US20210402064A1 - Nanofiber-hydrogel composites for enhanced soft tissue replacement and regeneration - Google Patents

Nanofiber-hydrogel composites for enhanced soft tissue replacement and regeneration Download PDF

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US20210402064A1
US20210402064A1 US17/054,161 US201917054161A US2021402064A1 US 20210402064 A1 US20210402064 A1 US 20210402064A1 US 201917054161 A US201917054161 A US 201917054161A US 2021402064 A1 US2021402064 A1 US 2021402064A1
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microbeads
hydrogel
tissue
composite
population
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Russell Martin
Sashank Reddy
Kevin Colbert
Hai-quan Mao
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Johns Hopkins University
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Assigned to THE JOHNS HOPKINS UNIVERSITY reassignment THE JOHNS HOPKINS UNIVERSITY ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: REDDY, SASHANK, MAO, HAI-QUAN, MARTIN, RUSSELL, COLBERT, Kevin
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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
    • A61L27/56—Porous materials, e.g. foams or sponges
    • 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
    • A61L27/20—Polysaccharides
    • 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
    • A61L27/3604—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 characterised by the human or animal origin of the biological material, e.g. hair, fascia, fish scales, silk, shellac, pericardium, pleura, renal tissue, amniotic membrane, parenchymal tissue, fetal tissue, muscle tissue, fat tissue, enamel
    • A61L27/3633—Extracellular matrix [ECM]
    • 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
    • A61L27/40—Composite materials, i.e. containing one material dispersed in a matrix of the same or different material
    • A61L27/44—Composite materials, i.e. containing one material dispersed in a matrix of the same or different material having a macromolecular matrix
    • A61L27/48—Composite materials, i.e. containing one material dispersed in a matrix of the same or different material having a macromolecular matrix with macromolecular fillers
    • 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
    • A61L27/52—Hydrogels or hydrocolloids
    • 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
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L5/00—Compositions of polysaccharides or of their derivatives not provided for in groups C08L1/00 or C08L3/00
    • C08L5/08—Chitin; Chondroitin sulfate; Hyaluronic acid; Derivatives thereof
    • 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
    • A61L2300/00—Biologically active materials used in bandages, wound dressings, absorbent pads or medical devices
    • A61L2300/20—Biologically active materials used in bandages, wound dressings, absorbent pads or medical devices containing or releasing organic materials
    • A61L2300/23—Carbohydrates
    • A61L2300/236—Glycosaminoglycans, e.g. heparin, hyaluronic acid, chondroitin
    • 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
    • A61L2300/00—Biologically active materials used in bandages, wound dressings, absorbent pads or medical devices
    • A61L2300/60—Biologically active materials used in bandages, wound dressings, absorbent pads or medical devices characterised by a special physical form
    • A61L2300/62—Encapsulated active agents, e.g. emulsified droplets
    • 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
    • A61L2400/00—Materials characterised by their function or physical properties
    • A61L2400/06—Flowable or injectable implant compositions
    • 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
    • A61L2400/00—Materials characterised by their function or physical properties
    • A61L2400/12—Nanosized materials, e.g. nanofibres, nanoparticles, nanowires, nanotubes; Nanostructured surfaces
    • 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
    • A61L2430/00—Materials or treatment for tissue regeneration
    • A61L2430/34—Materials or treatment for tissue regeneration for soft tissue reconstruction

Definitions

  • the present disclosure relates to composite materials and methods that restore lost soft tissue volume while promoting soft tissue regeneration.
  • the present invention also relates to composite materials and methods for cosmetic, and reconstructive purposes.
  • Soft tissue defects resulting from trauma, oncologic resection, or congenital malformation are difficult to treat by conventional means.
  • Current therapies including tissue rearrangements or tissue transfer, cause donor site defects.
  • Other therapies such as prosthetic implants, lead to fibrosis and encapsulation.
  • Existing strategies to promote tissue ingrowth are also inadequate for the treatment of soft tissue defects.
