25, 0.04-0.22, 0.01-0.02, 0.02-0.03, 0.03-0.04, 0.04-0.05, 0.05-0.06, 0.06-0.07, 0.07-0.08, 0.08-0.09, 0.09-0.1, 0.15-0.2, 0.05-0.15, or 0.06-0.1 GPa.
  • the bio-block or the shell has a modulus of elasticity of at least about any of 0.01, 0.1, 0.5, 1, 1.5, 2, 2.5, 2.8, 3, 3.2, 3.4, 3.6, 4, 10, 20, 50, 75, or 100 MPa.
  • the bio-block or the shell has an elasticity of about any one of 0.01-0.05, 0.05-0.1, 0.1-0.5, 0.5-0.8, 0.8-1, 0.5-1, 1-1.2, 1.2-1.4, 1.4-1.6, 1.6-1.8, 1.8-2, 1-1.5, 1.5-2, 2-2.4, 2.4-2.8, 2.8-3, 3-3.2, 3.2-3.4, 3.4-3.6, 3.6-4, 4-10, 10-20, 20-30, 30-40, 40-50, 20-50, 50-75, 75-100, 50-80, 80-100, 0.5-4, 1-1.5, 1.5-2, 2-3, 0.8-1.6, 1.4-2.4, 0.8-3.2, 1-100, 10-100, 0.5-6, 1.5-2.5, 2.5-3, 2.8-3.2, 3.2-3.6, 2.9-3.6, 0.01-1, 1-5, 5-10, 10-50, 50-100, 0.01-10, 0.01-25, 0.01-50, 0.01-75, 1-25, 1-50, 10-50, 10-75, or 0.01-100 MPa.
  • the bio-block has mechanical strength to endure elastic deformation during three-dimensional deposition. In some embodiments, the bio-block endures elastic deformation during handling and tissue-manufacturing (such as bioprinting) process. In some embodiments, the bio-block reduces mechanical damage of the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) in the bio-block during bioprinting by at least about any of 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, 70%, 80%, or 90%compared to bioprinting of the same type of cell (s) using the same bioprinter and under similar conditions.
  • tissue-manufacturing such as bioprinting
  • the bio-block reduces heating of the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) in the bio-block during bioprinting by at least about any of 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, 70%, 80%, or 90%compared to bioprinting of the same type of cells using the same bioprinter and under similar conditions.
  • the tissue-specific cell such as hepatocyte or smooth muscle cell
  • the bio-block preserves activities (such as metabolism, proliferation, differentiation, migration, and/or secretion) of the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) in the bio-block during bioprinting. In some embodiments, more than about any of 80%, 85%, 87.5%, 90%, 92.5%, 95%, or 98%of the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) in the bio-block survives about 24 hours after bioprinting.
  • more than about 90%of the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) in the bio-block survives at least about any of 3 hours, 6 hours, 12 hours, 24 hours, 2 days, 4 days, or 1 week after bioprinting. In some embodiments, more than about any of 80%, 85%, 87.5%, 90%, 92.5%, 95%, or 98%of the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) in the bio-block is capable of proliferation about 24 hours after bioprinting.
  • more than about any of 80%, 85%, 87.5%, 90%, 92.5%, 95%, or 98%of the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) in the bio-block is capable of differentiation about 24 hours after bioprinting. In some embodiments, more than about any of 80%, 85%, 87.5%, 90%, 92.5%, 95%, or 98%of the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) in the bio-block has normal metabolism about 24 hours after bioprinting.
  • more than about any of 80%, 85%, 87.5%, 90%, 92.5%, 95%, or 98%of the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) in the bio-block is capable of migration about 24 hours after bioprinting. In some embodiments, more than about any of 80%, 85%, 87.5%, 90%, 92.5%, 95%, or 98%of the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) in the bio-block is capable of secretion about 24 hours after bioprinting.
  • the bio-block comprises a single core comprising a polymeric core material (such biodegradable polymeric core material) .
  • the bio-block comprises at least two cores each independently comprising a polymeric core material (such biodegradable polymeric core material) .
  • the bio-block comprises at least two cores.
  • the at least two cores comprise the same polymeric core material (such as biodegradable polymeric core material) .
  • each of the at least two cores comprise a distinct polymeric core material (such as biodegradable polymeric core material) .
  • the biodegradable polymeric core material comprises a naturally occurring polymer or derivative thereof.
  • the naturally occurring polymer is selected from the group consisting of collagen (such as type I, type II or type III collagen) , fibrin, chitosan, alginate (such as sodium alginate or calcium alginate) , oxidized alginate, starch, hyaluronic acid, laminin, agarose, gelatin, glucan, elastin and combinations thereof.
  • the biodegradable polymeric core material comprises a synthetic polymer.
  • the synthetic polymer is selected from the group consisting of polypohosphazene, polyacrylic acid, polymethacrylic acid, polyacrylic acid, polymethacrylic acid, acrylate copolymer (such as copolymer of acrylic acid and polymethacrylic acid) , polylactic acid (PLA) , polyglycolic acid (PGA) , poly- (lactide-coglycolide acid) (PLGA) , polyorthoester (POE) , polycaprolactone (PCL) , polyhydroxyrate (PHB) , polyamino acid (such as polylysine) , degradable polyurethane, copolymers thereof, and combinations thereof.
  • the biodegradable polymeric core material comprises (including consists of or consists essentially of) alginate (such as sodium alginate) .
  • the biodegradable polymeric core material comprises (including consists of or consists essentially of) type I collagen.
  • biodegradable polymeric core material comprises (including consists of or consists essentially of) laminin.
  • the biodegradable polymeric core material comprises (including consists of or consists essentially of) starch.
  • the biodegradable polymeric core material comprises (including consists of or consists essentially of) degradable polyurethane.
  • the bio-block comprises a core comprising alginate (such as sodium alginate, for example, no more than about 2%) and a cell, and a shell comprising alginate (such as calcium alginate, such as at least about 4%) .
  • the bio-block comprises a core comprising type I collagen (such as at least about 0.4%) , alginate (such as sodium alginate, for example, no more than about 2.5%or 2%) and a cell, and a shell comprising alginate (such as calcium alginate, such as at least about 2.5%or 4%) and elastin.
  • the bio-block comprises a core comprising alginate (such as sodium alginate, for example, no more than about 2%) and a cell, and a shell comprising polylysine (such as at least about 1%) .
  • the bio-block comprises a core comprising starch (such as at least about 50%) and a cell, and a shell comprising alginate (such as calcium alginate, for example, at least about 4%) .
  • the bio-block comprises a core comprising starch (such as at least about 50%) and a cell, and a shell comprising oxidized alginate (such as oxidized calcium alginate, for example, at least about 4%) .
  • the bio-block comprises a core comprising starch (such as at least about 50%) and a cell, and a shell comprising alginate (such as calcium alginate) and oxidized alginate (such as oxidized calcium alginate) .
  • the bio-block comprises a core comprising type I collagen (such as at least about 0.4%) and a cell, and a shell comprising polylysine (such as at least about 1%) .
  • the bio-block comprises a core comprising type I collagen (such as at least about 0.4%) and a cell, and a shell comprising alginate (such as calcium alginate, for example, at least about 0.4%) .
  • the bio-block comprises a core comprising type I collagen (such as at least about 0.4%) and a cell, and a shell comprising oxidized alginate (such as oxidized calcium alginate, for example, at least about 0.4%) .
  • the bio-block comprises a core comprising type I collagen (such as at least about 0.4%) and a cell, and a shell comprising alginate (such as calcium alginate) and oxidized alginate (such as oxidized calcium alginate) .
  • the bio-block comprises a core comprising polyurethane (such as at least about 40%) and a cell, and a shell comprising alginate (such as calcium alginate, for example, at least about 4%) .
  • the bio-block comprises a core comprising polyurethane (such as at least about 40%) and a cell, and a shell comprising oxidized alginate (such as oxidized calcium alginate, for example, at least about 4%) .
  • the bio-block comprises a core comprising polyurethane (such as at least about 40%) and a cell, and a shell comprising alginate (such as calcium alginate) and oxidized alginate (such as oxidized calcium alginate) .
  • the bio-block comprises a core comprising polyurethane (such as at least about 40%) and a cell, and a shell comprising alginate (such as calcium alginate) and gelatin.
  • the bio-block comprises a core comprising laminin and a cell, and a shell comprising alginate (such as calcium alginate) and agarose.
  • the biodegradable polymeric core material comprises alginate, oxidized alginate, or combination thereof.
  • the percentage of the alginate, oxidized alginate, or combination thereof in the biodegradable polymeric core material is at least about any of 0.1%, 0.5%, 1%, 1.25%, 1.5%, 2%, 3%, 4%, 5%, 7.5%, or 10%.
  • the percentage of the alginate, oxidized alginate, or combination thereof in the biodegradable polymeric core material is about any of 0.1%-0.5%, 0.5%-1%, 1%-1.25%, 1.25%-1.5%, 1.5%-2%, 2%-3%, 3%-4%, 4%-5%, 5%-7.5%, 7.5%-10%, 0.1%-1%, 1%-1.5%, 1%-2%, 0.5-2.5%, 1%-3%, 5-10%or 0.5%-5%.
  • the percentage of the alginate, oxidized alginate, or combination thereof in the biodegradable polymeric core material is no more than about 2.5% (including for example, no more than about any of 2%, 1.5%, 1%, or 0.5%) .
  • the biodegradable polymeric core material comprises (such as consists essentially of) type I collagen.
  • the concentration of the type I collagen in the biodegradable polymeric core material is at least about any of 0.1 mg/mL, 0.5 mg/mL, 1 mg/mL, 1.5 mg/mL, 2 mg/mL, 3 mg/mL, 4 mg/mL, 5 mg/mL, 10 mg/mL or more.
  • the concentration of the type I collagen in the biodegradable polymeric core material is about any one of 0.1-0.5, 0.5-1, 1-1.5, 1-2, 2-3, 3-4, 4-5, 5-10, 0.1-2, 0.1-5, or 1-10 mg/mL.
  • the weight percentage of type I collagen in the biodegradable polymeric core material is at least about any of 0.01%, 0.05%, 0.1%, 0.125%, 0.15%, 0.175%, 0.2%, 0.25%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 2%, 3%, 4%, 5%, 10%, or more.
  • the percentage of type I collagen in the biodegradable polymeric core material is about any of 0.01%-0.05%, 0.05%-0.1%, 0.1%-0.125%, 0.125%-0.15%, 0.15%-0.175%, 0.175%-0.2%, 0.2%-0.25%, 0.25%-0.3%, 0.3%-0.4%, 0.4%-0.5%, 0.5%-0.6%, 0.6%-0.7%, 0.7%-0.8%, 0.8%-0.9%, 0.2%-0.8%, 0.5%-1%, 1%-2%, 2%-3%, 3%-4%, 4%-5%, 0.01%-0.1%, 0.1%-0.2%, 0.2%-0.5%, 0.1%-0.5%, 0.1%-1%, 0.05%-5%, or 5%-10%.
  • the biodegradable polymeric core material comprises a mixture of type I collagen and alginate (such as sodium alginate) .
  • the weight ratio between the type I collagen to the alginate depends on the actual application of the bio-block. In some embodiments, the weight ratio between the type I collagen to the alginate in the biodegradable polymeric core material is at least about any of 50: 1, 30: 1, 20: 1, 10: 1, 9: 1, 8: 1, 6: 1, 4: 1, 2: 1, 1: 1, 1: 2, 1: 4, 1: 6, 1: 8, 3: 25, 1: 9, 1: 10, 1: 20, 1: 30, or 1: 50.
  • the weight ratio between the type I collagen to the alginate in the biodegradable polymeric core material is any of about 50: 1 to about 30: 1, about 30: 1 to about 20: 1, about 20: 1 to about 10: 1, about 10: 1 to about 9: 1, about 9: 1 to about 8: 1, about 8: 1 to about 6: 1, about 6: 1 to about 4: 1, about 4: 1 to about 2: 1, about 2: 1 to about 1: 1, about 1: 1 to about 1: 2, about 1: 2 to about 1: 4, about 1: 4 to about 1: 6, about 1: 6 to about 1: 8, about 1: 8 to about 1: 9, about 1: 9 to about 1: 10, about 1: 10 to about 1: 20, about 1: 20 to about 1: 30, about 1: 30 to about 1: 50, about 10: 1 to about 5: 1, about 5: 1 to about 1: 1, about 1: 1 to about 1: 5, about 1: 5 to about 1: 10, about 1: 7 to about 1: 10, or about 1: 8 to about 1: 9.
  • the percentage of type I collagen in the biodegradable polymeric core material is at least about any of 0.01%, 0.05%, 0.1%, 0.125%, 0.15%, 0.175%, 0.2%, 0.25%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 2%, 3%, 4%, 5%, 10%, or more.
  • the percentage of type I collagen in the biodegradable polymeric core material is about any of 0.01%-0.05%, 0.05%-0.1%, 0.1%-0.125%, 0.125%-0.15%, 0.15%-0.175%, 0.175%-0.2%, 0.2%-0.25%, 0.25%-0.3%, 0.3%-0.4%, 0.4%-0.5%, 0.5%-0.6%, 0.6%-0.7%, 0.7%-0.8%, 0.8%-0.9%, 0.2%-0.8%, 0.5%-1%, 1%-2%, 2%-3%, 3%-4%, 4%-5%, 0.01%-0.1%, 0.1%-0.2%, 0.2%-0.5%, 0.1%-0.5%, 0.1%-1%, 0.05%-5%, or 5%-10%.
  • the percentage of the alginate in the biodegradable polymeric core material is at least about any of 0.1%, 0.5%, 1%, 1.25%, 1.5%, 2%, 3%, 4%, 5%, 7.5%, or 10%. In some embodiments, the percentage of the alginate in the biodegradable polymeric core material is about any of 0.1%-0.5%, 0.5%-1%, 1%-1.25%, 1.25%-1.5%, 1.5%-2%, 2%-3%, 3%-4%, 4%-5%, 5%-7.5%, 7.5%-10%, 0.1%-1%, 1%-1.5%, 1%-2%, 0.5-2.5%, 1%-3%, 5-10%or 0.5%-5%. In some embodiments, the percentage of alginate in the biodegradable polymeric core material is no more than about 2.5% (including for example, no more than about any of 2%, 1.5%, 1%, or 0.5%) .
  • the biodegradable polymeric core material comprises type I collagen and laminin.
  • the weight ratio of the type I collagen to the laminin depends on the actual application of the bio-block. In some embodiments, the weight ratio of the type I collagen to the laminin in the biodegradable polymeric core material is at least about any of 50: 1, 30: 1, 20: 1, 10: 1, 9: 1, 8: 1, 6: 1, 4: 1, 2: 1, 1: 1, 1: 2, 1: 4, 1: 6, 1: 8, 1: 9, 1: 10, 1: 20, 1: 30, or 1: 50.
  • the weight ratio of the type I collagen to the laminin in the biodegradable polymeric core material is any of about 50: 1 to about 30: 1, about 30: 1 to about 20: 1, about 20: 1 to about 10: 1, about 10: 1 to about 9: 1, about 9: 1 to about 8: 1, about 8: 1 to about 6: 1, about 6: 1 to about 4: 1, about 4: 1 to about 2: 1, about 2: 1 to about 1: 1, about 1: 1 to about 1: 2, about 1: 2 to about 1: 4, about 1: 4 to about 1: 6, about 1: 6 to about 1: 8, about 1: 8 to about 1: 9, about 1: 9 to about 1: 10, about 1: 10 to about 1: 20, about 1: 20 to about 1: 30, about 1: 30 to about 1: 50, about 10: 1 to about 5: 1, about 5: 1 to about 1: 1, about 1: 1 to about 1: 5, about 1: 5 to about 1: 10, about 1: 7 to about 1: 10, or about 1: 8 to about 1: 9.
  • the percentage of type I collagen in the biodegradable polymeric core material is at least about any of 0.01%, 0.05%, 0.1%, 0.125%, 0.15%, 0.175%, 0.2%, 0.25%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 2%, 3%, 4%, 5%, 10%, or more.
  • the percentage of type I collagen in the biodegradable polymeric core material is about any of 0.01%-0.05%, 0.05%-0.1%, 0.1%-0.125%, 0.125%-0.15%, 0.15%-0.175%, 0.175%-0.2%, 0.2%-0.25%, 0.25%-0.3%, 0.3%-0.4%, 0.4%-0.5%, 0.5%-0.6%, 0.6%-0.7%, 0.7%-0.8%, 0.8%-0.9%, 0.2%-0.8%, 0.5%-1%, 1%-2%, 2%-3%, 3%-4%, 4%-5%, 0.01%-0.1%, 0.1%-0.2%, 0.2%-0.5%, 0.1%-0.5%, 0.1%-1%, 0.05%-5%, or 5%-10%.
  • the percentage of the laminin in the biodegradable polymeric core material is at least about any of 0.1%, 0.5%, 1%, 1.25%, 1.5%, 2%, 3%, 4%, 5%, 7.5%, or 10%. In some embodiments, the percentage of the laminin in the biodegradable polymeric core material is about any of 0.1%-0.5%, 0.5%-1%, 1%-1.25%, 1.25%-1.5%, 1.5%-2%, 2%-3%, 3%-4%, 4%-5%, 5%-7.5%, 7.5%-10%, 0.1%-1%, 1%-1.5%, 1%-2%, 0.5-2.5%, 1%-3%, 5-10%or 0.5%-5%.
  • the biodegradable polymeric core material comprises starch.
  • the percentage of starch in the biodegradable polymeric core material is at least about any of 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or more.
  • the percentage of starch in the biodegradable polymeric core material is about any of 5%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-80%, 10%-80%, 20%-70%, 30%-60%, or 40%-60%.
  • the biodegradable polymeric core material comprises polyurethane.
  • the percentage of polyurethane in the biodegradable polymeric core material is at least about any of 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or more. In some embodiments, the percentage of polyurethane in the biodegradable polymeric core material is about any of 5%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 10%-80%, 20%-70%, 30%-60%, or 40%-80%.
  • the bio-block including the shell and/or the core, provides a suitable spatial structure for cell adhesion and spreading, as well as a microenvironment for the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) .
  • a microenvironment refers to the appropriate environment comprising a combination of suitable microenvironmental factors for a cell to carry out its life activities.
  • suitable microenvironmental factors include, but are not limited to, physical factors (e.g., physical space, mechanical strength, mechanical factors, temperature, humidity, osmotic pressure, etc. ) ; chemical factors (e.g., pH, ionic concentrations, etc.
  • the microenvironment may dynamically regulate one or more activities of the cell, including, but not limited to, proliferation, differentiation, migration, metabolism, and secretion.
  • the core provides a microenvironment (such as nutrients) for the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) .
  • the shell provides one or more microenvironmental factors to the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) .
  • the core provides one or more microenvironmental factors to the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) .
  • the shell and the core provide one or more microenvironmental factors to the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) .
  • the one or more microenvironmental factors comprise growth factors for the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) to grow and to differentiate.
  • the one or more microenvironmental factors comprise a structure and space for the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) to proliferate and to differentiate.
  • the one or more microenvironmental factors comprise physical factors (such as mechanical stimuli) for the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) to carry out its biological functions.
  • the one or more microenvironmental factors comprise feeder cells to facilitate or to regulate differentiation of the stem cell (such as MSC) .
  • the biodegradable polymeric core and/or shell material provides one or more microenvironmental factors (such as space, nutrients, ECM, etc. ) for the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) .
  • bio-blocks having a core consisting essentially of type I collagen provides a suitable microenvironment for the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) .
  • the core comprises an agent selected from the group consisting of nutrients, extracellular matrix, cell factors, pharmaceutically active agents, and combinations thereof.
  • the core comprises an agent that regulates (such as facilitates) cell proliferation, differentiation, migration, metabolism, secretion, or any combination thereof.
  • the cell factors regulate (such as facilitate) cell proliferation, differentiation, migration, metabolism, secretion, or any combination thereof.
  • the shell comprises an agent selected from the group consisting of nutrients, extracellular matrix, cell factors, pharmaceutically active agents, and combinations thereof.
  • the shell comprises an agent that regulates (such as facilitates) cell proliferation, differentiation, migration, metabolism, secretion, or any combination thereof.
  • the cell factors regulate (such as facilitate) cell proliferation, differentiation, migration, metabolism, secretion, or any combination thereof.
  • the agent is a protein. In some embodiments, the agent is a human protein. In some embodiments, the agent is a small molecule. In some embodiments, the agent is a small molecule that naturally occurs in human tissues.
  • the biodegradable polymeric core material comprises the agent. In some embodiments, the biodegradable polymeric core material binds to the agent to allow controlled release of the agent to the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) .
  • the nutrients comprise nucleotides, amino acids, peptides, carbohydrates (such as monosaccharides, oligosaccharides or polysaccharides) , lipids, or vitamins.
  • the extracellular matrix molecule comprises polysaccharide, glycosaminoglycan, glycoprotein, structural protein (such as collagen or elastin) , or adhesion protein (such as fibronectin or laminin) .
  • Agents that facilitate cell proliferation include, but are not limited to, insulin, insulin growth factor (IGF, such as IGF-I or IGF-II) , transforming growth factor (TGF, such as TGF ⁇ and TGF ⁇ ) , vascular epidermal growth factor (VEGF) , epidermal growth factor (EGF) , fibroblast growth factor (FGF) , platelet-derived growth factor (PDGF) , osteosarcoma source growth factor (ODGF) , somatostatin (SRIH) , nerve growth factor (NGF) , interleukin (IL, such as IL-1, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12) , erythropoietin (EPO) , colony stimulating factor (CSF) , cortisol, thyroid hormones (such as T3 or T4) , chemokines (such as CCL, CXC, TGF, TGF,
  • Agents (such as cell factors) that facilitate cell differentiation include, but are not limited to, Oct3/4, Sox2, Klf4, c-Myc, GATA4, TSP1, ⁇ -glycerophosphate, dexamethasone, vitamin C, insulin, IBMX, indomethacin, PDGF-BB, 5-azacytidine, and combinations thereof.
  • Agents (such as cell factors) that facilitate cell migration include, but are not limited to, cAMP, PIP 3 , SDF-1, N-cadherin, NF- ⁇ B, osteonectin, thromboxane A2, Ras, and combinations thereof.
  • Agents (such as cell factors) that facilitate cell metabolism include, but are not limited to, IGF-I, TRIP-Br2, DKK-1, sRANKL, OPG, TRACP-5b, ALP, SIRT1 (2-7) , PGC-1 ⁇ , PGC-1 ⁇ , IL-3, IL-4, IL6, TGF- ⁇ , PGE2, G-CSF, TNF ⁇ , and combinations thereof.
  • Agents (such as cell factors) that facilitate cell secretion include, but are not limited to, P600, P110, TCGFIII, BSF-2, glucagon, ⁇ -adrenergic agonist, arginine, Ca 2+ , acetyl choline (ACH) , somatostatin, and combinations thereof.
  • the pharmaceutically active agent regulates (such as facilitates) cell proliferation, differentiation, migration, secretion and/or metabolism.
  • the pharmaceutically active agent is selected from the group consisting of rhIL-2, rhIL-11, rhEPO, IFN- ⁇ , IFN- ⁇ , IFN- ⁇ , G-CSF, GM-CSF, rHuEPO, sTNF-R1, rhTNF- ⁇ , and combinations thereof.