  • Current acellular matrices result in flat, fibrotic sheets of tissue rather than the soft, three-dimensional tissue required for ideal reconstructions.
  • fat grafting can restore soft tissue defects, its wider use is hampered by variable graft survival and limited volumes of restoration.
  • An ideal approach to soft tissue reconstruction would encourage regeneration of soft tissues such as adipose tissue in vivo followed by implantation of the tissues to promote regeneration.
  • tissue regrowth requires a suitable matrix for cells to attach, migrate, proliferate, differentiation, and organize into new tissue.
  • Much of the native extracellular matrix (ECM) is missing at the repair site. Therefore, recreating a synthetic matrix that not only immediately restores the lost tissue volume, but also reconditions the microenvironment, supports host cell infiltration, and encourages regeneration of soft tissue, becomes an essential task when repairing soft tissue defects using adipose tissue-based reconstruction.
  • Hydrogels have received significant interest as ECM mimics due to their high water content and water-swollen networks that allow for facile transport of water-soluble biomolecules. Therefore, hydrogels offer several advantages as a filler material for soft tissue reconstruction.
  • adipocyte progenitors and endothelial progenitors are not able to penetrate and grow into the scaffolds.
  • scarring and fibrous tissue formation are typical because ingrowth of host tissue occurs too slowly, or at least at a pace slower than the absorption of the fiber material.
  • nanofibers have been developed to serve as ECM mimics to support various cell activities.
  • FDA-compliant synthetic biodegradable poly- ⁇ -esters such as polycaprolactone (PCL) or poly(lactide-co-glycolide) (PLGA) can be used to generate nanofibers through a process known as electrospinning
  • PCL polycaprolactone
  • PLGA poly(lactide-co-glycolide)
  • electrospinning Biodegradable sutures and implants prepared from these polymers have been widely used clinically due to their excellent track record on biocompatibility.
  • Various nanofibers of varying diameters and topographies for stem cell engineering applications have been developed. These nanofibers, however, do not offer macroscopic structures, making them difficult to use as 3D scaffolds.
  • compositions and methods in the following disclosure have been designed to addresses this need by using compositions comprising fiber-hydrogel composites such as fiber-hydrogel composite microbeads that possess improved properties (e.g., improved qualities for reconstruction of soft tissue, as detailed further infra).
  • fiber-hydrogel composites such as fiber-hydrogel composite microbeads that possess improved properties (e.g., improved qualities for reconstruction of soft tissue, as detailed further infra).
  • a population of substantially non-spherical microbeads comprising a functionalized hyaluronic acid network covalently linked to a plurality of polycaprolactone fibers having a mean length of less than about 200 micrometers, and a crosslinking agent present at a concentration from about 1 mg/mL to about 25 mg/mL, wherein the mean size of the microbeads is within the range of about 50 micrometers to about 300 micrometers along the longest dimension, wherein the microbeads are pre-reacted, wherein the microbeads are substantially stable at room temperature for at least about 6 months.
  • a lyophilized formulation comprising a population of substantially non-spherical microbeads comprising a functionalized hyaluronic acid network covalently linked to a plurality of polycaprolactone fibers having a mean length of less than about 200 micrometers, and a crosslinking agent present at a concentration from about 1 mg/mL to about 25 mg/mL, wherein the microbeads are pre-reacted, wherein the microbeads comprise a moisture content of less than about 15%, wherein the microbeads are substantially stable at room temperature for at least about 12 months.
  • the microbeads are substantially non-inflammatory.
  • the functionalized hyaluronic acid comprises acrylated hyaluronic acid
  • the crosslinking agent comprises thiolated poly(ethylene glycol), or a derivative thereof.
  • the functionalized hyaluronic acid comprises thiolated hyaluronic acid
  • the crosslinking agent comprises poly(ethylene glycol) diacrylate (PEGDA), or a derivative thereof.
  • the plurality of polycaprolactone fibers comprises an electrospun fiber.
  • the diameter of the polycaprolactone fibers is within the range of about 100 nanometers to about 5 micrometers.
  • the microbeads has a mean storage modulus of between about 50 Pa and about 2500 Pa.
  • the microbeads comprises plurality of pores.
  • the pores are disposed throughout the hyaluronic acid network such that it promotes tissue growth and cell infiltration when administered into a target tissue of a subject.
  • the plurality of pores comprises an area density of no less than about 50 pores per cm 2 , with at least about 80% of pores having a mean size of no less than about 5 micrometers.
  • an implantable or injectable biomaterial comprising the population of microbeads, wherein the biomaterial is formulated for dermal or subdermal administration into a target tissue of a subject.
  • a formulation comprising the biomaterial, wherein the formulation is suitable for dermal injection via a needle no larger than 16-gauge, 18-gauge, 20-gauge, 22-gauge, 24-gauge, 26-gauge, 27-gauge, 28-gauge, 29-gauge, 30-gauge, 31-gauge, or smaller than 31-gauge.
  • a further aspect of the invention provides a kit comprising a syringe comprising from about 0.1 mL to about 20 mL of the microbeads, wherein said microbeads are formulated as i) substantially dehydrated beads or ii) hydrated beads that are ready for injection into a target tissue of a subject.
  • An additional aspect of the invention provides a formulation comprising the population of microbeads, wherein the microbeads are lyophilized to form dehydrated microbeads, and wherein the dehydrated microbeads are suitable for reconstitution with water, saline solution or suitable reconstitution fluid to substantially replace the water mass lost (as measured by weight) prior to administration into a target tissue of a subject such that when the water mass lost is replaced, the concentration of the microbeads in the reconstitution fluid is the same or substantially the same as the concentration of microbeads before lyophilization.
  • the formulation wherein the dehydrated microbeads retain or regain its beaded form upon reconstitution by water, saline solution or suitable reconstitution fluid prior to administrating into a target tissue of a subject in need thereof.
  • the formulation wherein the dehydrated microbeads are substantially stable at room temperature for at least about 12 months.
  • kits for preparation of the population of microbeads for immediate administration into a target tissue of a subject comprising: a vial containing the microbeads, said microbeads having been lyophilized and formed into powder cakes, wherein the lyophilized powder cakes are able to be reconstituted by water, saline solution or suitable reconstitution fluid.
  • a further aspect of the invention provides a kit for preparation of the population of microbeads for immediate injection into a target tissue of a subject, the kit comprising: (i) a syringe comprising the microbeads formulated as lyophilized gel beads; and (ii) a vial comprising water, saline solution or suitable reconstitution fluid, wherein water, saline solution or suitable reconstitution fluid is capable of being drawn up from the vial into the syringe, whereby the lyophilized microbeads are rehydrated.
  • a further aspect of the invention provides a kit for preparation of the population of microbeads for immediate injection into a target tissue of a subject, the kit comprising: (i) a syringe comprising the microbeads; and (ii) a vial comprising water, saline solution or suitable reconstitution fluid, wherein water, saline solution or suitable reconstitution fluid is capable of being drawn up from the vial into the syringe, whereby the lyophilized microbeads are rehydrated.
  • a further aspect of the invention provides the population of microbeads further comprising a compound selected from the group consisting of growth factors, compounds stimulating angiogenesis, immun
  • a further aspect of the invention provides omodulators, inhibitors of inflammation, and combinations thereof.
  • Another aspect of the invention provides the population of microbeads further comprising a compound that have therapeutic effects, vascularization effects, anti-vascularization effects, anti-inflammatory effects, anti-bacterial effects, antihistamine effects, and combinations thereof.
  • the population of microbeads further comprises a processed tissue extracellular matrix, wherein the processed tissue extracellular matrix is derivable from an adipose tissue.