  • the core may comprise any number of agents, such as at least about any of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more agents.
  • the core comprises about any of 1-3, 3-5, 1-5, 1-8, 1-10, 2-5, 5-10, or 10-20 agents.
  • the core comprises at least one (including at least about any of 1, 2, 3, 4, 5, 6, 7, 8, or more) agent from each of the groups described above of (1) agents that facilitate cell proliferation, (2) agents that facilitate differentiation, (3) agents that facilitate migration, (4) agents that facilitate metabolism, and (5) agents that facilitate secretion.
  • the core comprises at least one (including at least about any of 1, 2, 3, 4, 5, 10, 15, or 20) agent that regulates (such as facilitates) cell proliferation, differentiation, migration, metabolism, and/or secretion, selected from the group consisting of insulin, IGF-I, IGF-II, TGF ⁇ , TGF ⁇ , VEGF, PDGF, ODGF, SRIH, NGF, IL-1, IL-2, IL-3, IL-4, IL-5, IL6, IL-7, EPO, CSF, cortisol, T3, T4, Oct3/4, Sox2, Klf4, c-Myc, GATA4, TSP1, ⁇ -glycerophosphate, dexamethasone, vitamin C, insulin, IBMX, indomethacin, PDGF-BB, 5-azacytidine, cAMP, PIP 3 , SDF-1, N-cadherin, NF- ⁇ B, osteonectin, thromboxane A2, Ras, TRIP-Br
  • a suitable concentration of the agent in the core depends on the efficacy, stability, and function of the agent, and composition of the core and/or shell.
  • the agent is present in the bio-block at a concentration of about 0.01 ng/mL to about 100 mg/mL.
  • the core and/or the shell comprises at least one nutrient for the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) .
  • the biodegradable polymeric core material and/or the biodegradable polymeric shell material further comprises at least one nutrient for the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) .
  • the biodegradable polymers in the core and/or the shell bind to the at least one nutrient to allow controlled release of nutrients to the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) .
  • the degradation products of the biodegradable polymers in the core and/or the shell provide at least one nutrient for the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) .
  • Nutrients contemplated herein include, but are not limited to nucleotides, amino acids, peptides (including proteins) , nucleic acids (including DNA, RNA, and oligonucleotides) , carbohydrates (including mono-, oligo-, and poly-saccharides) , lipids, vitamins, salts, and oxygen.
  • the percentage of nutrients in the bio-block depends on the actual application of the bio-block. In some embodiments, the weight percentage of nutrients in the bio-block is at least about any of 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 95%.
  • the weight percentage of nutrients in the bio-block is about any of 0-5%, 5%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-95%, 95%-100%, 0-10%, 10%-50%, 5%-25%, 0-50%, 25%-75%, or 50%-100%.
  • the core and/or the shell comprises an extracellular matrix (ECM) molecule.
  • ECM extracellular matrix
  • the biodegradable polymeric core material or the biodegradable polymeric shell material comprises an ECM molecule.
  • the biodegradable polymeric core material binds to the ECM molecule to allow controlled release of the ECM molecule to the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) .
  • ECM molecules contemplated herein include, but are not limited to, polysaccharides, proteins, and glycoproteins, such as glycosaminoglycans, proteoglycan, structural proteins (e.g.
  • the degradation products of the biopolymers in the core and/or the shell provide at least one precursor of extracellular matrix (ECM) material for the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) .
  • ECM extracellular matrix
  • Precursors of ECM molecules contemplated herein include, but are not limited to amino acids, carbohydrates (including monosaccharides and polysaccharides) , and lipids.
  • the amount of ECM molecule in the bio-block depends on the actual application of the bio-block. In some embodiments, the weight percentage of ECM molecule in the bio-block is at least about any of 0.1%, 1%, 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, or 80%.
  • the shell is permeable to nutrients, such as nutrients provided to the bio-blocks in the media or to the biocompatible material surrounding the bio-blocks.
  • the nutrients are selected from the group consisting of water, oxygen, carbohydrates, lipids, proteins, amino acids, peptides, minerals, vitamins, cell factors, nucleic acids, and combinations thereof.
  • the biodegradable polymeric core and/or shell material has a plurality of microchannels that allow exchange of nutrients or waste materials between the interior and exterior of the bio-block.
  • the nutrients (such as amino acids, nucleotides, oxygen, carbohydrates, lipids, vitamins, inorganic salt and other small molecules) diffuse through the plurality of microchannels in the biodegradable polymeric shell material.
  • the shell comprises one or more micropores. In some embodiments, the shell comprises a plurality of microchannels and micropores.
  • the exemplary bio-block illustrated in FIG. 1A shows micropores in the shell. Unlike microchannels that are inherent structural components of certain biodegradable polymers, micropores are fabricated pores scattered in the shell according to the design and preparation process of the bio-block. Micropores may have a larger size than microchannels, and allow exchange of larger nutrients or macromolecules, such as proteins and nucleic acids. In some embodiments, the average diameter (or size) of the microchannels in the shell is at least about any of 10, 20, 50, 100, 150, 200, 250, 300, 350, 400, or 500 nm.
  • the average diameter (or size) of the microchannels in the shell is about any one of 10-20, 20-50, 50-100, 100-150, 150-200, 200-250, 250-300, 300-400, 400-500, 10-50, 50-100, 100-500, 10-100, or 10-500 nm. In some embodiments, the average diameter (or size) of the micropores in the shell is at least about any of 50, 75, 100, 200, 400, 600, 800, 1000, 1500, 2000, 4000, or 5000 nm.
  • the average diameter (or size) of the micropores in the shell is about any one of 50-100, 100-200, 200-400, 400-600, 600-1000, 1000-5000, 50-200, 50-500, or 50-5000 nm.
  • the shell is permeable to macromolecules of a molecular weight larger than about any of 100 kDa, 110 kDa, 120 kDa, 130 kDa, 150 kDa, 200 kDa, 250 kDa, 300 kDa, 500 kDa, 1 MDa, 2 MDa, 5 MDa or more.
  • the shell is permeable to macromolecules of a molecular weight of about any one of 100 kDa to 150 kDa, 110 kDa to 200 kDa, 200 kDa to 300 kDa, 300 kDa to 500 kDa, 500 kDa to 1 MDa, 100 kDa to 200 kDa, 100 kDa to 250 kDa, 100 kDa to 300 kDa, 100 kDa to 500 kDa, 100 kDa to 1 Mda, 100 kDa to 5 MDa, 150 kDa to 300 kDa, 200 kDa to 500 kDa, 200 kDa to 1 Mda, or 200 kDa to 5 MDa.
  • the shell is permeable to immune-related molecules. In some embodiments, the shell is permeable to cytokines. In some embodiments, the shell is permeable to chemokines. In some embodiments, the shell is permeable to immunoglobulin, such as IgG, IgM, IgA, IgD, IgE.
  • bio-blocks described herein can be present in a mixture, wherein the bio-block is allowed to contact, or to fuse with another bio-block in the mixture.
  • the bio-block is isolated, i.e. the bio-block is not in direct contact with another bio-block.
  • the isolated bio-block is provided in a container.
  • compositions such as bio-ink compositions, pharmaceutical compositions
  • compositions comprising a plurality of any of the bio-blocks described herein or a plurality of isolated bio-blocks. It is intended that any of the properties (such as composition, ratio, physical and chemical properties, etc. ) of the bio-block as described herein can be combined with any of the properties (such as carrier properties, etc. ) of the bio-ink composition as described herein, as if each and every combination is individually described.
  • a bio-ink composition comprising a plurality of bio-blocks each comprising: a) a core comprising a biodegradable polymeric core material and an endothelial cell; and b) a shell comprising a biodegradable polymeric shell material.
  • a bio-ink composition comprising a plurality of bio-blocks each comprising: a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and b) a shell comprising a biodegradable polymeric shell material.
  • a bio-ink composition comprising a plurality of bio-blocks each comprising: a) a core comprising a biodegradable polymeric core material, an endothelial cell; b) a second core comprising a second biodegradable polymeric core material, and a stem cell (such as MSC) ; and c) a shell comprising a biodegradable polymeric shell material.
  • the plurality of bio-blocks is of the same type. In some embodiments, the plurality of bio-blocks is of different types. In some embodiments, the bio-block has one or more (such as any of 1, 2, 3, 4, 5, or 6) of the following properties or characteristics: (1) the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) ; (2) the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) ; (3) the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) ; (4) the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa; (5) the biodegradable polymeric core material comprises type I collagen; and (6) the core comprises an agent (such as at least 3 different agents)
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-ink composition comprising a plurality of bio-blocks each comprising: a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and b) a shell comprising a biodegradable polymeric shell material, wherein the bio-ink composition comprises at least about 50%bio-blocks (w/w) .
  • the plurality of bio-blocks is of the same type. In some embodiments, the plurality of bio-blocks is of different types.
  • the bio-block has one or more (such as any of 1, 2, 3, 4, 5, or 6) of the following properties or characteristics: (1) the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) ; (2) the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) ; (3) the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) ; (4) the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa; (5) the biodegradable polymeric core material comprises type I collagen; and (6) the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutical
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-ink composition comprising a plurality of bio-blocks and a carrier (such as a liquid or a paste) , wherein the plurality of bio-blocks each comprises: a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and b) a shell comprising a biodegradable polymeric shell material.
  • the plurality of bio-blocks is of the same type. In some embodiments, the plurality of bio-blocks is of different types.
  • the bio-block has one or more (such as any of 1, 2, 3, 4, 5, or 6) of the following properties or characteristics: (1) the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) ; (2) the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) ; (3) the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) ; (4) the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa; (5) the biodegradable polymeric core material comprises type I collagen; and (6) the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutical
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-ink composition comprising a plurality of bio-blocks and a carrier (such as a liquid or a paste) , wherein the plurality of bio-blocks each comprises: a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and b) a shell comprising a biodegradable polymeric shell material, wherein the bio-ink composition comprises at least about 50%bio-blocks (w/w) .
  • the plurality of bio-blocks is of the same type. In some embodiments, the plurality of bio-blocks is of different types.
  • the bio-block has one or more (such as any of 1, 2, 3, 4, 5, or 6) of the following properties or characteristics: (1) the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) ; (2) the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) ; (3) the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) ; (4) the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa; (5) the biodegradable polymeric core material comprises type I collagen; and (6) the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutical
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-ink composition comprising a plurality of bio-blocks and a carrier (such as a liquid or a paste) , wherein the plurality of bio-blocks each comprises: a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and b) a shell comprising a biodegradable polymeric shell material, and wherein the plurality of bio-blocks are suspended homogenously within the carrier.
  • the plurality of bio-blocks is of the same type. In some embodiments, the plurality of bio-blocks is of different types.
  • the bio-block has one or more (such as any of 1, 2, 3, 4, 5, or 6) of the following properties or characteristics: (1) the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) ; (2) the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) ; (3) the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) ; (4) the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa; (5) the biodegradable polymeric core material comprises type I collagen; and (6) the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutical
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-ink composition comprising a plurality of bio-blocks and a carrier (such as a liquid or a paste) , wherein the plurality of bio-blocks each comprises: a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and b) a shell comprising a biodegradable polymeric shell material, wherein the plurality of bio-blocks are suspended homogenously within the carrier, and wherein the bio-ink composition comprises at least about 50%bio-blocks (w/w) .
  • the plurality of bio-blocks is of the same type.
  • the plurality of bio-blocks is of different types.
  • the bio-block has one or more (such as any of 1, 2, 3, 4, 5, or 6) of the following properties or characteristics: (1) the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) ; (2) the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) ; (3) the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) ; (4) the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa; (5) the biodegradable polymeric core material comprises type I collagen; and (6) the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation
  • a cell factor such
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-ink composition comprising a plurality of bio-blocks and a carrier (such as a liquid or a paste) , wherein the plurality of bio-blocks each comprises: a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and b) a shell comprising a biodegradable polymeric shell material, and wherein the carrier has a viscosity of about 1 Pa ⁇ s to about 1000 Pa ⁇ s.
  • the plurality of bio-blocks is of the same type. In some embodiments, the plurality of bio-blocks is of different types.
  • the bio-block has one or more (such as any of 1, 2, 3, 4, 5, or 6) of the following properties or characteristics: (1) the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) ; (2) the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) ; (3) the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) ; (4) the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa; (5) the biodegradable polymeric core material comprises type I collagen; and (6) the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutical
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-ink composition comprising a plurality of bio-blocks and a carrier (such as a liquid or a paste) , wherein the plurality of bio-blocks each comprises: a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and b) a shell comprising a biodegradable polymeric shell material, wherein the carrier has a viscosity of about 1 Pa ⁇ s to about 1000 Pa ⁇ s, and wherein the bio-ink composition comprises at least about 50%bio-blocks (w/w) .
  • the plurality of bio-blocks is of the same type.
  • the plurality of bio-blocks is of different types.
  • the bio-block has one or more (such as any of 1, 2, 3, 4, 5, or 6) of the following properties or characteristics: (1) the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) ; (2) the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) ; (3) the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) ; (4) the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa; (5) the biodegradable polymeric core material comprises type I collagen; and (6) the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation
  • a cell factor such
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-ink composition comprising a plurality of bio-blocks and a carrier (such as a liquid or a paste) , wherein the plurality of bio-blocks each comprises: a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and b) a shell comprising a biodegradable polymeric shell material, wherein the plurality of bio-blocks are suspended homogenously within the carrier, and wherein the carrier has a viscosity of about 1 Pa ⁇ s to about 1000 Pa ⁇ s.
  • the plurality of bio-blocks is of the same type.
  • the plurality of bio-blocks is of different types.
  • the bio-block has one or more (such as any of 1, 2, 3, 4, 5, or 6) of the following properties or characteristics: (1) the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) ; (2) the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) ; (3) the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) ; (4) the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa; (5) the biodegradable polymeric core material comprises type I collagen; and (6) the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation
  • a cell factor such
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a bio-ink composition comprising a plurality of bio-blocks and a carrier (such as a liquid or a paste) , wherein the plurality of bio-blocks each comprises: a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and b) a shell comprising a biodegradable polymeric shell material, wherein the plurality of bio-blocks are suspended homogenously within the carrier, wherein the carrier has a viscosity of about 1 Pa ⁇ s to about 1000 Pa ⁇ s, and wherein the bio-ink composition comprises at least about 50%bio-blocks (w/w) .
  • a carrier such as a liquid or a paste
  • the plurality of bio-blocks is of the same type. In some embodiments, the plurality of bio-blocks is of different types. In some embodiments, the bio-block has one or more (such as any of 1, 2, 3, 4, 5, or 6) of the following properties or characteristics: (1) the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) ; (2) the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) ; (3) the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) ; (4) the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa; (5) the biodegradable polymeric core material comprises type I collagen; and (6) the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • the bio-ink composition comprises a carrier.
  • the carrier including its degradation products, is typically non-toxic to cells.
  • the carrier is non-immunogenic.
  • the carrier is a biocompatible material.
  • the carrier is a bioadhesive material.
  • bioadhesive material refers to a biodegradable and biocompatible material that can serve to agglutinate.
  • Agglutinate refers to fusion or adhesion of cells, cell aggregates, multicellular aggregates, multicellular bodies, and/or multicellular layers. The terms, “agglutinate” , “fuse” , and “adhere” are used herein interchangeably.
  • Suitable bioadhesive materials include, but are not limited to, collagen, fibrin, chitosan, alginate, starch, hyaluronic acid, laminin, agarose, gelatin, glucan, elastin, methylcellulose, polyvinyl alcohol, polyamino acid (such as polylysine) , polyacrylic acid, polymethacrylic acid, acrylate copolymer (such as copolymer of acrylic acid and polymethacrylic acid) , and combinations thereof.
  • the biocompatible material comprises a protein or a carbohydrate that adheres to other bio-blocks.
  • the biocompatible material binds the bio-blocks within a multi-dimensional construct, an artificial tissue, or a tissue progenitor.
  • the carrier comprises a biodegradable polymer.
  • the degradation product of the biodegradable polymer provides at least one nutrient or ECM precursor to the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte, or smooth muscle cell) in the bio-blocks.
  • the carrier further comprises an ECM molecule or at least one nutrient.
  • the carrier comprises a naturally occurring polymer or a derivative thereof.
  • the carrier comprises a polymer selected from the group consisting of collagen, fibrin, chitosan, alginate, oxidized alginate, starch, hyaluronic acid, laminin, agarose, gelatin, glucan, and combinations thereof.
  • the carrier comprises alginate (such as sodium alginate) .
  • the carrier comprises oxidized alginate. Any of the alginates and oxidized alginates described in the section “oxidized alginate” can be used in the carrier. Suitable percentage of the alginate, oxidized alginate, or combination thereof in the carrier is at least about any of 0.1%, 0.5%, 1%, 1.25%, 1.5%, 2%, 3%, 4%, 5%, 7.5%, or 10%.
  • the percentage of the alginate, oxidized alginate, or combination thereof in the carrier is about any of 0.1%-0.5%, 0.5%-1%, 1%-1.25%, 1.25%-1.5%, 1.5%-2%, 2%-3%, 3%-4%, 4%-5%, 5%-7.5%, 7.5%-10%, 0.1%-1%, 1%-1.5%, 1%-2%, 0.5-2.5%, 1%-3%, 5-10%or 0.5%-5%.
  • the percentage of the alginate, oxidized alginate, or combination thereof in the carrier is no more than about 5% (including for example, no more than about any of 4%, 2.5%, 1.5%, or 1%) .
  • the carrier comprises gelatin.
  • the percentage of gelatin in the carrier is at least about any of 0.1%, 0.5%, 1%, 1.25%, 1.5%, 2%, 3%, 4%, 5%, 7.5%, or 10%.
  • the percentage of gelatin in the carrier is about any of 0.1%-0.5%, 0.5%-1%, 1%-1.25%, 1.25%-1.5%, 1.5%-2%, 2%-3%, 3%-4%, 4%-5%, 5%-7.5%, 7.5%-10%, 0.1%-1%, 1%-1.5%, 1%-2%, 0.5-2.5%, 1%-3%, 5-10%or 0.5%-5%.
  • the carrier comprises alginate (such as sodium alginate) and gelatin.
  • the weight ratio of the alginate to the gelatin in the carrier is at least about any of 10: 1, 9: 1, 8: 1, 7: 1, 6: 1, 5: 1, 4: 1, 3: 1, 2: 1, 1: 1, 1: 2, 1: 3, 1: 4, 1: 5, 1: 6, 1: 7, 1: 8, 1: 9, or 1: 10.
  • the weight ratio of the alginate to the gelatin in the carrier is about any of 10: 1 to about 9: 1, about 9: 1 to about 8: 1, about 8: 1 to about 7: 1, about 7: 1 to about 6: 1, about 6: 1 to about 5: 1, about 5: 1 to about 4: 1, about 4: 1 to about 3: 1, about 3: 1 to about 2: 1, about 2: 1 to about 1: 1, about 1: 1 to about 1: 2, about 1: 2 to about 1: 3, about 1: 3 to about 1: 4, about 1: 4 to about 1: 5, about 1: 5 to about 1: 6, about 1: 6 to about 1: 7, about 1: 7 to about 1: 8, about 1: 8 to about 1: 9, about 1: 9 to about 1: 10, about 10: 1 to about 5: 1, about 5: 1 to about 1: 1, about 1: 1 to about 1: 5, about 1: 5 to about 1: 10, about 2: 1 to about 1: 2, about 4: 1 to about 1: 4, or about 10: 1 to about 1: 10.
  • the carrier comprises a synthetic polymer.
  • the carrier comprises a polymer selected from the group consisting of polypohosphazene, polyacrylic acid, polymethacrylic acid, acrylate copolymer (such as copolymer of acrylic acid and polymethacrylic acid) , polylactic acid (PLA) , polyglycolic acid (PGA) , poly- (lactide-coglycolide acid) (PLGA) , polyorthoester (POE) , polycaprolactone (PCL) , polyhydroxyrate (PHB) , polyamino acid (such as polylysine) , degradable polyurethane, copolymers thereof, and combinations thereof.
  • the carrier comprises the same polymer at different concentration or same composition of polymers with different weight ratios as the shell and/or the core of the bio-blocks. In some embodiments, the carrier comprises a different polymer as the shell and/or the core of the bio-blocks. In some embodiments, the carrier further comprises water, inorganic salt, pH buffer, stabilizer, or preservatives.
  • the carrier degrades completely within no more than about 28 days. In some embodiments, the carrier degrades completely within no more than about any of 21 days, 14 days, 12 days, 10 days, 9 days, 8 days, 7 days, 6 days, 5 days, 4 days, 3 days, or 2 days. In some embodiments, the carrier degrades completely within about any of 2-5 days, 2-6 days, 2-8 days, 2-10 days, 2-12 days, 2-14 days, 14-21 days, 21-28 days, 7-14 days, 5-10 days, or 2-28 days.
  • the carrier in the bio-ink composition is a paste. In some embodiments, the carrier in the bio-ink composition is semi-solid (such as a hydrogel) . In some embodiments, the carrier in the bio-ink composition is a liquid. In some embodiments, the bio-ink composition is essentially free of liquid.
  • the carrier is viscous. In some embodiments, the carrier has a viscosity of at least about any of 0.01, 0.1, 0.5, 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 150, 200, 300, 400, 500, 600, 700, 800, 900, 1000 Pa ⁇ s.
  • the carrier has a viscosity of about any of 0.01-0.1, 0.1-0.5, 0.5-1, 1-5, 5-10, 10-20, 20-25, 25-30, 30-40, 40-50, 50-60, 60-70, 70-80, 80-90, 90-100, 100-200, 200-300, 300-400, 400-500, 500-600, 600-700, 700-800, 800-900, 900-1000, 0.01-1, 1-10, 25-50, 10-30, 30-50, 50-100, 30-160, 1-50, 1-100, 1-200, 25-200, 50-150, 100-500, 500-1000, 1-250, 250-750, 1-500, or 1-1000 Pa ⁇ s.
  • the carrier has a viscosity of about 1 Pa ⁇ s to about 1000 Pa ⁇ s. In some embodiments, the carrier has a viscosity of about 30 Pa ⁇ s to about 160 Pa ⁇ s.
  • the carrier or the bio-ink composition (with or without carrier) is extrudable. “Extrudable” refers to the state of a composition, which can be forced (such as under pressure) to pass through a nozzle or an orifice to form a structure.
  • the carrier or the bio-ink composition (with or without carrier) is suitable for jetting through an inkjet nozzle.
  • the carrier or the bio-ink composition (with or without carrier) is suitable for forming microdroplets or a stream by inkjet.
  • the carrier or the bio-ink composition (with or without carrier) is suitable for extrusion by a microextrusion dispensing system.
  • the bio-ink composition further comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutically active agent.
  • the agent is a protein.
  • the agent is a human protein.
  • the agent is a small molecule.
  • the agent is a small molecule that naturally occurs in human tissues.
  • the biodegradable polymeric core material comprises the agent.
  • the biodegradable polymeric core material binds to the agent to allow controlled release of the agent to the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte, or smooth muscle cell) .
  • the nutrients comprise nucleotides, amino acids, peptides, carbohydrates (such as monosaccharides, oligosaccharides or polysaccharides) , lipids, or vitamins.
  • the extracellular matrix molecule comprises polysaccharide, glycosaminoglycan, glycoprotein, structural protein (such as collagen or elastin) , or adhesion protein (such as fibronectin or laminin) .
  • Agents that facilitate cell proliferation include, but are not limited to, insulin, insulin growth factor (IGF, such as IGF-I or IGF-II) , transforming growth factor (TGF, such as TGF ⁇ and TGF ⁇ ) , vascular epidermal growth factor (VEGF) , epidermal growth factor (EGF) , fibroblast growth factor (FGF) , platelet-derived growth factor (PDGF) , osteosarcoma source growth factor (ODGF) , somatostatin (SRIH) , nerve growth factor (NGF) , interleukin (IL, such as IL-1, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12) , erythropoietin (EPO) , colony stimulating factor (CSF) , cortisol, thyroid hormones (such as T3 or T4) , chemokines (such as CCL, CXC, TGF, TGF,
  • Agents (such as cell factors) that facilitate cell differentiation include, but are not limited to, Oct3/4, Sox2, Klf4, c-Myc, GATA4, TSP1, ⁇ -glycerophosphate, dexamethasone, vitamin C, insulin, IBMX, indomethacin, PDGF-BB, 5-azacytidine, and combinations thereof.
  • Agents (such as cell factors) that facilitate cell migration include, but are not limited to, cAMP, PIP 3 , SDF-1, N-cadherin, NF- ⁇ B, osteonectin, thromboxane A2, Ras, and combinations thereof.
  • Agents (such as cell factors) that facilitate cell metabolism include, but are not limited to, IGF-I, TRIP-Br2, DKK-1, sRANKL, OPG, TRACP-5b, ALP, SIRT1 (2-7) , PGC-1 ⁇ , PGC-1 ⁇ , IL-3, IL-4, IL6, TGF- ⁇ , PGE2, G-CSF, TNF ⁇ , and combinations thereof.
  • Agents (such as cell factors) that facilitate cell secretion include, but are not limited to, P600, P110, TCGFIII, BSF-2, glucagon, ⁇ -adrenergic agonist, arginine, Ca 2+ , acetyl choline (ACH) , somatostatin, and combinations thereof.
  • the pharmaceutically active agent regulates (such as facilitates) cell proliferation, differentiation, migration, secretion and/or metabolism.
  • the pharmaceutically active agent is selected from the group consisting of rhIL-2, rhIL-11, rhEPO, IFN- ⁇ , IFN- ⁇ , IFN- ⁇ , G-CSF, GM-CSF, rHuEPO, sTNF-R1, rhTNF- ⁇ , and combinations thereof.
  • the bio-ink composition is used for bioprinting of a multi-dimensional construct, an artificial tissue or a tissue-progenitor. In some embodiments, the bio-ink composition is used with other biocompatible materials, inks or compositions in bioprinting. In some embodiments, the bio-ink composition is used for inkjet printing. In some embodiments, the bio-ink composition is used for microextrusion.
  • compositions and isolated bio-blocks
  • a pharmaceutical composition comprising one or more bio-blocks described herein and a pharmaceutically acceptable carrier.
  • the one or more bio-blocks further comprise a therapeutic agent, such as a therapeutic protein, or a targeting agent.
  • the pharmaceutical composition further comprises a pharmaceutically acceptable carrier, excipients, stabilizing agents, and/or other agents, which are known in the art, to provide favorable properties for administration of the pharmaceutical composition to a subject (such as a human subject) .
  • Suitable pharmaceutical carriers include sterile water; saline, dextrose; dextrose in water or saline; condensation products of castor oil and ethylene oxide combining about 30 to about 35 moles of ethylene oxide per mole of castor oil; liquid acid; lower alkanols; oils such as corn oil; peanut oil, sesame oil and the like, with emulsifiers such as mono-or di-glyceride of a fatty acid, or a phosphatide, e.g., lecithin, and the like; glycols; polyalkylene glycols; aqueous media in the presence of a suspending agent, for example, sodium carboxymethylcellulose; sodium alginate; poly (vinylpyrolidone) ; and the like, alone, or with suitable dispensing agents such as lecithin; polyoxyethylene stearate; and the like.
  • a suspending agent for example, sodium carboxymethylcellulose; sodium alginate; poly (vinylpyrolidone)
  • the carrier may also comprise adjuvants such as preserving stabilizing, wetting, emulsifying agents and the like together with the penetration enhancer.
  • adjuvants such as preserving stabilizing, wetting, emulsifying agents and the like together with the penetration enhancer.
  • the final form may be sterile and may also be able to pass readily through an injection device such as a hollow needle. The proper viscosity may be achieved and maintained by the proper choice of solvents or excipients.
  • compositions described herein may include other agents, excipients, or stabilizers to improve properties of the composition.
  • suitable excipients and diluents include, but are not limited to, lactose, dextrose, sucrose, sorbitol, mannitol, starches, gum acacia, calcium phosphate, alginates, tragacanth, gelatin, calcium silicate, microcrystalline cellulose, polyvinylpyrrolidone, cellulose, water, saline solution, syrup, methylcellulose, methyl-and propylhydroxybenzoates, talc, magnesium stearate and mineral oil.
  • the pharmaceutical composition is formulated to have a pH in the range of about 4.5 to about 9.0, including for example pH ranges of about any one of 5.0 to about 8.0, about 6.5 to about 7.5, or about 6.5 to about 7.0.
  • the pharmaceutical composition can also be made to be isotonic with blood by the addition of a suitable tonicity modifier, such as glycerol.
  • the pharmaceutical composition is used in cell therapy. In some embodiments, the pharmaceutical composition is used in regenerative medicine.
  • a plurality of isolated bio-blocks according to any one of the bio-blocks described above, and wherein the bio-blocks are isolated from each other.
  • each of the isolated bio-blocks in the plurality of the isolated bio-blocks is provided in a separate container.
  • the plurality of isolated bio-blocks is provided in a single container. Suitable container includes, but is not limited to, a dish (such as tissue culture or cell culture dish) , a flask, a vial, a tube (such a test tube, a microcentrifuge tube, a centrifuge tube etc.
  • the plurality of isolated bio-blocks is analyzed in parallel (e.g. simultaneously) , and/or in a high throughput screening context.
  • a container comprising a plurality of isolated bio-blocks according any of the bio-blocks described above.
  • the container further comprises a liquid or semi-liquid composition comprising agents, inorganic salt, culturing media, buffers, or other components useful for culturing or conducting experiments on the plurality of isolated bio-blocks.
  • the liquid or semi-liquid composition further comprises an agent or combination of agents that regulates (such as facilitates) cell activities, comprising cell proliferation, differentiation, migration, metabolism, secretion, or signaling.
  • the liquid or semi-liquid composition further comprises a compound (such as a surfactant) that helps to keep the bio-blocks isolated.
  • the liquid or semi-liquid composition further comprises stabilizer, or preservatives.
  • the plurality of isolated bio-blocks is dispensed in the liquid or semi-liquid composition.
  • each of the at least two isolated bio-blocks comprises a different agent or combination of agents that regulates (such as facilitates) cell proliferation, differentiation, migration, metabolism, secretion, or any combination thereof.
  • the plurality of isolated bio-blocks or the container is used for tissue engineering. In some embodiments, the plurality of isolated bio-blocks or the container is used as a research tool in in vitro research or in vivo research. In some embodiments, the plurality of isolated bio-blocks or the container is used to study cell signaling. In some embodiments, the plurality of isolated bio-blocks or the container is used to study stem cell differentiation.
  • the composition (such as the bio-ink composition or the pharmaceutical composition) consists of or consists essentially of the bio-blocks.
  • the composition (such as the bio-ink composition, or the pharmaceutical composition) or the plurality of isolated bio-blocks comprises at least about 50%of bio-blocks by weight.
  • the composition (such as the bio-ink composition or the pharmaceutical composition) or the plurality of isolated bio-blocks comprises at least about any of 10%, 20%, 30%, 40%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, or 99%of bio-blocks by weight.
  • the composition (such as the bio-ink composition or the pharmaceutical composition) or the plurality of isolated bio-blocks comprises about any of 10%-20%20%-30%, 30%-40%, 40%-50%, 50%-55%, 55%-60%, 60%-65%, 65%-70%, 70%-75%, 75%-80%, 80%-85%, 85%-90%, 90%-95%, 95%-100%, 10%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%, 50%-75%, 75%-100%, 10%-75%, or 50%-100%of bio-blocks by weight.
  • the composition (such as the bio-ink composition or the pharmaceutical composition) or the plurality of isolated bio-blocks is essentially free of liquid, such as having less than about any of 1%, 2.5%, 5%, 7.5%, or 10%of liquid except for the liquid contained in the bio-blocks.
  • the composition (such as the bio-ink composition or the pharmaceutical composition) or the plurality of isolated bio-blocks comprises a plurality of any of the bio-blocks as described in the previous section.
  • the plurality of bio-blocks is of the same type.
  • the plurality of bio-blocks is of different types.
  • the plurality of bio-blocks is of about any of 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 types.
  • bio-blocks may differ in the size and/or shape of the bio-blocks, number, type, and/or location of the endothelial cell, the stem cell and optionally the tissue-specific cell in the bio-blocks, compositions of the biodegradable polymeric core material, compositions of the biodegradable polymeric shell material, agent (s) that facilitate activities (such as proliferation, differentiation, migration, metabolism and/or secretion) of the cells and incorporated in the core of the bio-blocks, nutrients and/or ECM molecules incorporated in the bio-blocks, and/or any of the other parameters described in the previous section.
  • agent agents that facilitate activities (such as proliferation, differentiation, migration, metabolism and/or secretion) of the cells and incorporated in the core of the bio-blocks, nutrients and/or ECM molecules incorporated in the bio-blocks, and/or any of the other parameters described in the previous section.
  • the average size of the bio-blocks in the composition (such as the bio-ink composition or the pharmaceutical composition) or the plurality of isolated bio-blocks is at least about any of 10, 20, 30, 50, 100, 120, 150, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800, 900, 1000, 1500, or 2000 ⁇ m.
  • the average size of the bio-blocks in the composition (such as the bio-ink composition or the pharmaceutical composition) or the plurality of isolated bio-blocks is about any of 10-20, 20-30, 30-50, 50-100, 100-150, 150-200, 200-250, 250-300, 300-350, 350-400, 400-450, 450-500, 500-600, 600-700, 700-800, 800-900, 900-1000, 1000-1500, 1500-2000, 10-50, 20-100, 100-200, 200-400, 500-600, 600-800, 800-1000, 1000-2000, 10-100, 100-500, 100-800, 500-1000, 300-800, 30-50, 30-200, 30-500, 30-800, 30-1000, 30-2000, or 20-2000 ⁇ m.
  • the average size of the bio-blocks in the composition (such as the bio-ink composition or the pharmaceutical composition) or the plurality of isolated bio-blocks is about 30 ⁇ m to about 800 ⁇ m. In some embodiments, the average size of the bio-blocks in the composition (such as the bio-ink composition or the pharmaceutical composition) or the plurality of isolated bio-blocks is about 100 to about 500 ⁇ m. In some embodiments, the variation of the size of the same type of bio-blocks in the composition (such as the bio-ink composition or the pharmaceutical composition) or the plurality of isolated bio- blocks is less than about any of 1%, 5%, 10%, 15%, 20%, 25%, 30%, or 35%of the average size of the same type of bio-blocks.
  • the average length of the bio-blocks in the composition (such as the bio-ink composition or the pharmaceutical composition) or the plurality of isolated bio-blocks is at least about any of 10, 20, 30, 50, 100, 120, 150, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800, 900, 1000, 1500, or 2000 ⁇ m.
  • the average length of the bio-blocks in the composition (such as the bio-ink composition or the pharmaceutical composition) or the plurality of isolated bio-blocks is about any of 10-20, 20-30, 30-50, 50-100, 100-150, 150-200, 200-250, 250-300, 300-350, 350-400, 400-450, 450-500, 500-600, 600-700, 700-800, 800-900, 900-1000, 1000-1500, 1500-2000, 10-50, 20-100, 100-200, 200-400, 500-600, 600-800, 800-1000, 1000-2000, 10-100, 100-500, 100-800, 500-1000, 300-800, 30-50, 30-200, 30-500, 30-800, 30-1000, 30-2000, or 20-2000 ⁇ m.
  • the average length of the bio-blocks in the composition (such as the bio-ink composition or the pharmaceutical composition) or the plurality of isolated bio-blocks is about 30 ⁇ m to about 800 ⁇ m. In some embodiments, the average length of the bio-blocks in the composition (such as the bio-ink composition or the pharmaceutical composition) or the plurality of isolated bio-blocks is about 100 to about 500 ⁇ m.
  • the variation of the dimensions (such as length, width, and/or thickness) of the same type of bio-blocks in the composition (such as the bio-ink composition or the pharmaceutical composition) or the plurality of isolated bio-blocks is less than about any of 1%, 5%, 10%, 15%, 20%, 25%, 30%, or 35%of the average size of the same type of bio-blocks.
  • the average total number of cells in the bio-blocks of the composition (such as the bio-ink composition or the pharmaceutical composition) or the plurality of isolated bio-blocks is at least about any of 2, 5, 10, 20, 30, 40, 50, 100, 200, 300, 500, 1000, 2000, 3000, 4000, 5000, 10000, 20000, 30000, 40000, 50000, 100000, 200000, 500000, or 1000000 cells.
  • the average total number of cells in the bio-blocks of the composition is about any of 1-2, 2-4, 4-6, 6-8, 8-10, 10-15, 15-20, 20-25, 25-30, 30-40, 40-50, 50-60, 60-70, 70-80, 80-90, 90-100, 100-150, 150-200, 200-300, 300-400, 400-500, 500-1000, 1000-2000, 1-10, 2-10, 2-5, 5-10, 10-20, 20-30, 30-50, 2-25, 25-50, 2-50, 50-100, 100-200, 50-250, 250-500, 500-2000, 2-100, 2-500, 2-2000, 2000-3000, 3000-4000, 4000-5000, 5000-10000, 10000-20000, 20000-30000, 30000-40000, 40000-50000, 50000-100000, 2-5000, 100-5000, 100-1500, 100-1000, 500-5000, 500-10000, 1000-5000, 1
  • the average total number of cells in the bio-blocks of the composition (such as the bio-ink composition or the pharmaceutical composition) or the plurality of isolated bio-blocks is about 2 cells to about 1000000 cells. In some embodiments, the average total number of cells in the bio-blocks of the composition (such as the bio-ink composition or the pharmaceutical composition) or the plurality of isolated bio-blocks is at least 50 cells. In some embodiments, the average total number of cells in the bio-blocks of the composition (such as the bio-ink composition or the pharmaceutical composition) or the plurality of isolated bio-blocks is about 2 cell to about 5000 cells, including, for example, about 2 cells to about 50 cells, or about 100 cells to about 5000 cells.
  • the variation in the total number of cells per bio-block among the same type of bio-blocks in the composition (such as the bio-ink composition or the pharmaceutical composition) or the plurality of isolated bio-blocks is less than about any of 1%, 5%, 10%, 15%, 20%, 25%, 30%, or 35%of the average total number of cells among the same type of bio-blocks.
  • the composition (such as the bio-ink composition or the pharmaceutical composition) is prepared by mixing a plurality of bio-blocks.
  • the bio-ink composition is prepared by mixing a plurality of bio-blocks with a carrier.
  • the composition (such as the bio-ink composition or the pharmaceutical composition) or the plurality of isolated bio-blocks is prepared under sterile conditions.
  • the composition (such as the bio-ink composition or the pharmaceutical composition) or the plurality of isolated bio-blocks is prepared in a GMP workshop.
  • the composition (such as the bio-ink composition or the pharmaceutical composition) or the plurality of isolated bio-blocks is prepared immediately before use.
  • the composition (such as the bio-ink composition or the pharmaceutical composition) or the plurality of isolated bio-blocks can be stored under refrigerated conditions (such as about 4°C) for at least about any of 3 hours, 6 hours, 12 hours, 1 day, 2 days, or 3 days prior to use.
  • refrigerated conditions such as about 4°C
  • the present application further provides methods of preparing an artificial tissue or the tissue progenitor, comprising bioprinting any of the bio-ink compositions described herein to obtain a multi-dimensional construct having a pre-determined pattern. It is intended that any of the properties (such as composition, ratio, physical and chemical properties, etc. ) of the bio-ink composition as described herein can be combined with any of the properties (such as steps, conditions, etc. ) of the methods of preparing an artificial tissue or tissue progenitor as described herein, as if each and every combination is individually described.
  • a method of preparing an artificial tissue or tissue progenitor comprising bioprinting (such as inkjet or microextrusion) a bio-ink composition to obtain a multi-dimensional construct having a pre-determined pattern, wherein the bio-ink composition comprises a plurality of bio-blocks each comprising: a) a core comprising a biodegradable polymeric core material, and an endothelial cell; and b) a shell comprising a biodegradable polymeric shell material.
  • a method of preparing an artificial tissue or tissue progenitor comprising bioprinting (such as inkjet or microextrusion) a bio-ink composition to obtain a multi-dimensional construct having a pre-determined pattern, wherein the bio-ink composition comprises a plurality of bio-blocks each comprising: a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and b) a shell comprising a biodegradable polymeric shell material.
  • a method of preparing an artificial tissue or tissue progenitor comprising bioprinting (such as inkjet or microextrusion) a bio-ink composition to obtain a multi-dimensional construct having a pre-determined pattern, wherein the bio-ink composition comprises a plurality of bio-blocks each comprising: a) a core comprising a biodegradable polymeric core material, and an endothelial cell; b) a second core comprising a second biodegradable polymeric core material and a stem cell (such as MSC) ; and c) a shell comprising a biodegradable polymeric shell material.
  • bioprinting such as inkjet or microextrusion
  • any of the methods of preparing an artificial tissue or tissue progenitor described above may have one or more of the following properties: (1) the bio-ink composition is not bioprinted onto a scaffold; (2) the bioprinting is carried out by inkjet or microextrusion; (3) the method further comprises culturing the multidimensional construct in vitro under a condition that allows the endothelial cell, the stem cell, and/or optionally the tissue-specific cell in the plurality of bio-blocks to proliferate, differentiate, metabolize, migrate, secrete, or any combination thereof.
  • a method of preparing an artificial tissue or tissue progenitor comprising bioprinting (such as inkjet or microextrusion) a bio-ink composition to obtain a multi-dimensional construct having a pre-determined pattern, wherein the bio-ink composition comprises a plurality of bio-blocks each comprising: a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and b) a shell comprising a biodegradable polymeric shell material.
  • the length of the artificial tissue or tissue progenitor is at least about 100 ⁇ m (such as at least about any of 200 ⁇ m, 500 ⁇ m, 1 mm or more) .
  • the thickness of the artificial tissue or tissue progenitor is at least about 100 ⁇ m (such as at least about any of 200 ⁇ m, 500 ⁇ m, 1 mm or more) .
  • the bio-ink composition has one or more (such as any of 1, 2, 3, 4, or 5) of the following properties or characteristics: (1) the bio-ink composition comprises a carrier (such as a liquid or a paste) ; (2) the plurality of bio-blocks are suspended homogenously within the carrier; (3) the carrier has a viscosity of about 1 Pa ⁇ s to about 1000 Pa ⁇ s; (4) the bio-ink composition comprises at least about 50%bio-blocks (w/w) ; and (5) the plurality of bio-blocks is of different types.
  • a carrier such as a liquid or a paste
  • the bio-ink composition comprises at least about 50%bio-blocks (w/w) ; and (5) the plurality of bio-blocks is of different types.
  • the bio-block has one or more (such as any of 1, 2, 3, 4, 5, or 6) of the following properties or characteristics: (1) the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) ; (2) the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) ; (3) the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) ; (4) the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa; (5) the biodegradable polymeric core material comprises type I collagen; and (6) the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutical
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a method of preparing an artificial tissue or the tissue progenitor comprising bioprinting (such as inkjet or microextrusion) a bio-ink composition to obtain a multi-dimensional construct having a pre-determined pattern, wherein the bio-ink composition comprises a plurality of bio-blocks each comprising: a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and b) a shell comprising a biodegradable polymeric shell material; and wherein the bio-ink composition is not bioprinted onto a scaffold.
  • bioprinting such as inkjet or microextrusion
  • the length of the artificial tissue or tissue progenitor is at least about 100 ⁇ m (such as at least about any of 200 ⁇ m, 500 ⁇ m, 1 mm or more) .
  • the thickness of the artificial tissue or tissue progenitor is at least about 100 ⁇ m (such as at least about any of 200 ⁇ m, 500 ⁇ m, 1 mm or more) .
  • the bio-ink composition has one or more (such as any of 1, 2, 3, 4, or 5) of the following properties or characteristics: (1) the bio-ink composition comprises a carrier (such as a liquid or a paste) ; (2) the plurality of bio-blocks are suspended homogenously within the carrier; (3) the carrier has a viscosity of about 1 Pa ⁇ s to about 1000 Pa ⁇ s; (4) the bio-ink composition comprises at least about 50%bio-blocks (w/w) ; and (5) the plurality of bio-blocks is of different types.
  • a carrier such as a liquid or a paste
  • the bio-ink composition comprises at least about 50%bio-blocks (w/w) ; and (5) the plurality of bio-blocks is of different types.
  • the bio-block has one or more (such as any of 1, 2, 3, 4, 5, or 6) of the following properties or characteristics: (1) the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) ; (2) the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) ; (3) the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) ; (4) the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa; (5) the biodegradable polymeric core material comprises type I collagen; and (6) the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutical
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a method of preparing an artificial tissue or the tissue progenitor comprising bioprinting (such as inkjet or microextrusion) a bio-ink composition to obtain a multi-dimensional construct having a pre-determined pattern, and culturing the multi-dimensional construct in vitro under a condition that allows the endothelial cell, the stem cell, and/or optionally the tissue-specific cell in the plurality of bio-blocks to proliferate, differentiate, metabolize, migrate, secrete, or any combination thereof, wherein the bio-ink composition comprises a plurality of bio-blocks each comprising: a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and b) a shell comprising a biodegradable polymeric shell material.
  • bioprinting such as inkjet or microextrusion
  • the endothelial cell, the stem cell, and/or optionally the tissue-specific cell in the plurality of bio-blocks survive after the bioprinting.
  • the shell is at least partially degraded (such as at least about any of 20%, 50%, or 80%, or fully degraded) during the culturing.
  • the length of the artificial tissue or tissue progenitor is at least about 100 ⁇ m (such as at least about any of 200 ⁇ m, 500 ⁇ m, 1 mm or more) .
  • the thickness of the artificial tissue or tissue progenitor is at least about 100 ⁇ m (such as at least about any of 200 ⁇ m, 500 ⁇ m, 1 mm or more) .
  • the bio-ink composition has one or more (such as any of 1, 2, 3, 4, or 5) of the following properties or characteristics: (1) the bio-ink composition comprises a carrier (such as a liquid or a paste) ; (2) the plurality of bio-blocks are suspended homogenously within the carrier; (3) the carrier has a viscosity of about 1 Pa ⁇ s to about 1000 Pa ⁇ s; (4) the bio-ink composition comprises at least about 50%bio-blocks (w/w) ; and (5) the plurality of bio-blocks is of different types.
  • the bio-block has one or more (such as any of 1, 2, 3, 4, 5, or 6) of the following properties or characteristics: (1) the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) ; (2) the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) ; (3) the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) ; (4) the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa; (5) the biodegradable polymeric core material comprises type I collagen; and (6) the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutical
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio-block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • a method of preparing an artificial tissue or the tissue progenitor comprising bioprinting (such as inkjet or microextrusion) a bio-ink composition to obtain a multi-dimensional construct having a pre-determined pattern, and culturing the multi-dimensional construct in vitro under a condition that allows the endothelial cell, the stem cell, and/or optionally the tissue-specific cell in the plurality of bio-blocks to proliferate, differentiate, metabolize, migrate, secrete, or any combination thereof, wherein the bio-ink composition comprises a plurality of bio-blocks each comprising: a) a core comprising a biodegradable polymeric core material, an endothelial cell, and a stem cell (such as MSC) ; and b) a shell comprising a biodegradable polymeric shell material; and wherein the bio-ink composition is not bioprinted onto a scaffold.
  • bioprinting such as inkjet or microextrusion
  • the endothelial cell, the stem cell, and/or optionally the tissue-specific cell in the plurality of bio-blocks survive after the bioprinting.
  • the shell is at least partially degraded (such as at least about any of 20%, 50%, or 80%, or fully degraded) during the culturing.
  • the length of the artificial tissue or tissue progenitor is at least about 100 ⁇ m (such as at least about any of 200 ⁇ m, 500 ⁇ m, 1 mm or more) .
  • the thickness of the artificial tissue or tissue progenitor is at least about 100 ⁇ m (such as at least about any of 200 ⁇ m, 500 ⁇ m, 1 mm or more) .
  • the bio-ink composition has one or more (such as any of 1, 2, 3, 4, or 5) of the following properties or characteristics: (1) the bio-ink composition comprises a carrier (such as a liquid or a paste) ; (2) the plurality of bio-blocks are suspended homogenously within the carrier; (3) the carrier has a viscosity of about 1 Pa ⁇ s to about 1000 Pa ⁇ s; (4) the bio-ink composition comprises at least about 50%bio-blocks (w/w) ; and (5) the plurality of bio-blocks is of different types.
  • the bio-block has one or more (such as any of 1, 2, 3, 4, 5, or 6) of the following properties or characteristics: (1) the ratio between the number of the endothelial cell and the number of the stem cell is at least about 1: 20 (such as at least about any of 1: 15, 1: 10 or 1: 5) ; (2) the bio-block (such as the core) further comprises a tissue-specific cell (such as a hepatocyte, or a smooth muscle cell) ; (3) the biodegradable polymeric shell material comprises polylysine (such as at least about 1%) ; (4) the shell is permeable to a macromolecule having a molecular weight larger than about 110 kDa; (5) the biodegradable polymeric core material comprises type I collagen; and (6) the core comprises an agent (such as at least 3 different agents) selected from a nutrient, an extracellular matrix molecule, a cell factor (such as factor that facilitates cell proliferation, differentiation, migration, metabolism, and/or secretion) , and a pharmaceutical
  • the length of the bio-block is about 30 ⁇ m to about 2 mm. In some embodiments, the ratio between the length and the thickness of the bio-block is no more than about 50: 1 (such as no more than about any of 20: 1, 10: 1, 5: 1, or 2: 1) . In some embodiments, the shell has a thickness of about 0.1 ⁇ m to about 50 ⁇ m (such as about 1 ⁇ m to about 20 ⁇ m) . In some embodiments, the shell has a modulus of elasticity of about 0.01 MPa to about 100 MPa. In some embodiments, the shell comprises one or more micropores (such as with a size of more than about 50 nm) . In some embodiments, the bio- block has a hardness of about 0.01 GPa to about 0.4 GPa. In some embodiments, the bio-block comprises at least two shells and/or at least two cores.
  • the method uses a single bio-ink composition. In some embodiments, the method uses at least two (including at least about any of 2, 3, 4, 5, 6, 7, 8, 9, or 10) bio-ink compositions.
  • the different bio-ink compositions may comprise different carriers, different types of bio-blocks, and/or different ratios of the types of bio-blocks.
  • the bioprinting is continuous or essentially continuous. In some embodiments, the method comprises bioprinting sequentially a plurality of layers to obtain a multi-dimensional construct having a pre-determined pattern comprising the plurality of layers, wherein each layer is bioprinted with a bio-ink composition according to the pre-determined pattern of the layer.
  • the method comprises bioprinting sequentially a plurality of segments to obtain a multi-dimensional construct having a pre-determined pattern comprising the plurality of segments, wherein each segment is bioprinted with a bio-ink composition according to the pre-determined pattern of the segment.
  • the carrier of the bio-ink composition provides a biocompatible (optionally bioadhesive) material to bind the bio-blocks in the layer, segment, and/or multi-dimensional construct.
  • the method uses a bio-ink composition that is essentially free of liquid.
  • the method comprises bioprinting a liquid-free bio-ink composition onto a surface comprising a biocompatible (optionally bioadhesive) material to obtain a multi-dimensional construct having a pre-determined pattern.
  • the method comprises bioprinting a liquid-free bio-ink composition and bioprinting a biocompatible (optionally bioadhesive) material to obtain a multi-dimensional construct having a pre-determined pattern.
  • the method further comprises preparing a bio-ink composition from a plurality of bio-blocks and optionally a carrier. In some embodiments, the method further comprises bioprinting other biocompatible materials, inks or compositions.
  • the bioprinting can be carried out using any known methods in the art, including, but not limited to using bioprinters, and manual deposition methods (such as using a pipette) .
  • the bioprinting is carried out by a rapid prototyping method.
  • the rapid prototyping method uses a three-dimensional delivery device (such as bioprinter) to deposit the bio-blocks or bio-ink compositions on a biocompatible surface (such as hydrogel and/or porous membrane) in a three-dimensional, automated, computer-aided fashion.
  • the bio-printing is carried out by an engineered process.
  • engineered process refers to a process of depositing cells, cell solution, cell suspension, gel or slurry containing cells, cell concentrates, multicellular aggregates, and/or bio-blocks, etc., in a three dimensional structure according to a computer script using a computer-aided device.
  • the computer script is one or more computer programs, computer applications, or computer modules.
  • the bio-blocks fused after the bio-printing to form a three-dimensional construct.
  • Bioprinting using automated, computer-aided devices such as bioprinters
  • Advantages of methods using such devices include, for example, rapid, precise, and reproducible placement of the bio-blocks, and using a pre-determined plan and/or pattern to build the multidimensional construct having different types of cells, bio-blocks, and/or layers thereof.
  • bioprinters such as the bioprinters developed by Cyfuse, Organovo, EnvisionTEC, and Revotek can be used in the bioprinting process.
  • bioprinters There are currently three main types of bioprinters, including inkjet bioprinters, microextrusion bioprinters, and laser-assisted bioprinters, as described in Murph SV and Atala A. (2014) Nature Biotechnology, 32 (8) : 773-785, incorporated herein by reference.
  • the present invention contemplates use of any of the known bioprinters or bioprinters specially developed by the inventors in the method of preparing a tissue construct or the tissue progenitor using the bio-ink composition described herein.
  • the bioprinting is carried out by inkjet.
  • the ink-jet bioprinters are Drop-On-Demand inkjet bioprinters.
  • the ink-jet bioprinters are continuous ink-jet bioprinters.
  • the inkjet bioprinter is a thermal ink-jet bioprinter, which heats the printer head to produce air pressure to force the bio-ink out of the inkjet nozzle.
  • the nozzle heats up the bio-blocks in the bio-ink by at least about any of 0.1°C, 0.2 °C, 0.5 °C, 0.75 °C, 1 °C, 1.5 °C, 2 °C, or more.
  • the inkjet bioprinter is an acoustic bioprinter, which uses pulses formed by piezoelectric or ultrasound pressure to force the bio-ink out of the inkjet nozzle.
  • each droplet of the bio-ink forced out of the inkjet nozzle has a single bio-block.
  • each droplet of the bio-ink forced out of the inkjet nozzle comprises no more than about any of 2, 3, 4, 5, 10, 15, 20, 25, 50, 100, or more bio-blocks.
  • the bioprinting is carried out by microextrusion.
  • the bio-ink composition is extruded by a pneumatic dispensing system.
  • the bio-ink composition is extruded by a mechanical (such as piston or screw) dispensing system.
  • the pressure on the bio-ink composition during bio-printing is at least about any of 5 KPa, 10 KPa, 20 KPa, 40 KPa, 60 KPa, 80 KPa, 100 KPa, 120 KPa, 150 KPa, 200 KPa or more.
  • the speed of the bioprinting is about at least any of 50 mm/min, 100 mm/min, 150 mm/min, 200 mm/min, 250 mm/min, 300 mm/min, 400 mm/min, 500 mm/min or more.
  • the pressure and/or shearing force exerted by the bioprinter is not suitable for bioprinting cells suspended in the carrier (rather than as a bio-ink composition of the present application) .
  • the carrier for example, more than about any of 10%, 20%, 30%, 40%, 50%, or more the endothelial cell, the stem cell, and/or optionally the tissue-specific cell are damaged or killed when bioprinted as a suspension in the carrier (rather than as a bio-ink composition of the present application) using the bioprinters.
  • the methods described herein may use any of the low-temperature deposition technologies, or UV curing technologies known in the art to prepare the multi-dimensional construct using the bio-ink compositions.
  • Examples of inkjet bioprinting, low-temperature deposition, and UV curing technologies have been described, for example, in Malda, Jos, et al. "25th anniversary article: engineering hydrogels for biofabrication. " Advanced Materials 25.36 (2013) : 5011-5028, which is incorporated herein by reference in its entirety.
  • the bioprinting is carried out in a successive layer-by-layer fashion for an artificial tissue or tissue progenitor comprising multiple structural layers.
  • “Layer” as used in reference to a multi-layered, bioprinted tissue or construct refers to a planar structure having the thickness of a single building block (such as a bio-block) , wherein two or more of the planar structures can be stacked along the z-axis (i.e., the vertical axis) to achieve the total thickness of the bioprinted tissue or construct.
  • each of the layers in the tissue or construct have substantially the same structure and/or composition.
  • each of the layers in the tissue or construct have unique structures and/or compositions.
  • each layer i.e., the horizontal plane
  • a plurality of bio-blocks (or cells herein) and/or the void space therebetween are arranged according to a pre-determined spatial pattern.
  • the bio-blocks of the present application comprise one or more cells (such as at least about any of 10, 100, or 1000)
  • each layer in a multi-layered tissue or construct may have the thickness of one or more cells.
  • each layer has the thickness of a single cell.
  • each layer has the thickness of more than (such as at least about any of 10, 100, or 1000) one cells.
  • the method comprises bioprinting the bio-ink composition to deposit one layer at a time.
  • the method comprises bioprinting the bio-ink composition to deposit multiple (such as about any of 2, 3, 4, 5, 10 or more) layers at a time.
  • each layer comprises more than one (such as about any of 2, 3, 4, 5, 10 or more) cell types.
  • the bio-blocks are bioprinted according to the pre-determined pattern of the multi-dimensional construct, cells within each layer are distributed in a pre-determined pattern in the x-y plane (i.e. horizontal plane) , and/or in a pre-determined pattern along the z-axis (i.e. vertical axis) .
  • the multi-dimensional constructs can be of any pre-determined pattern, including any pre-determined shape.
  • the multi-dimensional construct may be a sheet (such as a rectangular, square, circular, elliptical, or hexagonal sheet, or a sheet of irregular shape) , a hollow tube, a hollow multi-dimensional construct (such as a hollow cube, a hollow sphere, a hollow rectangular prism, a hollow cylinder, or a hollow multi-dimensional construct of irregular shape) , or a solid multi-dimensional construct (such as a solid cube, a solid sphere, a solid rectangular prism, a solid cylinder, or a solid multi-dimensional construct of irregular shape) , or any combination thereof.
  • the multi-dimensional construct has a shape that mimics the natural shape of a tissue or an organ.
  • the bioprinting is continuous or substantially continuous.
  • continuous bioprinting is carried out as follows: dispense the bio-ink composition via a dispensing end (such as syringe, capillary tube, etc. ) that is connected to a reservoir containing the bio-ink composition.
  • the continuous bioprinting dispenses the bio-ink composition according to a repeating pattern of basic functional units in the multi-dimensional construct.
  • the repeating functional units may have any suitable geometric shapes, including, for example, circle, square, rectangle, triangle, polygon, and irregular shapes, in order to form one or more layers having a specific planar geometry to realize the unique deposition pattern of the bio-ink composition and/or void space.
  • the repeating functional unit has one layer, and consecutively bioprinting (such as depositing) multiple layers of the repeating functional units can provide a multi-layered artificial tissue or tissue progenitor having a specific geometric shape. In some embodiments, consecutively bioprinting (such as depositing) any of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or more layers provides the artificial tissue or tissue progenitor. In some embodiments, the artificial tissue or tissue progenitor having a shape in which the x-y plane of the shape is the planar geometric shape of the repeating functional unit.
  • the multi-dimensional construct can have any dimensions or sizes.
  • the multi-dimensional construct has a size of at least about any of 30 ⁇ m, 50 ⁇ m, 100 ⁇ m, 200 ⁇ m, 500 ⁇ m, 1 mm, 2 mm, 5 mm, 1 cm, 2 cm, 5 cm, 10 cm, 20 cm, or 50 cm.
  • the multi-dimensional construct has a length of at least about any of 30 ⁇ m, 50 ⁇ m, 100 ⁇ m, 200 ⁇ m, 500 ⁇ m, 1 mm, 2 mm, 5 mm, 1 cm, 2 cm, 5 cm, 10 cm, 20 cm, or 50 cm.
  • the multi-dimensional construct has a width of at least about any of 30 ⁇ m, 50 ⁇ m, 100 ⁇ m, 200 ⁇ m, 500 ⁇ m, 1 mm, 2 mm, 5 mm, 1 cm, 2 cm, 5 cm, 10 cm, 20 cm, or 50 cm. In some embodiments, the multi-dimensional construct has a thickness of at least about any of 30 ⁇ m, 50 ⁇ m, 100 ⁇ m, 200 ⁇ m, 500 ⁇ m, 1 mm, 2 mm, 5 mm, 1 cm, 2 cm, 5 cm, 10 cm, 20 cm, or 50 cm.
  • the multi-dimensional construct has a thickness comprising at least about any of 2, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, or more layers of the bio-blocks.
  • the ratio between the length and the width of the multi-dimensional construct is no more than about any of 10: 1, 9: 1, 8: 1, 7: 1, 6: 1, 5: 1, 4: 1, 3: 1, 2: 1, 1.5: 1, or 1: 1.
  • the ratio between the length and the width of the multi-dimensional construct is any of about 1: 1 to about 1.5: 1, about 1: 1 to about 2: 1, about 1: 1 to about 3: 1, about 1: 1 to about 4: 1, about 1: 1 to about 5: 1, about 1: 1 to about 6: 1, about 1: 1 to about 7: 1, about 1: 1 to about 8: 1, about 1: 1 to about 9: 1, or about 1: 1 to about 10: 1.
  • the ratio between the length and the thickness of the multi-dimensional construct is no more than about any of 100: 1, 90: 1, 80: 1, 70: 1, 60: 1, 50: 1, 40: 1, 30: 1, 20: 1, 10: 1, 9: 1, 8: 1, 7: 1, 6: 1, 5: 1, 4: 1, 3: 1, 2: 1, or 1: 1.
  • the ratio between the length and the thickness of the multi-dimensional construct is any of about 1: 1 to about 2: 1, about 1: 1 to about 3: 1, about 1: 1 to about 4: 1, about 1: 1 to about 5: 1, about 1: 1 to about 10: 1, about 1: 1 to about 20: 1, about to about 50: 1, or about 1: 1 to about 100: 1.
  • the method further comprises designing a model of the multi-dimensional construct according to the natural shape and/or cell distribution pattern of a tissue or an organ, wherein the tissue or the organ can be derived from the artificial tissue or the tissue progenitor being prepared.
  • the pre-determined pattern is defined by a scaffold.
  • the bio-ink composition is bioprinted onto a scaffold having a pre-determined pattern.
  • the scaffold is an artificial structure comprising biodegradable polymers, which is capable of supporting the bio-blocks in the bio-ink to form a multi-dimensional artificial tissue or tissue progenitor.
  • the method of preparing an artificial tissue or a tissue progenitor does not use a scaffold.
  • the method does not mechanically damage the endothelial cell, the stem cell, and/or optionally the tissue-specific cell in the bio-ink composition. In some embodiments, more than about any of 80%, 85%, 87.5%, 90%, 92.5%, 95%, or 98%of the endothelial cell, the stem cell, and/or optionally the tissue-specific cell in the bio-ink composition survives after the bioprinting. In some embodiments, more than about 90%of the endothelial cell, the stem cell, and/or optionally the tissue-specific cell in the bio-ink composition survives at least about any of 3 hours, 6 hours, 12 hours, 24 hours, 2 days, 4 days, or 1 week after the bioprinting.
  • more than about any of 80%, 85%, 87.5%, 90%, 92.5%, 95%, or 98%of the endothelial cell, the stem cell, and/or optionally the tissue-specific cell in the bio-ink composition is capable of proliferation after the bioprinting. In some embodiments, more than about any of 80%, 85%, 87.5%, 90%, 92.5%, 95%, or 98%of the endothelial cell, the stem cell, and/or optionally the tissue-specific cell in the bio-ink composition is capable of differentiation after the bioprinting.
  • more than about any of 80%, 85%, 87.5%, 90%, 92.5%, 95%, or 98%of the endothelial cell, the stem cell, and/or optionally the tissue-specific cell in the bio-ink composition have normal metabolism after the bioprinting. In some embodiments, more than about any of 80%, 85%, 87.5%, 90%, 92.5%, 95%, or 98%of the endothelial cell, the stem cell, and/or optionally the tissue-specific cell in the bio-ink composition is capable of migration after the bioprinting.
  • more than about any of 80%, 85%, 87.5%, 90%, 92.5%, 95%, or 98%of the endothelial cell, the stem cell, and/or optionally the tissue-specific cell in the bio-ink composition is capable of secretion after the bioprinting.
  • the bioprinting is carried out in vitro. In some embodiments, the bioprinting is carried out directly on a subject. In some embodiments, the subject is a human. In some embodiments, the bioprinting is carried out directly at a damaged site of a tissue of the subject. In some embodiments, the tissue of the subject is damaged by injury, an infection, a disease, or as a consequence of the aging process. In some embodiments, the tissue is a skin tissue. In some embodiments, the bioprinting directly at the damaged site of the tissue of the subject is according to the cell distribution information of the damaged site of the tissue or of the tissue.
  • the cell distribution information includes, but is not limited to, distinct layers of cells in the damaged site or the tissue, the type of cells of each layer, the ratio of different cells in each layer, the multi-dimensional distribution pattern of the cells in each layer, or any combination thereof.
  • the cell distribution information of the damaged site of the tissue is obtained prior to the bioprinting.
  • the endothelial cell, the stem cell, and/or optionally the tissue-specific cell in the bio-ink composition for bioprinting on the subject are derived from the subject.
  • the endothelial cell, the stem cell, and/or optionally the tissue-specific cell in the bio-ink composition for bioprinting on the subject are derived from a subject having similar characteristics (such as species, age, gender, disease, genetics information, etc. ) as the subject. In some embodiments, the endothelial cell, the stem cell, and/or optionally the tissue-specific cell in the bio-ink composition for bioprinting on the subject are derived from existing cell lines.
  • the method further comprises culturing the multi-dimensional construct under a condition that allows the endothelial cell, the stem cell, and/or optionally the tissue-specific cell within the bio-blocks to proliferate, differentiate, metabolize, migrate, and/or secrete.
  • the culturing condition depends on the type of cells, the types of bio-blocks used, the structure and design of the artificial tissue or tissue progenitor, and the physiology of the artificial tissue or tissue progenitor.
  • a person skilled in the art should be able to choose proper culturing conditions, such as media, pH, temperature, CO 2 levels, and duration. Typical tissue and cell culture conditions have been described in the art, for example, see Doyle, Alan, and J. Bryan Griffiths, eds.
  • the multi-dimensional construct is cultured for at least about any of 1 hour, 3 hours, 6 hours, 12 hours, 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, 8 days, 9 days, 10 days, 11 days, 12 days, 13 days, 14 days, 15 days, 16 days, 17 days, 18 days, 19 days, 20 days, 21 days, 25 days, or 30 days to obtain the artificial tissue or the tissue progenitor.
  • the multi-dimensional construct is cultured for about any of 1 hour to 3 hours, 3 hours to 6 hours, 6 hours to 12 hours, 12 hours to 1 day, 1 day to 3 days, 3 days to 5 days, 5 days to 7 days, 7 days to 10 days, 10 days to 14 days, 14 days to 21 days, 21 days to 28 days, 1 hour to 1 days, 1 day to 7 days, 7 days to 14 days, 1 days to 14 days, 14 days to 28 days, or 1 hour to 30 days to obtain the artificial tissue or the tissue progenitor.
  • the multi-dimensional construct is cultured in a 3D-culturing incubator.
  • the multi-dimensional construct is cultured in a bioreactor.
  • the multi-dimensional construct is cultured at about 37°C in about 5%CO 2 .
  • a physical stimulus such as stretching, shearing, light, heating or cooling, etc.
  • a chemical stimulus such as a hormone, a chemical gradient etc.
  • the biodegradable polymers in the bio-blocks (such as the biodegradable polymeric core material and/or the biodegradable polymeric shell material) , and/or the carrier, degrade during the culturing step to provide nutrients for the endothelial cell, the stem cell, and/or optionally the tissue-specific cell in the bio-blocks.
  • the biodegradable polymers in the bio-blocks (such as the biodegradable polymeric core material and/or the biodegradable polymeric shell material) , and/or the carrier, degrade during the culturing step to provide ECM molecules for the endothelial cell, the stem cell, and/or optionally the tissue-specific cell.
  • secretion from the endothelial cell, the stem cell, and/or optionally the tissue-specific cell during the culturing step integrates with the ECM in the multi-dimensional construct.
  • the endothelial cell, the stem cell, and/or optionally the tissue-specific cell in the bio-blocks connect to each other during the culturing step.
  • the endothelial cell, the stem cell, and/or optionally the tissue-specific cell from different bio-blocks connect to each other during the culturing step.
  • a high cell density (such as at least about any of 100, 200, 500, 1000, 2000, 5000, 10000, 20000, 50000, or 100000 cells/mm 3 ) is achieved in the multi-dimensional construct after the culturing step.
  • the endothelial cell, the stem cell, and/or optionally the tissue-specific cell proliferate to yield a more than about any of 2, 5, 10, 20, 50, 100, 200, 500, 1000, 2000, 5000, 10000, 20000, 50000, or 100000 fold increase in the cell number of the multi-dimensional construct during the culturing step.
  • an artificial tissue, a tissue progenitor, or a multi-dimensional construct prepared by any of the methods described in this section.
  • the artificial tissue, tissue progenitor or multi-dimensional construct has one or more blood capillaries.
  • the density of the blood capillaries in the artificial tissue, tissue progenitor, or multi-dimensional construct is about at least any of 1, 2, 5, 10, 20, 50, 100, or more per cm 3 .
  • Blood capillaries can be detected by immunohistochemical staining, such as using an anti-CD31 immunostain.
  • the artificial tissue, tissue progenitor or multi-dimensional construct has a microvascular network, i.e., the blood capillaries are connected to each other.
  • the artificial tissue, tissue progenitor or multi-dimensional construct is partially (such as at least about any of 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, or more) prepared by any of the methods described herein.
  • the artificial tissue, tissue progenitor, or multi-dimensional construct comprises a plurality of layers.
  • the artificial tissue forms by fusion of cells in the bio-blocks.
  • Artificial tissues contemplated herein include, but are not limited to, connective tissue (for example, loose connective tissue, dense connective tissue, elastic tissue, reticular connective tissue and adipose tissue) , muscle tissue (for example, skeletal muscle, smooth muscle and cardiac muscle) , urogenital tissue, gastrointestinal tissue, lung tissue, bone tissue, nerve tissue and epithelial tissue (for example, a single layer of epithelial and stratified epithelium) , endoderm-derived tissue, mesoderm-derived tissue and ectoderm-derived tissue, or any combination thereof.
  • the artificial tissue is a liver tissue.
  • the artificial tissue is a muscle tissue.
  • an artificial tissue, tissue progenitor, or multi-dimensional construct comprising or prepared using a plurality of any one of the bio-blocks provided herein.
  • an artificial liver tissue or progenitor thereof comprising or prepared using a plurality of bio-blocks each comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, a stem cell (such as MSC) , and a hepatocyte; and (b) a shell comprising a biodegradable polymeric shell material.
  • an artificial muscle tissue or progenitor thereof comprising or prepared using a plurality of bio-blocks each comprising: (a) a core comprising a biodegradable polymeric core material, an endothelial cell, a stem cell (such as MSC) , and a smooth muscle cell; and (b) a shell comprising a biodegradable polymeric shell material.
  • the bio-blocks are arranged in a pre-determined pattern.
  • the pre-determined pattern is based on the natural structure and cell distribution pattern of a tissue or an organ.
  • the plurality of bio-blocks comprises at least about any of 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 types of bio-blocks.
  • the plurality of bio-blocks comprises at least about any of 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 different cell types.
  • the artificial tissue, the tissue progenitor, or the multi-dimensional construct has a size of at least about any of 30 ⁇ m, 50 ⁇ m, 100 ⁇ m, 200 ⁇ m, 300 ⁇ m, 400 ⁇ m, 500 ⁇ m, 600 ⁇ m, 800 ⁇ m, 1 mm, 2 mm, 5 mm, 1 cm, 2 cm, 5 cm, 10 cm, 20 cm, or 50 cm.
  • the artificial tissue, the tissue progenitor, or the multi-dimensional construct has a size of any of about 1 ⁇ m to about 50 cm, about 100 ⁇ m to about 50 cm, about 10 ⁇ m to about 10 cm, about 50 ⁇ m to about 1 cm, about 100 ⁇ m to about 800 ⁇ m, or about 300 ⁇ m to about 600 ⁇ m.
  • the artificial tissue, the tissue progenitor, or the multi-dimensional construct has a length of at least about any of 1 ⁇ m, 10 ⁇ m, 30 ⁇ m, 50 ⁇ m, 100 ⁇ m, 200 ⁇ m, 300 ⁇ m, 400 ⁇ m, 500 ⁇ m, 600 ⁇ m, 800 ⁇ m, 1 mm, 2 mm, 5 mm, 1 cm, 2 cm, 5 cm, 10 cm, 20 cm, or 50 cm.
  • the artificial tissue, the tissue progenitor, or the multi-dimensional construct has a length of any of about 1 ⁇ m to about 50 cm, about 100 ⁇ m to about 50 cm, about 10 ⁇ m to about 10 cm, about 50 ⁇ m to about 1 cm, about 100 ⁇ m to about 800 ⁇ m, or about 300 ⁇ m to about 600 ⁇ m.
  • the artificial tissue, the tissue progenitor, or the multi-dimensional construct has a thickness of at least about any of 1 ⁇ m, 10 ⁇ m, 30 ⁇ m, 50 ⁇ m, 100 ⁇ m, 200 ⁇ m, 300 ⁇ m, 400 ⁇ m, 500 ⁇ m, 600 ⁇ m, 800 ⁇ m, 1 mm, 2 mm, 5 mm, 1 cm, 2 cm, 5 cm, 10 cm, 20 cm, or 50 cm.
  • the artificial tissue, the tissue progenitor, or the multi-dimensional construct has a thickness of any of about 1 ⁇ m to about 50 cm, about 100 ⁇ m to about 50 cm, about 10 ⁇ m to about 10 cm, about 50 ⁇ m to about 1 cm, about 100 ⁇ m to about 800 ⁇ m, or about 300 ⁇ m to about 600 ⁇ m. In some embodiments, the artificial tissue, the tissue progenitor, or the multi-dimensional construct has a thickness of at least about any of 2, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, or more layers of the bio-blocks.
  • the artificial tissue, the tissue progenitor, or the multi-dimensional construct has a thickness of about any of 1, 1-5, 5-10, 10-15, 15-20, 20-30, 30-40, 40-50, 50-100, 1-10, 1-20, 1-50, or 1-100 layers of the bio-blocks.
  • the artificial tissue, the tissue progenitor, or the multi-dimensional construct is further cultured to give rise to an organ or a functional unit of an organ, such as heart, liver, or kidney.
  • tissue progenitor prepared by any of the methods described herein. Accordingly, there is provided a method of preparing a tissue progenitor, comprising bioprinting a bio-ink composition to obtain a multi-dimensional construct having a pre-determined pattern, and optionally culturing the multi-dimensional construct under a condition that allows the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) to proliferate, differentiate, metabolize, and/or secrete.
  • the tissue progenitor is further cultured to give rise to a mini-tissue (i.e.
  • tissue progenitor is implanted in vivo to allow development into a tissue.
  • tissue progenitor is bioprinted directly in a subject to allow development of the tissue progenitor into a tissue.
  • the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) in the bio-block-based tissue progenitor described herein are not directly in contact with each other, especially cells in different bio-blocks, immediately after the bioprinting step. Culturing of the bioprinted multi-dimensional construct results in activities (such as proliferation, differentiation, migration, metabolism, secretion, etc.
  • the endothelial cell such as MSC
  • the tissue-specific cell such as hepatocyte or smooth muscle cell
  • the biodegradable polymeric materials of the bio-blocks for example, the biodegradable polymeric core material and/or the biodegradable polymeric shell material
  • precise cell distribution and regulation of cell activities can be achieved in a bio-block-based tissue progenitor, enabling production of more complicated tissues or organs, especially those with structural and cellular heterogeneity (such as cell type and/or composition) within the final tissue or organ product.
  • the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) in the different bio- blocks of the tissue progenitor proliferate, differentiate, migrate, or any combination thereof, and optionally the biodegradable polymeric core material is at least partially degraded.
  • the shell of the bio-blocks is completely degraded after culturing the multidimensional construct for about 2 days to about 28 days, such as any of about 2-3 days, about 3-4 days, about 4-7 days, or about 8-10 days.
  • the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) in the different bio-blocks of the tissue progenitor proliferate for more than about any of 1.5, 2, 5, 10, 20, 50, 100, 200, 500, 1000, 2000, 5000, 10000, 20000, 50000, or 100000 fold.
  • the proliferated cells penetrate the shell of the bio-blocks as the biodegradable polymeric core and/or shell material degrades.
  • the stem cell (such as MSC) differentiate to give rise to at least about any of 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 different cell types in the tissue progenitor.
  • the biodegradable polymeric core material is at least degraded for about any of 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90%.
  • the tissue progenitor, the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) in different bio-blocks are connected to each other, and wherein the biodegradable polymeric core material and/or the biodegradable polymeric shell material are at least partially degraded.
  • more than about any of 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90%of the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) in different bio-blocks are connected to each other.
  • the biodegradable polymeric shell material is at least degraded for about any of 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90%.
  • the carrier, or the biocompatible (optionally bioadhesive) material is at least degraded for about any of 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90%.
  • the degradation products of the biodegradable polymeric core material, the biodegradable polymeric shell material, the carrier, and/or the biocompatible (optionally bioadhesive) material provide nutrients and/or ECM molecules for the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) .
  • a method of preparing a mini-tissue, an artificial tissue, or an artificial organ comprising bioprinting a bio-ink composition to obtain a multi-dimensional construct having a pre-determined pattern, optionally culturing the multi- dimensional construct under a condition that allows the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) to proliferate, differentiate, metabolize, and/or secrete to obtain a tissue progenitor, and culturing the tissue progenitor under a condition that allows connection of the endothelial cell, the stem cell (such as MSC) , and/or optionally the tissue-specific cell (such as hepatocyte or smooth muscle cell) in different bio-blocks, and allows degradation of the biodegradable polymeric core material and biodegradable polymeric shell material to obtain the mini-tissue, the artificial tissue, or the artificial organ.
  • the tissue-specific cell such as hepatocyte or smooth
  • the tissue progenitor is cultured for at least about any of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 25, or 30 days to obtain the mini-tissue, the artificial tissue, or the artificial organ.
  • the tissue progenitor is cultured in a 3D-culturing incubator or bioreactor.
  • a physical and/or chemical stimulus is applied to the tissue progenitor during the culturing step.
  • One aspect of the present invention provides methods of preparing any of the bio-blocks as described above, including bio-blocks of various structures, such as bio-blocks with a single core and a single shell, bio-blocks having at least two cores, bio-blocks having at least two shells, and bio-blocks having at least two cores and at least two shells.
  • a method of preparing a bio-block comprising the steps of: (1) obtaining at least one core by each independently mixing a cell composition comprising an endothelial cell and optionally a stem cell (such as MSC) with a polymeric core material; and (2) coating the at least one core with at least one shell each independently comprising a polymeric shell material to obtain the bio-block.
  • step (1) further comprises granulation of the innermost core.
  • a method of preparing a bio-block comprising the steps of: (1) obtaining at least one core by each independently mixing a cell composition comprising an endothelial cell and optionally a stem cell (such as MSC) with a polymeric core material; (2) coating the at least one core with at least one shell each independently comprising a polymeric shell material; (3) coating the at least one shell with at least one additional core, wherein each of the at least one additional core independently comprises a polymeric core material and a cell composition; and (4) coating the at least one additional core with at least one additional shell each independently comprising a polymeric shell material to obtain the bio-block.
  • step (1) further comprises granulation of the innermost core.
  • a method of preparing a bio-block comprising the steps of: (1) obtaining at least one core by each independently mixing a cell composition comprising an endothelial cell and optionally a stem cell (such as MSC) with a polymeric core material; (2) coating the innermost core with at least one different core, wherein each of the at least one different core independently comprises a polymeric core material and a cell composition; and (3) coating the at least one different core with at least one shell each independently comprising a polymeric shell material to obtain the bio-block.
  • step (1) further comprises granulation of the innermost core.
  • a method of preparing a bio-block comprising the steps of: (1) obtaining at least one core by each independently mixing a cell composition comprising an endothelial cell and optionally a stem cell (such as MSC) with a polymeric core material; (2) coating the innermost core with at least one different core, wherein each of the at least one different core independently comprises a polymeric core material and a cell composition; (3) coating the at least one different core with at least one shell each independently comprising a polymeric shell material; (4) coating the at least one shell with at least one additional core, wherein each of the at least one additional core independently comprises a polymeric core material and a cell composition; and (5) coating the at least one additional core with at least one additional shell each independently comprising a polymeric shell material to obtain the bio-block.
  • the steps (4) and (5) are repeated for one or more times.
  • step (1) further comprises granulation of the innermost core.
  • a method of preparing a bio-block comprising the steps of: (1) mixing a cell composition comprising an endothelial cell and optionally a stem cell (such as MSC) with a polymeric core material to obtain a core; and (b) coating the core with a shell comprising a polymeric shell material to obtain the bio-block.
  • step (1) further comprises granulation of the core.
  • a method of preparing a bio-block comprising the steps of: (1) mixing a cell composition comprising an endothelial cell and optionally a stem cell (such as MSC) with a polymeric core material to obtain a core; (2) coating the core with a first shell comprising a first polymeric shell material; (3) coating the first shell with a second shell comprising a second polymeric shell material to obtain the bio-block.
  • step (1) further comprises granulation of the core.
  • a method of preparing a bio-block comprising the steps of: (1) mixing a first cell composition comprising an endothelial cell and optionally a stem cell (such as MSC) with a first polymeric core material to obtain a first core; (2) mixing a second cell composition with a second polymeric core material to obtain a second core; (3) coating the first core with the second core; (4) coating the second core with a shell comprising a polymeric shell material to obtain the bio-block.
  • step (1) further comprises granulation of the first core.
  • a method of preparing a bio-block comprising the steps of: (1) mixing a first cell composition comprising an endothelial cell and optionally a stem cell (such as MSC) with a first polymeric core material to obtain a first core; (2) mixing a second cell composition with a second polymeric core material to obtain a second core; (3) coating the first core with the second core; (4) coating the second core with a first shell comprising a first polymeric shell material; (5) coating the first shell with a second shell comprising a second polymeric shell material to obtain the bio-block.
  • step (1) further comprises granulation of the first core.
  • a method of preparing a bio-block comprising the steps of: (1) mixing a first cell composition comprising an endothelial cell and optionally a stem cell (such as MSC) with a first polymeric core material to obtain a first core; (2) coating the first core with a first shell comprising a first polymeric shell material; (3) mixing a second cell composition with a second polymeric core material to obtain a second core; (4) coating the first shell with the second core; (5) coating the second core with a second shell comprising a second polymeric shell material to obtain the bio-block.
  • step (1) further comprises granulation of the first core.
  • a method of preparing a bio-block comprising: (1) mixing an endothelial cell and optionally a stem cell (such as MSC) and a biodegradable core material to obtain a core material enwrapping the endothelial cell; and (2) granulating the core material, and coating the core material with a biodegradable shell material to obtain the bio-block.
  • step (1) further comprises mixing the endothelial cell and optionally the stem cell (such as MSC) , the biodegradable core material, and a suitable additional agent (such as a nutrient, ECM molecule, cell factor and/or pharmaceutically active agent) .
  • a device for preparing microspheroids or microcapsules such as an encapsulator is used for granulation and coating.
  • the method further comprises processing the shell of the bio-block (such as using a shell solidifying or crosslinking solution, for example, to improve the mechanical properties of the shell) after step (2) .
  • the method is carried out under sterile conditions.
  • the method is carried out in a GMP workshop.
  • the bio-block can be stored under refrigerated conditions (such as about 4°C) after preparation, for at least about any of 3 hours, 6 hours, 12 hours, 1 day, 2 days, or 3 days.
  • the polymeric core material and the polymeric shell material used in the methods described above may comprise any one or combinations of the materials suitable for use in bio-blocks as described in the “Bio-blocks” section, including naturally occurring polymers and synthetic polymers.
  • the cell composition may comprise any total number of cells (such as about 1 to about 1000000 cells) of any type or combination of types as described in the “Bio-blocks” sections.
  • Each core may comprise the same or different polymeric core material and/or the cell composition.
  • the cell composition further comprises the tissue-specific cell (such as hepatocyte or smooth muscle cell) .
  • Each shell may comprise the same or different polymeric shell material.
  • the polymeric core material of one or more (including all) cores is biodegradable.
  • the polymeric shell material of one or more (including all) shells is biodegradable.
  • the polymeric core material of all cores and the polymeric shell material of all shells are biodegradable.
  • step (1) comprises obtaining at least one core by each independently and mixing the cell composition, the polymeric core material and an additional agent comprising a nutrient, extracellular matrix, cell factor, or pharmaceutically active agent.
  • Any nutrient, extracellular matrix, cell factor, or pharmaceutically active agent as described in the “Bio-blocks” section may be used in the methods of preparing the bio-blocks.
  • any one or more (including all) of the shells (or the polymeric shell materials) may be further processed after the coating step (s) .
  • the outermost shell is processed.
  • only the outermost shell is processed.
  • Processing of the shell may comprise any steps known in the art to alter or improve the properties (such as chemical properties and/or mechanical properties) of the polymeric shell material.
  • the processing comprises solidifying the shell to improve mechanical properties (such as hardness and/or elasticity) of the shell.
  • the processing comprises treating the polymeric shell material with calcium (such as Ca 2+ ) to crosslink the alginate.
  • the coating and/or granulation steps may be carried out using any method and apparatus known in the art, such as using an encapsulator, a micropipette (e.g., using an extrusion method) , or a microinjection pump.
  • the coating and/or granulation steps are carried out on a hydrophobic surface.
  • the method is carried out under sterile conditions.
  • the method is carried out in a GMP workshop.
  • the method is carried out at about 4°C.
  • bio-blocks prepared any of the methods described herein may further be stored at appropriate conditions prior to use.
  • the bio-block can be stored under refrigerated conditions (such as about 4°C) for about 3 hours to about 3 days.
  • the bio-block can be stored under refrigerated conditions (such as about 4°C) for at least about any of 3 hours, 6 hours, 12 hours, 1 day, 2 days, or 3 days.
  • bio-block prepared by any one of the methods described herein.
  • bio-blocks Use of bio-blocks, pluralities of bio-blocks, compositions, tissue progenitors, and artificial tissues
  • bio-blocks any of the bio-blocks, the compositions (such as the bio-ink compositions or the pharmaceutical compositions) , the pluralities of isolated bio-blocks, the tissue progenitors, the artificial tissues, the artificial organs or the multi-dimensional constructs described in the present application may be useful for a variety of applications, such as tissue engineering, in vitro research, stem cell differentiation, in vivo research, drug screening, drug discovery, tissue regeneration, and regenerative medicine.
  • any of the bio-blocks, the multi-dimensional constructs, the tissue progenitors, or the artificial tissues described herein for stem cell differentiation research; drug discovery; drug screening; in vivo or in vitro assay; transplantation into a host; tissue engineering; tissue regeneration; analysis of cellular functions in response to a stimulus or an agent; study of in vivo effects of microenvironments; treating an individual in need thereof; evaluation of efficacy of a composition on a tissue or cells in a tissue; 3-dimensional tissue culture; or repair of a damaged tissue in an individual.
  • the bio-block is useful for tissue engineering.
  • the bio-block provides a unique microenvironment for the cell (s) inside the bio-block to allow study of culturing (such as three-dimensional culturing) conditions that allow cellular activities, including, but not limited to, proliferation, differentiation, metabolism, migration, secretion, signaling, tissue development and organogenesis.
  • tissue engineering is an interdisciplinary field that applies and combines the principles of engineering and life sciences.
  • tissue engineering refers to use of biological alternatives (such as the bio-blocks of the present application) to restore, maintain, or improve tissue functions.
  • the basic principle of classical tissue engineering involves obtaining a small amount of live tissue form an individual, isolating cells (also known as seed cells) from the live tissue using a special enzyme or other methods, culturing the isolated cells in vitro to proliferate the isolated cells, and mixing the proliferated cells with biocompatible, degradable, and absorbable biomaterials (i.e., scaffold) at a pre-determined ratio so that the cells adhere to the biomaterial (i.e., scaffold) to provide a cell-scaffold composition, and implanting the composition into a damaged site of a tissue or organ in the individual.
  • biocompatible, degradable, and absorbable biomaterials i.e., scaffold
  • the implanted cells continuously proliferate and secrete extracellular matrix molecules, and eventually form the corresponding tissue or organ, thereby achieving the purposes of tissue repair and reconstruction.
  • the bio-blocks of the present application have one or more of the following advantages: the types and numbers of the cells in the bio-blocks can be controlled; the dimensions of the bio-blocks can be controlled; the core and shell of the bio-blocks each (such as independently) comprise biodegradable materials; and the degradation rate of the shells of the bio-blocks can be controlled. Therefore, the bio-blocks of the present application are especially suitable for tissue engineering.
  • a method of providing a microenvironment comprising a plurality of microenvironmental factors to a cell comprising providing a bio-block comprising the cell and the plurality of microenvironmental factors, and culturing the bio-block under appropriate conditions.
  • Exemplary microenvironmental factors include, but are not limited to, physical factors (e.g., mechanical factors, temperature, humidity, osmotic pressure, etc. ) ; chemical factors (e.g., pH, ionic concentrations, etc. ) ; biological factors (e.g., cells, cytokines, etc. ) .
  • the microenvironmental factors may dynamically regulate one or more activities of the cell, including, but not limited to, proliferation, differentiation, migration, metabolism, and secretion.
  • the plurality of microenvironmental factors comprises growth factors for the cell to grow and to differentiate. In some embodiments, the plurality of microenvironmental factors comprises a structure and space for the cell to proliferate and to differentiate. In some embodiments, the plurality of microenvironmental factors comprises physical factors (such as mechanical stimuli) for the cell to carry out its biological functions. In some embodiments, the plurality of microenvironmental factors comprises feeder cells to facilitate or to regulate differentiation of the stem cell.
  • a method of three-dimensional tissue culturing comprising providing a bio-block comprising a cell or a plurality of bio-blocks to be cultured, agents, or other components useful for the tissue culturing, and culturing the bio-block under appropriate conditions.
  • the cell in the bio-block can give rise to the cells naturally found in a tissue.
  • the cell is a stem cell.
  • a plurality of isolated bio-blocks such as any of the pluralities of isolated bio-blocks described above, is used to investigate of three-dimensional tissue culturing conditions.
  • the plurality of isolated bio-blocks is analyzed in parallel (e.g.
  • the plurality of isolated bio-blocks in the plurality of isolated bio-blocks are different, allowing simultaneous investigation of at least two tissue culturing conditions.
  • the plurality of isolated bio-blocks is provided in a container. In some embodiments, any of the containers comprising a plurality of bio-blocks (such as isolated bio-blocks as described above) is used for the method of three-dimensional culturing.
  • the bio-block, the plurality of isolated bio-blocks, the multi-dimensional construct (such as the composite construct) , the tissue progenitor or the artificial tissue is useful for in vitro research, including a variety of in vitro assays.
  • the in vitro assay is a procedure for testing or measuring the presence or activity of a substance (e.g., a chemical, molecule, biochemical, drug, etc. ) in an organic or biologic sample (e.g., cell aggregate, tissue, organ, organism, etc. ) .
  • a substance e.g., a chemical, molecule, biochemical, drug, etc.
  • an organic or biologic sample e.g., cell aggregate, tissue, organ, organism, etc.
  • the in vitro assay is qualitative.
  • the in vitro assay is quantitative.
  • the quantitative in vitro assay measures the amount of a substance in a sample.
  • Exemplary in vitro assays contemplated by the present application include, but are not limited to, image-based assays, measurement of secreted proteins, expression of markers, and production of proteins.
  • the in vitro assay is used to detect or measure one or more of: molecular binding (including radioligand binding) , molecular uptake, activity (e.g., enzymatic activity and receptor activity, etc. ) , gene expression, protein expression, receptor agonism, receptor antagonism, cell signaling, apoptosis, chemosensitivity, transfection, cell migration, chemotaxis, cell viability, cell proliferation, safety, efficacy, metabolism, toxicity, and abuse liability.
  • the in vitro assay is an immunoassay, including competitive immunoassays or noncompetitive immunoassays.
  • the in vitro assay is an enzyme-linked immunosorbent assay (ELISA) .
  • ELISA enzyme-linked immunosorbent assay
  • the bio-block, the multi-dimensional construct, the artificial tissue or the tissue progenitor provides molecules, cells, groups of cells, or tissues that are measured or detected in the in vitro assays.
  • a method of analyzing cellular functions in response to a stimulus or an agent comprising exposing the cells in the bio-block according to any one of the bio-blocks described above to the stimulus or the agent, and assessing a change in the cellular functions in the bio-block.
  • the cellular functions contemplated herein include, but are not limited to cell activities, cell behaviors, subcellular organelle dynamics and activities, and functions and activities of molecules inside cells. Examples of cellular functions include, but are not limited to, proliferation, differentiation, metabolism, migration, secretion, signaling, apoptosis, necrosis, death, chemotaxis, localization of molecules, binding of molecules, and the like.
  • the stimulus or the agent is provided in the core of the bio-block.
  • the bio-block is an isolated bio-block.
  • the bio-block is provided in a container.
  • the stimulus or the agent is provided in the container.
  • any one of the pluralities of isolated bio-blocks or the containers as described above is used in the method of analyzing cellular functions.
  • the stimulus or agent is a drug.
  • the method is used for determining the efficacy of the drug.
  • the method is used for screening the drug.
  • the bio-block is useful for studying stem cell differentiation.
  • any one of the pluralities of isolated bio-blocks, or the containers comprising a plurality of isolated bio-blocks as described in the previous sections is used to study stem cell differentiation, wherein each of the isolated bio-blocks comprises at least one stem cell.
  • at least two of the isolated bio-blocks in the plurality of the isolated bio-blocks or the container are different, allowing simultaneous investigation of the effects of at least two different conditions on stem cell differentiation.
  • each of the at least two isolated bio-blocks comprises a different type of stem cell.
  • the isolated bio-blocks comprise the same type of stem cell.
  • each of the at least two isolated bio-blocks comprises a different agent or combination of agents that regulates (such as facilitates) cell proliferation, differentiation, migration, metabolism, secretion, signaling, or any combination thereof.
  • the plurality of isolated bio-blocks is analyzed in parallel (e.g. simultaneously) , and/or in a high throughput screening context.
  • the bio-block, the bio-ink composition, the multi-dimensional construct, the artificial tissue or the tissue progenitor is useful for in vivo research.
  • the bio-block, the multi-dimensional construct, the tissue progenitor or the artificial tissue is used as a xenograph in a subject.
  • a method of analyzing cellular functions in response to a stimulus or agent comprising exposing the cells in a bio-block, and assessing a change of the cellular functions in the bio-block, wherein the bio-block is positions inside a subject.
  • the multi-dimensional construct, the tissue progenitor, or the artificial tissue is used for in vivo transplant in a subject.
  • the bio-block or the bio-ink composition is bioprinted directly in a subject.
  • the bio-ink composition is bioprinted according to cellular distribution pattern of a tissue.
  • the bio-ink composition is bioprinted onto a scaffold in the subject.
  • the subject is an animal model.
  • the effects of the in vivo microenvironment of the bio-block are studied as the cells in the bio-block proliferate, differentiate migrate, metabolize, secrete, or develop in the subject.
  • the in vivo research is used to assess the in vivo effect of a compound (such as a drug) on the cells in the bio-block, the tissue progenitor or the artificial tissue.
  • the in vitro and/or in vivo research is useful to discover, develop, or study any molecule, cells, or biological structures and their mechanisms in any area including, but not limited to, molecular biology, cell biology, developmental biology, translational biology, medicinal biology, or tissue engineering.
  • Exemplary applications of the in vitro and in vivo research include, but are not limited to, development of multi-dimensional culturing systems, signaling pathways, stem cell induction and differentiation, embryogenesis and development, immunology, interactions between cells and materials, cell therapy, tissue regeneration, and regenerative medicine.
  • the bio-block, the plurality of isolated bio-blocks, the multi-dimensional construct, the tissue progenitor, or the artificial tissue is useful for drug screening or drug discovery.
  • a method of analyzing cellular functions in response to a drug comprising exposing the cells in the bio-block to the drug, and assessing a change in cellular functions (such as proliferation, survival, signaling, gene expression, detoxification, toxicity, etc. ) .
  • the method is used to determine the efficacy of the drug.
  • the method is used to screen for the drug.
  • the cells in the bio-block are derived from a subject in need of the drug.
  • a method of assessing the effect of a factor such as chemical reagent, for example, compound; or physical stimulus, for example, radiation or heating
  • a factor such as chemical reagent, for example, compound; or physical stimulus, for example, radiation or heating
  • a method of assessing the effect of a compound on a tissue comprising exposing the artificial tissue or the tissue progenitor to the factor, and evaluating activities of the cells in the artificial tissue, or the tissue progenitor in response to the compound.
  • the compound is a drug.
  • the method is used to determine the efficacy of the drug.
  • the method is used to screen for the drug.
  • the cells in the bio-block are derived from a subject in need of the drug.
  • the bio-block, the plurality of isolated bio-blocks, the multi-dimensional construct, the artificial tissue or the tissue progenitor is used to prepare an array, microarray or chip of cells, multicellular aggregates or tissues for drug screening or drug discovery.
  • an array, microarray, or chip of tissues is used as part of a kit for drug screening of drug discovery.
  • each bio-block, plurality of isolated bio-blocks, multi-dimensional construct, tissue progenitor or artificial tissue exists within a well of a biocompatible multi-well container, wherein the container is compatible with one or more automated drug screening procedures and/or devices.
  • automated drug screening procedures and/or devices include any suitable procedure or device that is computer or robot-assisted.
  • the bio-block, the plurality of isolated bio-blocks, the multi-dimensional construct, the tissue progenitor, the artificial tissue, or any of the methods described herein is useful for drug screening or drug discovery to research or develop drugs potentially useful in any therapeutic area.
  • suitable therapeutic areas include, by way of non-limiting examples, infectious disease, hematology, oncology, pediatrics, cardiology, central nervous system disease, neurology, gastroenterology, hepatology, urology, infertility, ophthalmology, nephrology, orthopedics, pain control, psychiatry, pulmonology, vaccines, wound healing, physiology, pharmacology, dermatology, gene therapy, toxicology, and immunology.
  • the bio-block is useful for tissue regeneration.
  • the pharmaceutical composition comprising the bio-block is useful for treating a subject in need of protecting, repairing, or replacing a tissue by administering an effective amount the pharmaceutical composition to the subject.
  • a method of protecting a tissue comprising administering to a subject in need thereof an effective amount of the pharmaceutical composition.
  • a method of repairing a damaged tissue comprising administering to a subject in need thereof an effective amount of the pharmaceutical composition.
  • a method of replacing a tissue (such as a defective or missing tissue) comprising administering to a subject in need thereof an effective amount of the pharmaceutical composition.
  • the tissue is a skin tissue.
  • a method of cell therapy comprising administering to a subject in need thereof an effective amount of the pharmaceutical composition.
  • the effective amount of the pharmaceutical composition to be administered depends on actual need.
  • the effective amount of the pharmaceutical composition is enough to improve the tissue condition (such as integrity, health, appearance, etc. ) by at least about any of 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90%.
  • the effective amount of the pharmaceutical composition is more than about any of 1, 5, 10, 20, 50, 100, 200, 500, or 1000 bio-blocks.
  • the pharmaceutical composition is administered topically. In some embodiments, the pharmaceutical composition is administered by surgical implantation. Other exemplary routes of administration include, but are not limited to, intravenous, intra-arterial, intraperitoneal, intrapulmonary, intravesicular, intramuscular, intra-tracheal, subcutaneous, intraocular, intrathecal, or transdermal. In some embodiments, the pharmaceutical composition is administered for a single time. In some embodiments, the pharmaceutical composition is administered for multiple times.
  • the pharmaceutical composition is administered at an interval of any of three times per day, two times per day, once per day, once per two days, once per three days, once per week, once per two weeks, once per three weeks, once per month, once per two months, once per three months, once per six months, or once per year.
  • the bio-block, the bio-ink composition, the multi-dimensional construct, the tissue progenitor, or the artificial tissue is useful for tissue regeneration.
  • the multi-dimensional construct, the tissue progenitor, or the artificial tissue is used for in vivo tissue or organ transplantation.
  • the bio-block, the bio-ink composition, the multi-dimensional construct, the artificial tissue or the tissue progenitor is used to replace a damaged, diseased, or failing tissue or organ in a subject.
  • the subject is a human subject.
  • a method of repairing a damaged site of a tissue in a subject comprising bioprinting a bio-ink composition directly at the damaged site of the tissue of the subject.
  • the bio-ink composition is bioprinted onto a scaffold placed at the damaged site of the tissue.
  • the tissue is a skin tissue.
  • the method further comprises obtaining cell distribution information of the damaged site of the tissue, wherein the bioprinting is carried out according to the cell distribution information.
  • the cells in the bio-ink composition for bioprinting on the subject are derived from a subject having similar characteristics (such as species, age, gender, disease, genetics information, etc. ) as the subject.
  • the cells in the bio-ink composition for bioprinting on the subject are derived from existing cell lines.
  • the bio-block, the plurality of isolated bio-blocks, the multi-dimensional construct, the tissue progenitor or the artificial tissue is used to isolate cells (including stem cells, progenitor cells, immune cells, or other cells) for use in cell therapy.
  • the bio-block, the multi-dimensional construct, the tissue progenitor, or the artificial tissue is used to provide, secrete, or isolate biologically active molecules (such as hormones, growth factors, cytokines, ligands, etc. ) to induce tissue regeneration in a subject receiving the bio-block, the multi-dimensional construct, the tissue progenitor, or the artificial tissue, or derived products thereof (such as biologically active molecules or cells) .
  • the bio-block, the pharmaceutical composition, the multi-dimensional construct, the tissue progenitor, or the artificial tissue is used as a coating (such as an anticoagulant coating) .
  • kits useful for bioprinting a multi-dimensional construct, an artificial tissue, or a tissue progenitor comprising a plurality of any of the bio-blocks described herein.
  • the kit comprises at least about any of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 types of bio-blocks.
  • kits further comprises a carrier that can be mixed with the plurality of bio-blocks for bioprinting.
  • the kit further comprises a biocompatible (optionally bioadhesive) material for binding the bio-blocks in bioprinting.
  • the kit further comprises a model that defines a pre-determined pattern for the bioprinting.
  • the model is based on the natural structure and cell distribution of the multi-dimensional biological structure, tissue, or tissue progenitor to be bioprinted.
  • kits useful for bioprinting a multi-dimensional construct, an artificial tissue, or a tissue progenitor comprising any of bio-ink compositions described herein.
  • the bio-ink composition comprises at least about any of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 types of bio-blocks.
  • the kit comprises at least about any of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 types of bio-ink compositions.
  • the kit further comprises a biocompatible (optionally bioadhesive) material for binding the bio-blocks in bioprinting.
  • the kit further comprises a model that defines a pre-determined pattern for the bioprinting.
  • the model is based on the natural structure and cell distribution of the multi-dimensional construct, artificial tissue, or tissue progenitor to be bioprinted.
  • kits for tissue engineering, in vitro research, or in vivo research comprising any of the pluralities of isolated bio-blocks or the containers comprising a plurality of isolated bio-blocks described herein.
  • a kit for analyzing cellular functions in response to a stimulus or an agent comprising any of the bio-blocks, the pluralities of isolated bio-blocks, or the containers comprising a plurality of isolated bio-blocks described herein.
  • a kit for drug screening or drug discovery comprising a plurality of any of the bio-blocks, the bio-ink compositions, the pluralities of isolated bio-blocks, the tissue progenitors or the artificial tissues as describe herein.
  • a kit useful for treating a subject in need thereof comprising any of the pharmaceutical compositions, the bio-ink compositions, the tissue progenitors, or the artificial tissues as described herein.
  • kits may comprise additional components, such as containers, reagents, culturing media, buffers and the like that are necessary in the any one of the methods of bioprinting, treatment, or use described herein.
  • the kit further comprises a scaffold, or a material for preparing a scaffold.
  • the kit further comprises an instructional manual, such as a manual describing a protocol for preparing the multi-dimensional construct, the artificial tissue, or the tissue progenitor according to any of the methods described herein, including, for example, parameters for the bioprinting and culturing conditions.
  • the instructional manual describes a protocol, dosage, indications, administration schedule, etc. of the pharmaceutical composition.
  • kits may comprise a unit package of bio-blocks, bio-ink compositions, pluralities of isolated bio-blocks, and pharmaceutical compositions, bulk packages (e.g. multi-unit packages) or sub-unit packages.
  • the kits comprise sufficient bio-blocks or bio-ink compositions to prepare at least about any of 1, 2, 3, 4, 5, 10, 20, 50, 100 or more artificial tissues, tissue progenitors or multi-dimensional constructs.
  • the kits comprise sufficient pluralities of isolated bio-blocks or containers comprising a plurality of isolated bio-blocks to carry out at least about any of 1, 2, 3, 4, 5, 10, 20, 50, 100 or more in vitro, in vivo, stem cell differentiation, tissue engineering, tissue regeneration, drug screening or drug discovery experiments.
  • the kits may also include multiple units of bio-blocks, bio-ink compositions, pluralities of isolated bio-blocks, or pharmaceutical compositions, and instructions for use, and packaged in quantities sufficient for storage and use in a research laboratory or in pharmacies, such as hospital pharmacies.
  • kits comprising a multi-dimensional construct, a tissue progenitor, or an artificial tissue prepared by any of the methods of bioprinting using bio-blocks or bio-ink compositions as described herein.
  • the kit further comprises agents, culturing media, buffers, or other components useful for culturing the multi-dimensional construct, the tissue progenitor, or the artificial tissue to obtain a tissue or an organ.
  • the kit further comprises an instructional manual describing the culturing conditions.
  • the kit is useful for regenerative medicine, such as in vivo transplantation or cell therapy.
  • the kit is useful for in vitro assays.
  • the kit is useful for drug screening or drug discovery.
  • the multi-dimensional construct, the tissue progenitor, or the artificial tissue is placed in multi-well containers (such as a multi-well plate) for a drug screening assay or a drug discovery assay, for example a high throughput assay assisted by a computer or a robot.
  • the kit comprises reagents, or instructions that are useful for the assays or medical procedures (such as in vivo transplantation or cell therapy) .
  • kits of the invention are in suitable packaging.
  • suitable packaging include, but is not limited to, vials, bottles, jars, flexible packaging (e.g., Mylar or plastic bags) , and the like. Kits may optionally provide additional components such as buffers and interpretative information.
  • the present application thus also provides articles of manufacture, which include vials (such as sealed vials) , bottles, jars, flexible packaging, and the like.
  • “Commercial batch” used herein refers to a batch size that is at least about 100 bio-blocks. In some embodiments, the batch size is at least about any of 100, 200, 500, 1000, 2000, 5000, 10000, 20000, or 50000 bio-blocks.
  • the commercial batch comprises a plurality of vials comprising any of the compositions (such as the bio-blocks, the bio-ink compositions, or the tissue progenitor) .
  • the commercial batch comprises at least about any of 5, 10, 15, 20, 25, 50, 75, 100, 200, 300, 400, 500, 1000, 2000, 5000, or 10000 vials.
  • each vial comprises at least about any of 1, 2, 5, 10, or 100 bio-blocks.
  • Bio-blocks were prepared under sterile conditions. If the bio-blocks are used in human, then such bio-blocks should be prepared in a workshop having a biosafety level of GMP.
  • An encapsulator (BUCHI TM Encapsulator B-395 Pro) was used to prepare a batch of bio-blocks.
  • the concentric nozzles had the following diameters: inner nozzle: 200 ⁇ m; outer nozzle: 300 ⁇ m.
  • a microinjection pump may be used in place of the Encapsulator.
  • each bio-block had 100 Human Umbilical Vein Endothelial cells (HUVECs) and a size of about 600 ⁇ m.
  • This method can be used to prepare bio-blocks comprising MSCs, endothelial cells, and optionally tissue-specific cells (such as hepatocytes or smooth muscle cells) .
  • Type I collagen 4 mg/mL, neutralized with a sterile 1M sodium hydroxide (NaOH) solution
  • Sodium alginate (b) 2.5 % (w/v) Sodium alginate: The sodium alginate was prepared by dissolving sodium alginate in sterile deionized water. In a second batch of bio-blocks, 2%sodium alginate solution was used.
  • a 1: 1 (by weight) mixture of the type I collagen solution and the sodium alginate solution was prepared to prepare the core.
  • Solidifying (i.e., crosslinking) solution comprising an aqueous solution of 0.1 M calcium chloride (CaCl 2 ) .
  • bio-blocks were prepared as described in the following steps, which were all carried out on ice.
  • the core mixture and the shell mixture were each separately loaded into two 5 mL syringes. According to the manufacturer’s instructions, pressure, centrifugal force, and pump speed of the encapsulator were set, and the core mixture and the shell mixture were used for granulation and coating. A concentric nozzle set with an inner nozzle having a size of 200 ⁇ m and an outer nozzle having a size of 300 ⁇ m was used. The prepared bio-block microdroplets were collected in the beaker containing 300 mL 0.1 M CaCl 2 solution and crosslinked for about 5 minutes to obtain the bio-blocks.
  • the bio-blocks can be stored at 4°C, or directly used in 3D bioprinting.
  • This example analyzes characteristics of bio-blocks prepared using the method described in Example 1, including sizes of the bio-blocks, thickness of the shell, mechanical protection provided by the shell, and the number of cells in the bio-block.
  • Bio-blocks with different sizes were prepared using the method described in Example 1, wherein the sizes of the inner and outer nozzles of the concentric nozzle set were altered according to the final bio-block size in each preparation.
  • the bio-blocks were examined under a microscopy, and the results are shown in FIGs. 2A-2C.
  • the diameter of the bio-block in FIG. 2A is about 120 ⁇ m (scale is 100 ⁇ m) ;
  • the diameter of the bio-block in FIG. 2B is about 200 ⁇ m (scale is 100 ⁇ m) ;
  • the diameter of the bio-block in FIG. 2C is about 450 ⁇ m (scale is 200 ⁇ m) .
  • the thickness of the shell of the bio-blocks prepared in Example 1 was further examined under a microscope, and the results are shown in FIG. 3A, in which the highlighted part represented the shell of a bio-block.
  • the thickness of the shell of the bio-block is about 2 ⁇ m (scale is 50 ⁇ m) .
  • the results demonstrate that the thickness of the shell can be controlled by adjusting the parameters of the encapsulator, such as the diameters of the inner nozzle and the outer nozzle of the concentric nozzle set, and the pumping speed of the shell material.
  • the thickness of the shell of the bio-blocks of the present application is controllable, and can be selected based on needs.
  • Bio-blocks comprising different number of cells were also prepared using similar steps as in Example 1, wherein the cell density of the cell suspension used to make the core mixture was altered according to the target number of cells per bio-block in each preparation.
  • the bio-blocks were examined under a microscope and the results are shown in FIG. 2D-2F.
  • the bio-blocks in FIG. 2D each contained about 50 cells (scale is 100 ⁇ m) ;
  • the bio-blocks in FIG. 2E each contained about 8 cells (scale is 100 ⁇ m) ;
  • the bio-blocks in FIG. 2F each contained about 2 cells (scale is 100 ⁇ m) .
  • a nanoindenter (Hysitron TI 950, Minneapolis, MN, USA) was used according to the manufacturer’s instructions to measure the mechanical properties of the bio-blocks prepared using the method of Example 1 (size of the bio-blocks was about 400 ⁇ m) .
  • Three independent batches of bio-blocks were examined, and measurement was carried out at five different sampling locations within each batch.
  • the bio-blocks had a hardness of about 0.141 GPa to about 0.218 GPa, with an average hardness of 0.186 GPa.
  • the bio-blocks had a modulus of elasticity of about 2.942 MPa to about 3.562 MPa, with an average modulus of elasticity of about 3.278 MPa.
  • the average hardness of the bio-blocks was about 0.083 GPa, and the average modulus of elasticity was about 1.683 MPa.
  • bio-blocks had excellent mechanical protection capabilities, which can effectively avoid physical injury or mechanical damage from external forces to the cells inside the bio-blocks. Additionally, it was discovered that the mechanical protection capabilities of the bio-blocks can be controlled by adjusting parameters, such as thickness of the shell and the polymeric shell material of the bio-blocks (data not shown) . The mechanical protection capabilities of the bio-blocks are controllable, and can be selected based on needs. Bio-blocks comprising MSCs, endothelial cells, and optionally tissue-specific cells (such as hepatocytes or smooth muscle cells) may have similar properties as those described in this example.
  • bio-blocks (B1-B4 in Table 1 below) were prepared using an encapsulator with the method described in Example 1.
  • FIGs. 4A-4D show images of bio-blocks B1-B4 under a microscope.
  • the biodegradable polymeric core material of the bio-block B2 was stained using tracker CM-Dil (red fluorescence) , and FITC (green fluorescence) conjugated polylysine was used as the biodegradable polymeric shell material. Confocal microscopy was used to examine the bio-blocks B2 prepared using the biodegradable polymeric core and shell materials each with fluorescent labels. As shown in FIG. 4E, green fluorescence represents the shell of B2, and red fluorescence represents the core of B2.
  • This example provides a method of preparing exemplary bio-blocks comprising a shell that contains oxidized alginate.
  • Bio-blocks were prepared under sterile conditions. If the bio-blocks are used in human, then such bio-blocks should be prepared in a workshop having a biosafety level of GMP.
  • An encapsulator (BUCHI TM Encapsulator B-395 Pro) was used to prepare a batch of bio-blocks.
  • the concentric nozzles had the following diameters: inner nozzle: 200 ⁇ m; outer nozzle: 300 ⁇ m.
  • a microinjection pump may be used in place of the Encapsulator.
  • Type I collagen 4 mg/mL, neutralized with a sterile 1M sodium hydroxide (NaOH) solution
  • the solidifying (i.e., crosslinking) solution comprises a solution of 0.1 M calcium chloride (CaCl 2 ) .
  • HAVEC Human Umbilical Vein Endothelial cells
  • HepG2 hepatocellular carcinoma cells
  • human fibroblasts purchased from ATCC
  • MSC mouse mesenchymal stem cells
  • bio-blocks were prepared as described in the following steps, which were all carried out on ice.
  • the core mixture was placed in a 2 mL syringe. 50 mL polymeric shell material was placed in the enwrapping solution bottle of the encapsulator. The core mix and the polymeric shell material were then used for granulation and coating.
  • step (4) The product of step (4) was collected in a beaker containing 300 mL 0.1 M CaCl 2 solution, and crosslinked for 5 minutes to obtain the bio-blocks.
  • the bio-blocks can be stored at 4°C, or directly used in 3D bioprinting.
  • Example 5 Characterization of bio-blocks comprising shells comprising oxidized alginate.
  • This example analyzes characteristics of bio-blocks prepared using the method described in Example 4, including sizes of the bio-blocks, thickness of the shell, mechanical protection provided by the shell, and the number of cells in the bio-block.
  • Bio-blocks with different sizes were prepared the method described in Example 4, wherein the sizes of the inner and outer nozzles of the concentric nozzle set were altered according to the final bio-block size in each preparation.
  • the thickness of the shell of the bio-blocks prepared in Example 4 was further examined under a microscope. The results demonstrate that the thickness of the shell can be controlled by adjusting the parameters of the encapsulator, such as the diameters of the inner nozzle and the outer nozzle of the concentric nozzle set, and the pumping speed of the shell material.
  • the thickness of the shell of the bio-blocks is controllable, and can be selected based on needs.
  • Bio-blocks comprising different number of cells were also prepared using similar steps as in Example 4, wherein the cell density of the cell suspension used to make the core mixture was altered according to the target number of cells per bio-block in each preparation.
  • the results demonstrate that the number of cells contained in the bio-blocks can be controlled by adjusting the cell density of the cell suspension.
  • the number of cells contained in the bio-blocks is controllable, and can be selected based on needs.
  • bio-blocks of the present application had excellent mechanical protection capabilities, which can effectively avoid physical injury or mechanical damage from external forces to the cells inside the bio-blocks. Additionally, it was discovered that the mechanical protection capabilities of the bio-blocks can be controlled by adjusting parameters, such as thickness of the shell and the polymeric shell material of the bio-blocks (data not shown) . The mechanical protection capabilities of the bio-blocks are controllable, and can be selected based on needs.
  • the degradation rate of the shells of the bio-blocks (referred herein after as shell degradation rate) described in the present application was studied in this example.
  • the bio-blocks were prepared using the method described in Example 4.
  • the parameters of the encapsulator e.g., the diameters of the inner nozzle and outer nozzle of the concentric nozzle set) , cells (types and number) , polymeric core material, and polymeric shell material) were adjusted according to the experimental design.
  • the shell degradation rates of the prepared bio-blocks were measured as follows: the bio-blocks were cultured at 37°C in an incubator.
  • the weight of the bio-blocks was determined at specific time points to measure the rate of weight loss of the bio-blocks. Additionally, a degradation curve of the shell of the bio-block can be made by plotting the weight loss rate versus time.
  • Bio-blocks were prepared according to Example 4, wherein HUVEC, HepG2 and MSC cells were used, at a cell density of 4 ⁇ 10 6 /mL, 6 ⁇ 10 6 /mL, or 12 ⁇ 10 6 /mL.
  • the polymeric core material was type I collagen.
  • the polymeric shell material was 5% (w/w) oxidized sodium alginate, with an oxidation level of 2.5%, 4.4%, 8.8%, 17.6%, or 22%.
  • the degradation rates of the shells of the prepared bio-blocks were measured according to the method described above. The results are shown in Table 2 below.
  • Bio-blocks were prepared according to Example 4, wherein the polymeric core material was type I collagen; and the polymeric shell material was oxidized sodium alginate at pre-determined concentrations (5%, 6%, 7%, 8%, 9%, or 10%) , and the oxidation level of oxidized sodium alginate was 8.8%.
  • the shell degradation rates of the prepared bio-blocks were measured according to the method described above. Results are shown in Table 3 below.
  • biodegradable polymers such as sodium alginate
  • SA sodium alginate
  • OSA oxidized sodium alginate
  • Bio-blocks were prepared according to Example 4, wherein the polymeric core material was type I collagen; the polymeric shell material was oxidized sodium alginate at a pre-determined concentration and sodium alginate at a pre-determined concentration.
  • the shell degradation rates of the prepared bio-blocks were measured according to the method described above. Results are shown in Table 4 below.
  • Bio-blocks were prepared according to Example 4, wherein cells used were MSC, HUVEC, HepG2 or fibroblasts.
  • the same cell density e.g., 6 ⁇ 10 6 /mL
  • the same polymeric core material e.g., type I collagen
  • the same polymeric shell material e.g., 5%w/w oxidized sodium alginate with an oxidation level of 8.8%
  • the shell degradation rates of the prepared bio-blocks were measured according to the method described above.
  • bio-blocks having cells with faster growth and proliferation rates had faster shell degradation rates.
  • HUVEC/HepG2 cells grew and proliferated faster than MSC, so under the same conditions, bio-blocks comprising HUVEC/HepG2 cells had a faster shell degradation rate than that of bio-blocks comprising MSC.
  • Bio-blocks were prepared according to Example 4, wherein the cell density used was 4 ⁇ 10 6 /mL, 6 ⁇ 10 6 /mL, 8 ⁇ 10 6 /mL, 12 ⁇ 10 6 /mL, 16 ⁇ 10 6 /mL, or 24 ⁇ 10 6 /mL.
  • the same cell type e.g., HepG2 cells
  • the same polymeric core material e.g., type I collagen
  • the same polymeric shell material e.g., 5%w/w oxidized sodium alginate with an oxidation level of 8.8%
  • the shell degradation rates of the prepared bio-blocks were measured according to the method described above.
  • Bio-blocks were prepared according to Example 4, wherein the same cell type (e.g., HepG2 cells) , the same cell density (e.g., 6 ⁇ 10 6 /mL) , the same polymeric core material (e.g., type I collagen) , and the same polymeric shell material (e.g., 5%w/w oxidized sodium alginate with an oxidation level of 8.8%) were used during the preparation of the bio-blocks, except that shells of different thickness were achieved by adjusting the parameters of encapsulator (e.g., the diameters of the inner nozzle and outer nozzle of the concentric nozzle set) .
  • the shell degradation rates of the prepared bio-blocks were measured according to the method described above.
  • Bio-blocks comprising MSCs, endothelial cells, and tissue-specific cells (such as hepatocytes or smooth muscle cells) , and comprising oxidized alginate in the biodegradable polymeric shell material may have similar shell degradation properties as those described in this example.
  • Example 7 Preparation and characterization of bio-ink compositions.
  • Bio-blocks prepared using the method described in Example 1 was thoroughly mixed with a carrier comprising a bioadhesive material to prepare an exemplary bio-ink composition for bioprinting.
  • Bio-ink compositions comprising bio-blocks comprising MSCs, endothelial cells and optionally tissue-specific cells (such as hepatocytes or smooth muscle cells) can be prepared and characterized similarly.
  • the carrier comprises alginate and gelatin.
  • the carrier comprises alginate and gelatin.
  • the bio-blocks comprise a core comprising HUVEC, and a polymeric core material comprising sodium alginate and type I collagen; and a shell comprising calcium alginate. As the bio-block and the carrier share certain common materials, in order to facilitate visualization, methyl violet was further added to the core of some bio-blocks during the preparation step.
  • the bio-ink composition was visualized using phase contrast microscopy immediately after the bio-ink composition was prepared.
  • Bio-blocks with methyl violet in the cores were stained purple (shown as dark grey in the figure) as shown in FIG. 5A.
  • FIG. 5A further shows that the purple color was present inside the bio-blocks, but not in the carrier (i.e., bio-adhesive material) of the bio-ink, which indicates that the shells preserved the integrity of the contents of the bio-blocks within the bio-ink composition.
  • the bio-ink composition was further bioprinted into a single cell layer with a width of about 250 ⁇ m, and visualized under a phase contrast microscope (FIG. 5B) .
  • the bio-block shown in FIG. 5B was stained purple (shown as dark grey in the figure) .
  • FIG. 5B further shows that the purple color was present inside the bio-block, but not in the carrier (i.e., bio-adhesive material) , which indicates that the shell preserved the integrity of the contents of the bio-block during the bioprinting process.
  • the viscosity of the bio-ink composition was measured as a function of ambient temperature from 25°C to 40°C. As shown in FIG. 6, the viscosity ( ⁇ ) of the carrier (alginate and gelatin) had a viscosity of 30-160 Pa ⁇ s under a temperature of 25°C-40°C. As the temperature increased, the viscosity of the carrier decreased steadily. Additionally, it was discovered that mixing of the bio-blocks and the carrier (i.e. to prepare the bio-ink composition) did not significantly change the viscosity of the composition (data not shown) . Thus, the viscosity of the bio-ink composition is mainly determined by the viscosity of the carrier (such as bio-adhesive material) .
  • the viscosity of the carrier (such as bio-adhesive material) or the bio-ink composition it is possible to control the viscosity of the carrier (such as bio-adhesive material) or the bio-ink composition by adjusting the composition, including content and weight percentage of each component, of the carrier (such as bio-adhesive material) .
  • a bio-ink composition with a viscosity in the range of 1-1000 Pa ⁇ s is compatible with bioprinters. Therefore, the exemplary bio-ink composition described herein can be readily used for bioprinting with known systems in the art at a temperature range of about 4°C to 40°C.
  • Example 8 Characterization of bio-blocks and bio-ink compositions.
  • CaAM (purchased from Invitrogen) was used to stain live cells by staining the cytoplasm, which was visualized as green fluorescence. Specifically, 50 ⁇ g CaAM was dissolved in 10 ⁇ L DMSO, which was then mixed with 10 mL PBS. The final concentration of CaAM in the solution was 5 mmol/L.
  • Propidium iodide (purchased from Invitrogen) was used to stain dead cells by staining the nuclei, which was visualized as red fluorescence. Specifically, propidium iodide nucleic acid stain was diluted in deionized water to 1 mg/mL to be used as a stock solution, which was further diluted at a1: 3000 ratio to a final concentration of 500 nM to be used as a working solution.
  • the staining method was as follows:
  • Bio-blocks prepared using the method of Example 1 were incubated in 1 mL Calcein AM solution at about 37°C for about 1 hours, then transferred to 1 mL Propidium iodide Nucleic Acid Stain for about 15 minutes, and imaged using laser scanning confocal microscopy.
  • the bio-blocks each contained about 100 human umbilical vein endothelial cells (HUVEC) .
  • the polymeric shell material mainly contained calcium alginate
  • the polymeric core material mainly contained sodium alginate and type I collagen. Results are shown in FIG. 7A-7D.
  • FIGs. 7A and 8B Images of the Calcein AM and propidium iodide stained bio-blocks under various conditions, such as immediately after preparation (FIG. 7A) , after storage at 4°C for about 3 hours (FIG. 7B) , after bioprinting (FIG. 7C) , and after incubation at about 37°C for about 72 hours (FIG. 7D) were collected and analyzed using Image-Pro Plus software (Media Cybernetics) .
  • FIGs. 7A and 8B each white circle represented a bio-block.
  • white spots with high saturation levels (such as the spots pointed by the white arrows) represented red fluorescence (i.e. dead cells)
  • white spots with low saturation levels represented green fluorescence (i.e.
  • Red and green pixels in the images were clustered, and various parameters, such as number of red or green spots, area, average optical density, diameter, and accumulated optical density, were statistically analyzed to obtain the number of red and green pixels.
  • FIG. 7A shows that more than about 98%of cells in the bio-blocks were alive in the bio-blocks immediately after preparation.
  • FIG. 7B shows that after storage at 4 °C for 3 hours, cells in the bio-blocks still maintained a high viability (survival rate was 98%) .
  • FIG. 7C shows that after bioprinting of the bio-ink composition comprising the bio-blocks, cells in the bio-blocks still maintained a high viability (survival rate was 97%) .
  • FIG. 7D shows that after incubation in H-DMEM media at 37°C for about 72 hours, cells in the bio-blocks still maintained high viability (survival rate was 95%) .
  • Bio-blocks with human HepG2 cells prepared using the method of Example 1 were cultured at about 37°C with about 5%CO 2 in H-DMEM media containing about 10%FBS (fetal bovine serum) to allow cells to spread, proliferate, and establish connection (i.e. adhere) to each other inside the bio-blocks.
  • the bio-blocks were stained with Calcein AM and propidium iodide as described in the viability section, and imaged by laser scanning confocal microscopy.
  • the bio-blocks were prepared using the method of Example 1.
  • the polymeric shell material mainly contained calcium alginate.
  • the polymeric core material mainly contained sodium alginate and type I collagen. Results are shown in FIGs. 8A-8B.
  • FIG. 8A (40X magnification) shows that after 1 day of incubation, the cells in the bio-blocks were round, and yet to spread.
  • FIG. 8B (200X magnification) shows that after 5 days of incubation, the cells in the bio-blocks adhered and spread.
  • FIGs. 8A-8B demonstrate that cells in the bio-blocks spread and established intercellular connections after incubation for 5 days.
  • Bio-blocks each with about 100 human HepG2 cells were cultured at about 37°C with about 5%CO 2 in H-DMEM media containing about 10%FBS (fetal bovine serum) for about 5 days after preparation to allow proliferation of cells inside the bio-blocks.
  • the cultured bio-blocks were stained with DAPI (blue fluorescence) and 5-Ethynyl-2’ deoxyuridine (EdU, red fluorescence) , and imaged using a laser scanning confocal microscopy.
  • the bio-blocks comprise HepG2 cells.
  • the polymeric shell material mainly contained Calcium alginate
  • the polymeric core material mainly contained sodium alginate and type I collagen.
  • Traditional cell capsules were prepared using a mixture of a sodium alginate solution (such as 2.5% (weight/volume) sodium alginate solution) and cells. The mixture was loaded onto an Encapsulator or a microinjection pump to form microdroplets, which was then exposed to a CaCl 2 solution (such as 0.1 M CaCl 2 solution) to allow crosslinking of the sodium alginate by forming calcium alginate to obtain the traditional cell capsules.
  • a CaCl 2 solution such as 0.1 M CaCl 2 solution
  • the traditional cell capsules lack a core-shell structure in comparison to the bio-blocks.
  • Bio-blocks comprising HepG2 cells were prepared using the method described in Example.
  • the polymeric shell material mainly contained calcium alginate
  • the polymeric core material mainly contained sodium alginate and type I collagen.
  • the cell capsules and bio-blocks were cultured at about 37°C with about 5%CO 2 for about 7 days to allow proliferation of cells inside the bio-blocks or the traditional cell capsules. Before and after culturing for 7 days, the bio-blocks and cell capsules were stained using Calcein and imaged using a laser scanning confocal microscope.
  • FIG. 10A shows cell capsules immediately after preparation.
  • FIG. 10B shows cell capsules after 7 days of culturing. Comparison of FIG. 10A and FIG. 10B reveals that there was no significant proliferation of cells inside the spheroids over the course of culturing. The cells were present as flat and round clusters, which were sparsely distributed in the spheroids after culturing.
  • FIG. 10C shows bio-blocks immediately after preparation
  • FIG. 10D shows bio-blocks after 7 days of culturing.
  • Comparison of FIG. 10C and FIG. 10D reveals significant proliferation of cells inside the bio-blocks over the course of culturing. Additionally, there was clear evidence of cell spreading, adhesion and connection to each other by day 7 of culturing in FIG. 10D.
  • results in FIGs. 10A-10D demonstrate that compared to traditional cell capsules, the bio-blocks of the present application are superior in promoting cell proliferation and establishment of connections among cells. Such properties are significant for subsequent tissue development and formation.
  • FIG. 11A shows connections among HepG2 and HUVEC cells across the borders of multiple bio-blocks forming an integrated structure. White circles mark the approximate boundaries of the original bio-blocks.
  • FIG. 11B provides a close-up view of the connections among HepG2 and HUVEC cells across a border (dark feature pointed out by an arrow) between two bio-blocks. In FIGs.
  • FIG. 11A-11B HepG2 and HUVEC were both labeled with cell tracker Green CMFDA (green signal) .
  • FIG. 11C shows connections between HepG2 cells (overlap of green signals) , between HUVEC cells (overlap of red signals) , and between HepG2 cells and HUVEC cells (overlap of green and red signals resulting in yellow signals) across different bio-blocks.
  • HepG2 cells were labeled with cell tracker Green CMFDA
  • HUVEC cells were labeled with tracker CM-Dil.
  • Bio-blocks comprising MSCs, endothelial cells, and optionally tissue-specific cells (such as hepatocytes or smooth muscle cells) may have similar properties as those described in this example.
  • Example 9 Examples of bio-blocks, bio-ink compositions, and bioprinted constructs.
  • Bio-block is an independent structural and functional unit comprising a shell and a core.
  • bio-blocks comprising different core and/or shell compositions as listed in Table 5 were prepared, and examined under microscopy. Examples of the bio-blocks are shown in FIGs. 2A, and FIGs. 4A-4F.
  • the bio-blocks with shells containing oxidized sodium alginate can be used to stimulate cell proliferation.
  • the bio-blocks with shells containing polylysine can be used to form elaborate structures.
  • Core and shell compositions tested herein may be compatible with the bio-blocks comprising MSCs, endothelial cells and optionally tissue-specific cells (such as hepatocytes or smooth muscle cells) .
  • Bio-blocks comprising various core and shell compositions
  • Bio-blocks have excellent mechanical properties.
  • Bio-blocks prepared using different biodegradable polymeric materials have different mechanical properties.
  • three commonly used cell culturing materials were used to prepare the bio-blocks: (1) alginate as the polymeric shell material, and type I collagen as the polymeric core material; (2) polylysine as the polymeric shell material, and type I collagen as the polymeric core material; and (30 polylysine as the polymeric shell material, and alginate as the polymeric core material.
  • the prepared bio-blocks were each mixed sodium alginate to form the bio-ink compositions respectively.
  • B series 3D bioprinter invented by Sichuan Revotek co., Ltd (FIGs. 12A, 12B) was used to bioprint various bio-ink compositions.
  • a methyl violet dye was further included in the core mixture in order to test the mechanical durability of the bio-blocks in the bio-ink composition. All bio-blocks maintained integrity during the printing process.
  • Bio-blocks have excellent biological properties.
  • Bio-blocks protect cells from damage.
  • Bio-blocks comprising human umbilical vein endothelial cells (HUVEC) , polylysine (Sigma, USA) as the polymeric shell material, and type I collagen (Adranced Biomatrix, US) as the polymeric core material were prepared, and the cells viability was tested under different conditions by staining with Calcein AM (Invitrogen, US) and propidium iodide (Invitrogen, US) , followed by imaging with laser scanning confocal microscopy. The results showed that, cell viability was more than 90%throughout the 3D bioprinting process, including immediately after bio-block preparation (FIG. 13A) , after bioprinting (FIG.
  • Bio-blocks provide a suitable microenvironment for the embedded cells to support normal growth and functions of cells (FIGs. 13E-13I) .
  • polylysine as the polymeric shell material
  • type I collagen as the polymeric core material
  • bio-blocks were prepared and cultured at 37°C with 5%CO 2 in H-DMEM media containing about 10%FBS, and imaged by laser scanning confocal microscopy.
  • Different types of cells were used as the seed cells to test the biological property of bio-blocks, including adhesion, spreading, proliferation, migration, secretion, differentiation, and establishing connections with each other.
  • Bio-blocks comprising HUVECs labeled with cell tracker Green CMFDA (Life Technologies, US) were prepared and cultured for about 24 h. Results show that more than 70%of cells exhibited evidence of adhesion and spreading (FIG. 13E) .
  • Bio-blocks comprising HepG2 cells were prepared and cultured for about 48 h. The cells were actively proliferating as evident in positive 5-Ethynyl-2’ deoxyuridine (EdU) (Life Technologies, US) staining co-localized with the DAPI-stained cell nuclei (FIG. 13F) .
  • EdU deoxyuridine
  • Bio-blocks comprising primary cultured rat hepatocytes were prepared and used to test albumin secretion by staining with an albumin antibody (Life technologies, US) . Results show that hepatocytes in the bio-blocks secreted albumin (FIG. 13G) .
  • Bio-blocks comprising HUVECs labeled with cell tracker Green CMFDA and bio-blocks comprising HepG2 cells labeled with cell tracker CM-Dil were mixed at 1: 1 ratio. Bio-blocks comprising the cell mixture were prepared and cultured for about 72 h. Connections among HUVECs and HepG2 cells in the bio-blocks were observed (FIG. 13H) .
  • Bio-blocks comprising primary cultured rat BMSCs labeled with cell tracker CM-Dil were prepared and cultured for about 4 hours. Free migration of BMSCs in the bio-blocks was observed (FIG. 13I) .
  • Bio-block-based bio-ink is suitable for 3D bioprinting
  • Bio-blocks comprising primary cultured BMSCs and HUVECs mixed at 1: 1 ratio, polylysine labeled with FITC (Sigma, US) as the polymeric shell material, and type I collagen as the polymeric core material were prepared and imaged by laser scanning confocal microscopy (FIG. 14A) .
  • the degradation rate of the shell can be controlled accurately.
  • the shell was degraded completely in 0.25%trypsin (TN, GIBCO, USA) for 10 minutes (min) without interfering with cell viability (FIG. 14B) .
  • the shell was also degraded by cells embedded in the bio-blocks after being cultured at 37°C with 5%CO 2 in H-DMEM media containing about 10%FBS for 9 d (FIG. 14C) .
  • FIG. 14D several bio-blocks integrated together by cells that connected with each other after degradation of the shells.
  • bio-ink comprising the bio-blocks and sodium alginate
  • artificial tissues was bioprinted by a B series 3D bioprinter invented by Sichuan Revotek co., Ltd. According to the structural information of the artificial tissue, the bio-ink was extruded by the jet of the 3D bioprinter to build the artificial tissue (FIGs. 15A, 15B) .
  • the bioprinted structures included a sheet formed by one type of bio-blocks (FIG. 15C) , as well as block-shaped (FIG. 15D) , ring-shaped (FIG. 15E) , and irregular-shaped (FIG. 15F) formed by two or more types of bio-blocks. Accurate cell distribution could be achieved by bioprinting the bio-blocks (FIGs. 15G-I) .
  • a first type of bio-blocks comprising HepG2 cells, type I collagen as the biodegradable polymeric core material, and polylysine as the biodegradable polymeric shell material were prepared.
  • a second type of bio-blocks comprising BMSCs, type I collagen as the biodegradable polymeric core material, and polylysine as the biodegradable polymeric shell material were prepared.
  • Bio-ink compositions comprising each type of bio-blocks were prepared and used to bioprint various artificial tissues according to the structural models in the left panels of FIGs. 16C, 16E, 16G, 16I. The artificial tissues were cultured at 37°Cand with about 5%CO 2 .
  • FIG. 16D The HepG2 cells were stained with cell tracker Green CMFDA (green fluorescence) , and the BMSCs were stained with cell tracker CM Dil (red fluorescence) .
  • the artificial tissues were imaged using a laser scanning confocal microscopy in FIG. 16D, and the right panels of FIGs. 16C, 16E, 16G, and 16I. Histological staining results of the artificial tissues are shown in FIGs. 16F, 16H, and 16J. The imaging results revealed that cells across different bio-blocks fused together (FIGs. 16E-16J) .
  • bio-blocks-based bio-ink provides a unique and efficient medium for engineering biological tissues by bioprinting.
  • the shell of the bio-block provides mechanical support, and the core permits growth, proliferation and differentiation of cells, bio-blocks are suitable for building complex artificial tissues.
  • the core is where the cells live.
  • to manipulate the core is to regulate the microenvironment of the encapsulated cells.
  • biodegradable materials as the major component of the core.
  • multiple aspects of microenvironment e.g., biological factors for growth or differentiation for specific types of cells, spatial structure, mechanical stimulation, PH, temperature and chemical factors
  • FIG. 13A-13I multiple aspects of microenvironment (e.g., biological factors for growth or differentiation for specific types of cells, spatial structure, mechanical stimulation, PH, temperature and chemical factors) could be supplied so that proliferation, differentiation and even interaction among cells are regulated.
  • the shells separate the bio-blocks so that every bio-block has a unique microenvironment if necessary, suggesting that delicate regulation could be achieved by manipulation of individual bio-block.
  • pluripotent stem cells that require sequential manipulation, or multiple cell types that require different microenvironments could be arranged and induced simultaneously in one piece of bioprinted product.
  • bio-blocks could be arranged precisely.
  • Mechanical support provided by the shell not only protects the cells during the process of bioprinting, but also allows complex structure building (FIGs. 12C-12D) .
  • Different mechanical strength could be achieved by manipulating the polymeric shell material, without requiring additional scaffold in 3D bioprinting products.
  • there are fewer restrictions on the bioprinters Shear force caused by interaction between the bio-ink and printer jet nozzle during bioprinting, which represents a major bottleneck in bioprinting (see, for example, Khalil, S., Sun, W. Biopolymer deposition for freeform fabrication of hydrogel tissue constructs. Mater. Sci. Eng. C. 27 (3) , 469-478 (2007) ) , is no longer a threat to the cells. This means more printing trials could be attempted without updating the equipment, and various bioprinting protocols could be explored without worrying about cell damage.
  • the protection and mechanical support provided by the shells enable accurate control of the position of each bio-ink microdroplet by the 3D bioprinter jet during the bioprinting process. All these features make bio-blocks an ideal tool that can be designed and arranged as needed (FIGs. 15G-15I) .
  • bio-blocks can be used as a potent research tool.
  • bio-blocks could be manipulated so that the contents of the core and the shell could provide certain microenvironments for the cells. In that case, various types of (physical, chemical and biological) influences on cells could be studied.
  • multiple bio-blocks could be assembled to establish a more complex microenvironment, imitating a natural environment (maybe even as complex as a pregnancy uterus) . With (almost) every element being controllable, the proliferation and differentiation of stem cells could be further studied.
  • tissue engineering bio-blocks enable seed cells to grow inside a scaffold, which cannot be achieved by known methods in the art that seed cells onto the scaffold. Additionally, targeted therapeutic protein could be incorporated in the shell of bio-blocks, so that the bio-blocks may serve as a delivery vehicle for the targeted therapy.
  • BMSC Primary cultures of rat bone marrow derived stroma cells (BMSCs) were conducted according to a procedure published previously. Briefly, 7 day-old Sprague-Dawley rats were narcotized by ether and then sacrificed and soaked in 75%ethanol to allow degradation for 10 min. The femurs were removed and the soft tissues were cleanly shaved. Both sides of the bones were opened with a rongeur, and the two femurs were placed in 10 ml L-DMEM medium containing 10%FBS.
  • the bone marrow cavity was repeatedly flushed until the bones turned white using medium in a 5-ml sterile syringe.
  • the obtained cell suspension was repeatedly pipetted and mixed, then the cell suspension was seeded in T-75 culture flask, and cultured at 37°C with 5%CO 2 in L-DMEM (GIBCO, US) medium containing 10%FBS. The medium was replaced every 3-4 days.
  • L-DMEM L-DMEM
  • the cells were subsequently digested with 0.25%trypsin containing 0.1%EDTA and subcultured in L-DMEM.
  • Third-generation cells were used in the experiment.
  • Hepatocytes Primary cultures of rat hepatocytes were conducted according to a procedure published previously.
  • livers excised from 1-3 day-old Sprague-Dawley rats were cut into 1.0 mm and digested with 0.125%Trypsin for 15 hat 4 °C, then the mixture was shaken for 15 min, and repeated for 4 times.
  • the animal procedure was approved by the Institutional Animal Care and Use Committee of Sichuan University.
  • the liver tissue digests were suspended in H-DMEM (GIBCO, US) supplemented with antibiotics (GIBCO, US) and 10%FBS (Hyclone, US) .
  • Oxidized sodium alginate preparation The alginate oxidation reaction was carried out in aqueous solution at room temperature for 24 hours. In a dark bottle, 10.00 g of sodium alginate was dissolved in 750 mL of distilled water. To the mixture was added an aqueous solution of 10 mL 0.25 M sodium periodate, reaching a final volume of 1 L with distilled water. The reaction was thoroughly mixed by stirring. After 24 hours, the reaction was quenched by addition of 40 mL ethylene glycol and stirred for 0.5 hour. The oxidized alginate was purified from the quenched reaction mixture by precipitation with the addition of 25 g NaCl and 2L ethanol. The isolated polymer was then dissolved in 1L water and re-precipitated by the addition of 2L ethanol in the presence of NaCl (10 g) . Finally, the precipitate was dried at room temperature under vacuum to obtain oxidized sodium alginate.
  • Bio-block preparation (1) Bio-blocks with simple materials of core and shell were prepared with a culture dish and a micropipette.
  • type I collagen was prepared as described above.
  • 0.05%polylysine solution was prepared by dissolving polylysine (Sigma, Mn150, 000 ⁇ 300, 000) in H-DMEM at pH 7.2, and microdroplets of the bio-block core were prepared by using a micropipette to extrude type I collagen onto the culture dish (e.g., 8 ⁇ l per microdroplet) and solidified at 37°C for 30 min.
  • the solidified core was placed in 0.05%polylysine solution and shaken for 10 min, until polylysine was absorbed onto the core, and the shell formed by self-assembly. More layers of shells were prepared by adding materials with negative charges, such as 0.03%sodium alginate, with repeated shaking in 0.05%polylysine solution for 10 min.
  • Bio-blocks with complex materials of core and shell were prepared with a BUCHI TM Encapsulator B-395 Pro. Take the bio-blocks with type I collagen as the core material and 2.5%oxidative sodium alginate as the shell material as an example.
  • the pH 7.2 type I collagen solution with concentration of about 4 mg/ml was prepared by adding 1 M sodium hydroxide (NaOH) solution on the ice.
  • the 2.5%oxidative sodium alginate was prepared by dissolving oxidative sodium alginate in sterile deionized water.
  • the core material was loaded into a 5 ml injector after mixed with seed cells and the shell material was loaded into a 100 ml culture bottle.
  • a concentric nozzle set with an inner 150 ⁇ m nozzle and an outer 200 ⁇ m nozzle was installed on the Encapsulator.
  • Microdroplets were prepared by using Encapsulator with 400 ⁇ m diameter and solidified in 0.1 M calcium chloride (CaCl 2 ) solution at 37°C for 10 min.
  • Bio-ink preparation and bioprinting Three bio-ink compositions were prepared for bioprinting, including (1) 5 ml 2%alginate (Sigma, USA) containing 1 x 10 6 HUVECs; (2) 5 ml 5%alginate; and (3) 5 ml 2%alginate mixed with HUVECs bio-blocks.
  • B series 3D bioprinter invented by Sichuan Revotek co., Ltd (FIGs. 12A, 12B) was used to jet the bio-inks.
  • the pressure of 3D bioprinter jet was 120 KPa for 5%alginate, 5 KPa for 2%alginate and 40 KPa for 2%alginate mixed with bio-blocks.
  • the temperature of printing inkjet nozzle for all kinds of bio-ink was 37°C and the rate of printing was 300 mm/min. All of the processes were operated on a clean bench at room temperature.
  • Adhesion and spreading Cells were labeled with cell tracker Green CMFDA showing green fluorescence, cell morphology was imaged by laser scanning confocal microscopy.
  • Proliferation Proliferating cells were stained using EdU (red channel) and cell nuclei were stained by DAPI (blue channel) , the images were collected under 200 times magnification using laser scanning confocal microscopy.
  • Migration Cells were stained by CD31 and imaged by laser scanning confocal microscopy for 24 h.
  • Secretion Albumin secreted by hepatocytes in bio-block was tested by albumin test kit. The printed artificial tissue formed by bio-block was fixed in 4%paraformaldehyde.
  • Bioprinted artificial tissue formed by bio-block was cultured at 37°C with 5%CO 2 in H-DMEM containing 10%FBS for 9 d and then was washed with PBS, fixed in 4%paraformaldehyde and embedded in paraffin according to the conventional methods. It was cut into 4- ⁇ m slices and H&E staining were performed according to conventional methods, the results were examined under an inverted optical microscope.
  • HUVECs and hepatocytes in bioprinted artificial tissue using bio-blocks were determined by immunohistochemistry.
  • the bioprinted artificial tissue was cultured at 37°C with 5%CO 2 in H-DMEM containing 10%FBS for 9 d and then was washed with PBS, fixed in 4%paraformaldehyde and embedded in paraffin according to the conventional methods. It was cut into 4- ⁇ m slices.
  • CD31 immunostain (RD, US) was used to detect HUVECs and HNF4 ⁇ immunostain (Santa Cruz, US) was used to detect hepatocytes.
  • the primary antibody of CD31 was goat anti-rat CD31 polyclonal antibody (1: 50) , and the secondary antibody was rabbit anti-goat IgG (1: 500) (Sigma, US) .
  • the primary antibody of HNF4 ⁇ was rabbit anti-rat CD31 polyclonal antibody (1: 200) , and the secondary antibody was goat anti-rabbit IgG (CST, US) .
  • the protocol was based on the manufacturer's instructions, and the results were observed and tested under an inverted optical microscope and photographed.
  • This example describes exemplary methods of preparing two tissues using MSC bio-blocks (i.e., bio-blocks comprising MSC) .
  • MSCs and endothelial cells were mixed at a 10: 1 ratio to provide a cell suspension with a cell concentration of 4x10 6 /ml for use as seed cells in the bio-blocks.
  • Polylysine was used as the polymeric shell material.
  • Type I collagen was used as the polymeric core material.
  • Bio-blocks were prepared using the cell suspension, polymeric core material, and polymeric shell material.
  • MSCs and smooth muscle cells were mixed at a 3: 1 ratio to provide a cell suspension with a cell concentration of 4x10 6 /ml for use as seed cells in the bio-blocks.
  • Polylysine was used as the polymeric shell material.
  • Type I collagen was used as the polymeric core material.
  • Bio-blocks were prepared using the cell suspension, polymeric core material, and polymeric shell material.
  • This method can be used to prepare MSC bio-blocks comprising both endothelial cells and smooth muscle cells by using a cell suspension having MSCs, endothelial cells and smooth muscle cells.
  • MSC bio-blocks comprising smooth muscle cells were bioprinted to form the exterior layers of the tissue-progenitor, and MSC bio-blocks comprising endothelial cells were bioprinted to form the interior layers of the tissue progenitor.
  • the MSC bio-blocks comprising smooth muscle cells provided microenvironments for differentiation of the MSCs to smooth muscle cells.
  • the MSC bio-blocks comprising endothelial cells provided microenvironments for differentiation of the MSCs to endothelial cells.
  • the bioprinted tissue progenitor was cultured in H-DMEM media containing 10%fetal bovine albumin, at 37°C, and 5%CO 2 for 7 days to obtain a tissue having a diameter of about 3 mm.
  • H-DMEM media containing 10%fetal bovine albumin, at 37°C, and 5%CO 2 for 7 days to obtain a tissue having a diameter of about 3 mm.
  • HE staining of the tissue demonstrated that the two types of bio-blocks fused to form an integrated tissue.
  • Immunohistochemical staining results showed that cells were arranged in an orderly fashion according to the pre-determined pattern in the tissue.
  • Example 11 Preparation of MSC bio-blocks comprising endothelial cells.
  • This example describes an exemplary method of preparing MSC bio-blocks using a super-hydrophobic U-bottom plate.
  • Materials and cells used were as follows:
  • Polymeric core material 4mg/mL type I collagen, neutralized with a sterile 1M NaOH solution.
  • Polymeric shell material 1% (w/w) polylysine.
  • HUVEC and MSC mixed at a 1: 10 ratio, with a total cell concentration of 3.7 ⁇ 10 6 cells/mL.
  • the bio-blocks were prepared using the following steps:
  • An alternative cell mixture (such as mixture of MSCs and hepatocytes, mixture of human MSCs and HUVEC, mixture of MSCs, endothelial cells, and smooth muscle cells, mixture of MSCs, endothelial cells, and hepatocytes, etc. ) could be used in place of the mixture of HUVEC and rat MSC in this step to prepare a core mix, which could be used in the following steps to prepare bio-blocks comprising corresponding cell types in the alternative cell mixture.
  • an alternative cell mixture such as mixture of MSCs and hepatocytes, mixture of human MSCs and HUVEC, mixture of MSCs, endothelial cells, and smooth muscle cells, mixture of MSCs, endothelial cells, and hepatocytes, etc.
  • a digital pipetting apparatus that can draw and dispense nanoliter amount of liquid was used to draw 0.1 ⁇ L of the core mix prepared in step (2) , and dispense as microdroplets into a well of the super-hydrophobic U-bottom plate.
  • the microdroplets formed after incubation in the plate at 37°C for 30 minutes.
  • Eppendorf Xplorer 0.5-10 ⁇ L or Transferpette Electronic 0.5-10 ⁇ L system could be used to dispense microdroplets as with a volume as low as 0.1 ⁇ L.
  • an SGE autosampler could be used with a 1 ⁇ L or 0.5 ⁇ L setting to produce 10 or 5 microdroplets at a time, with each microdroplet having a volume of 0.1 ⁇ L.
  • Conical needles could be used for dispensing to improved accuracy.
  • Bio-blocks prepared using the method described in Example 11 were used to bio-print an artificial liver tissue.
  • Each bio-block comprise a mixture of MSCs derived from an adipose tissue and primary hepatocytes as seed cells, type I collagen as the polymeric core material, and polylysine as the polymeric shell material.
  • bio-blocks comprising MSCs derived from an adipose tissue, endothelial cells, and hepatocytes can be used to bioprint an artificial liver tissue having a microvascular network.
  • a bioprinter was used to bioprint the bio-blocks to obtain a tissue progenitor.
  • the tissue progenitor was cultured at 37°C and 5%CO 2 , in H-DMEM medium supplemented with 10%fetal bovine serum for 7 days to obtain the artificial liver tissue.
  • the artificial liver tissue was HE stained and immunohistochemically stained against albumin.
  • the HE staining results demonstrate that cells are arranged as cords in the artificial liver tissue, and the artificial tissue produced a lobular structure which is similar to those found in normal liver tissues.
  • the immunohistochemical staining results revealed that hepatocytes in the interior of the artificial liver tissue could secrete albumin, a liver-specific protein, as in normal liver. Also, non-hepatocytes on the border of the artificial liver tissue did not express albumin.
  • Bio-blocks prepared using the method described in Example 11 were bioprinted using a bioprinter to obtain a construct, which was cultured at 37°C with 5%CO 2 in H-DMEM media containing about 10%FBS for 9 days to obtain an artificial tissue.
  • the bio-printed artificial tissue was sliced and stained with anti-CD31 immunostain. As shown in FIG. 19, a large number of blood capillaries were observed in the bioprinted artificial tissue.
  • bio-blocks of the present application can be used to bioprint constructs having blood capillaries.
  • the blood capillaries the only route for cells in deep tissues to get nutrition and discharge metabolites. It is thus critical for the bioprinted artificial tissues to have blood capillaries in order to connect to the main blood vessels to ensure cell survival.
  • Example 14 Effect of cell types and ratios on blood capillary formation.
  • Bio-blocks comprising various cell compositions as shown in Table 6 were prepared using the method describe din Example 11. The bio-blocks were then bioprinted and cultured using the method described in Example 13 to obtain artificial tissues, which were sliced and stained to observe formation of blood capillaries. The results are shown in FIGs. 20A-20F.
  • Bio-blocks comprising different cell types and ratios.
  • BMSC rat bone marrow-derived mesenchymal stem cell
  • SMC smooth muscle cells
  • HUMSC human MSC.
  • the artificial tissue prepared using such bio-blocks had a large number of blood capillaries (FIG. 20E) .
  • FIG. 20F blood capillaries were observed in the artificial tissues bioprinted using such bio-blocks.
  • HUVEC and human MSC were used as seed cells at a ratio of 3: 1 to prepare bio-blocks (FIG. 20G)
  • blood capillaries were also observed in the artificial tissue bioprinted using such bio-blocks.
  • a plurality of isolated bio-blocks each comprising a mesenchymal stem cell derived from the bone marrow, is prepared.
  • To each of the isolated bio-blocks is added one agent or agent combination that induces differentiation of the stem cell towards or into one of the following four types of cells: osteoblasts, adipocytes, chondrocytes, and myocytes.
  • the plurality of isolated bio-blocks is cultured in the same culturing system, such as in the same container (e.g. culture dish or culture flask) .
  • the cells in each isolated bio-block are observed to evaluate the effects of different microenvironments on stem cell differentiation.
  • the exemplary tissue regeneration method described in this example is particularly useful for repairing a large wound in the skin, as the natural healing process of a large wound in the skin may result in a large scar.
  • a medical imaging method is used to scan the wound to determine the structural information, such as the layers of the skin tissue that is damaged by the wound, including the epithelium, endothelium, and the muscle layer.
  • a digital repair model is constructed based on the structural information of the wound and cell distribution information of the skin tissue.
  • appropriate types of bio-blocks such as fibroblast-containing bio-blocks for the epithelium, and endothelial cell-containing bio-blocks for the endothelium
  • the appropriate bio-blocks are bioprinted directly onto the wound according to the digital repair model.
  • the cells in the bio-blocks are derived from autologous stem cells from the subject having the wound.
  • Cells in the bioprinted bio-blocks proliferate and differentiate within different layers and microenvironments of the wound, forming the corresponding tissue layers and substructures, and repairing the wound in the skin.
  • bio-blocks each comprising a different type of stem cell
  • tissue progenitors are bioprinted using the appropriate batches of bio-blocks.
  • the bioprinted tissue progenitors are cultured in vitro under appropriate conditions to develop into the desired tissues.
  • the cells in the bio-blocks are exposed to a selected agent or agent combination to influence the development of the cells. Cells in the bio-blocks and the tissues are observed throughout the developmental process.
  • Bio-blocks comprising cells derived from a subject that receives the tissue transplant (such as a research animal) are prepared.
  • the tissue progenitor or artificial tissue bioprinted using the bio-blocks is implanted in the subject to observe immune responses to the tissue progenitor or artificial tissue, such as biocompatibility, and immune rejection.
  • Suitable bio-blocks are prepared and used to bioprint an artificial tissue relevant for drug screening.
  • the cells of the bio-blocks used in the preparation process may be derived from the subject (such as a human subject) that receives a drug (including different dosages, formulations etc. ) .
  • the artificial tissue is exposed to a panel of drugs at a pre-determined dosage to evaluate the efficacy of each drug.
  • the artificial tissue is exposed to the drug at different dosages to determine the efficacy of the drug dosage.
  • the drug and the dosage with the highest efficacy and/or lowest side effects are recommended to the subject for treating a disease or condition that affects the tissue.
  • the artificial tissue relevant to the function of the drug is bioprinted using appropriate bio-blocks.
  • the artificial tissue may be a healthy tissue, or a diseased tissue, depending on manipulations during the preparation process, for example, the source of cells in the bio-blocks, the agent (s) or the stimulus included in the bio-blocks, or the culturing conditions.
  • the artificial tissue is exposed to a panel of compounds, and effects of each compound on a diseased artificial tissue are optionally compared to the effects of the same compound on a corresponding healthy artificial tissue, in order to determine the efficacy of each compound on treating a particular disease or condition related to the tissue. Toxicity of each compound is also evaluated based on the effects of the compound on the artificial tissue (such as a healthy artificial tissue) .
  • the compound with the highest efficacy and/or the lowest toxicity, or the best tradeoff between efficacy and toxicity is chosen as a lead compound for further drug discovery and development processes.

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Abstract

L'invention concerne un bio-bloc utile pour la bio-impression et le génie tissulaire, des compositions comprenant le bio-bloc, des procédés de préparation du bio-bloc, des procédés d'utilisation du bio-bloc, et des constructions préparées à l'aide du bio-bloc ou de compositions de bio-encre. Le bio-bloc comprend un noyau contenant une cellule endothéliale et une enveloppe.
PCT/CN2016/078638 2015-04-07 2016-04-07 Bio-blocs comprenant des cellules endothéliales et leurs procédés d'utilisation WO2016161941A1 (fr)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109971703A (zh) * 2019-04-04 2019-07-05 上海科医联创生物科技有限公司 一种自体组织工程表皮的培养方法及其培养基
JP2020509736A (ja) * 2016-11-23 2020-04-02 バロリゼーション−エイチエスジェイ リミテッド パートナーシップＶａｌｏｒｉｓａｔｉｏｎ−Ｈｓｊ， Ｌｉｍｉｔｅｄ Ｐａｒｔｎｅｒｓｈｉｐ 被包化肝組織
WO2021087613A1 (fr) * 2019-11-08 2021-05-14 Polyvalor, Limited Partnership Système de culture cellulaire 3d personnalisable comprenant des cellules incorporées dans un hydrogel et utilisations associées
US11141510B2 (en) 2015-04-07 2021-10-12 Revotek Co., Ltd. Compositions for cell-based three dimensional printing
US11224680B2 (en) 2015-04-07 2022-01-18 Revotek Co., Ltd Compositions for cell-based three dimensional printing

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060198865A1 (en) * 2005-03-07 2006-09-07 Freyman Toby M Microencapsulated compositions for endoluminal tissue engineering
JP2012120696A (ja) * 2010-12-08 2012-06-28 Univ Of Tokyo 血管様構造物を含む三次元細胞培養物
CN103756955A (zh) * 2014-01-22 2014-04-30 清华大学 一种个性化仿生复合结构及其制备和用于药物筛选的方法
KR101472045B1 (ko) * 2013-08-16 2014-12-23 단국대학교 산학협력단 코어-쉘 섬유상 세포전달체 및 이를 포함하는 골조직 또는 연골조직 재생용 조성물

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060198865A1 (en) * 2005-03-07 2006-09-07 Freyman Toby M Microencapsulated compositions for endoluminal tissue engineering
JP2012120696A (ja) * 2010-12-08 2012-06-28 Univ Of Tokyo 血管様構造物を含む三次元細胞培養物
KR101472045B1 (ko) * 2013-08-16 2014-12-23 단국대학교 산학협력단 코어-쉘 섬유상 세포전달체 및 이를 포함하는 골조직 또는 연골조직 재생용 조성물
CN103756955A (zh) * 2014-01-22 2014-04-30 清华大学 一种个性化仿生复合结构及其制备和用于药物筛选的方法

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11141510B2 (en) 2015-04-07 2021-10-12 Revotek Co., Ltd. Compositions for cell-based three dimensional printing
US11224680B2 (en) 2015-04-07 2022-01-18 Revotek Co., Ltd Compositions for cell-based three dimensional printing
JP2020509736A (ja) * 2016-11-23 2020-04-02 バロリゼーション−エイチエスジェイ リミテッド パートナーシップＶａｌｏｒｉｓａｔｉｏｎ−Ｈｓｊ， Ｌｉｍｉｔｅｄ Ｐａｒｔｎｅｒｓｈｉｐ 被包化肝組織
US11492595B2 (en) 2016-11-23 2022-11-08 Morphocell Technologies Inc. Encapsulated liver tissue
CN109971703A (zh) * 2019-04-04 2019-07-05 上海科医联创生物科技有限公司 一种自体组织工程表皮的培养方法及其培养基
WO2021087613A1 (fr) * 2019-11-08 2021-05-14 Polyvalor, Limited Partnership Système de culture cellulaire 3d personnalisable comprenant des cellules incorporées dans un hydrogel et utilisations associées

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