  • a further aspect of the invention provides a method for performing a cosmetic procedure or a reconstructive procedure or reducing or reversing a tissue defect resulting from trauma, surgical intervention, or an age-associated disease, disorder or condition, comprising injecting into the tissue and/or the tissue defect a population of substantially non-spherical microbeads comprising a functionalized hyaluronic acid network covalently linked to a plurality of polycaprolactone fibers having a mean length of less than about 200 micrometers, and a crosslinking agent present at a concentration from about 1 mg/mL to about 25 mg/mL, wherein the mean size of the microbeads is within the range of about 50 micrometers to about 300 micrometers along the longest dimension, wherein the microbeads are pre-reacted, wherein the microbeads are substantially stable at room temperature for at least about 6 months.
  • Another aspect of the invention provides a population of substantially non-spherical microbeads comprising a functionalized hydrogel network covalently linked to a plurality of polymeric fibers having a mean length of less than about 200 micrometers, and a crosslinking agent present at a concentration from about 1 mg/mL to about 25 mg/mL,
  • the polymeric fiber, or fragments thereof comprises a synthetic polymeric material comprising a poly(lactic-co-glycolic acid), poly(lactic acid), and/or a polycaprolactone, or a combination or derivatives thereof; or a biological polymeric material selected from the group consisting of a silk, collagen, elastin, hyaluronic acid, chitosan, a derivative thereof, or a combination thereof.
  • the hydrogel material comprises a poly(ethylene glycol), a collagen, a dextran, an elastin, an alginate, a hyaluronic acid, a poly(vinyl alcohol), a derivative thereof, or a combination thereof.
  • any one of the embodiments described herein are contemplated to be able to combine with any other one or more embodiments, even though the embodiments are described under different aspects of the invention.
  • FIG. 1 is a set of images showing post-injection inflammatory responses.
  • FIG. 1A depicts a comparison of the inflammatory response at post-injection day 1 for gels containing thiolated HA (HA-SH)+diacrylated polyethylene glycol (PEGDA) (crosslinking agent) (upward-pointing arrows) compared to gels containing acrylated HA (HA-Ac)+thiolated polyethylene glycol (PEGSH, downward-pointing arrow).
  • FIG. 1B shows images from the inflammation study in a porcine inner thigh model at Day 0 (center panel) and Day 2 (right panel). The left panel shows the identity of the composite in each s.c. injection corresponding to the pattern shown on the inner thigh images.
  • FIG. 1A depicts a comparison of the inflammatory response at post-injection day 1 for gels containing thiolated HA (HA-SH)+diacrylated polyethylene glycol (PEGDA) (crosslinking agent) (upward-
  • FIG. 1C shows the histological response to key groups in the porcine inner thigh model 48 hours after implantation.
  • the blue staining indicates hyaluronic acid, and the red staining indicates immune cell staining.
  • the injection site is encapsulated with a definitive boarder between host tissue and injection site in the thiolated-HA group, as visualized by the monocyte activation on the periphery of the injection site, which depicts a strong acute immune response to this HA group.
  • FIG. 1D is a graph showing the shear storage modulus (in Pa) for the LS stiff and soft composites and relevant commercial controls.
  • FIG. 2 is four optical microscopy images of the LS beaded composite after 100 ⁇ dilution to image individual beads.
  • FIG. 2A shows the composite after being particularized into 250-micron diameter beads;
  • FIG. 2B shows the composite after being lyophilized and rehydrated, illustrating that the composite retains its original appearance;
  • FIG. 2C is a 10 ⁇ image depicting nanofiber and hydrogel components of the beaded formulation;
  • FIG. 2D is an optical microscopy image of the beaded formulation in a non-diluted state.
  • FIG. 2E shows the non-effect of beading and lyophilization on the storage modulus.
  • FIG. 2F is a schematic for generation of composite microbeads.
  • FIG. 2A shows the composite after being particularized into 250-micron diameter beads
  • FIG. 2B shows the composite after being lyophilized and rehydrated, illustrating that the composite retains its original appearance
  • FIG. 2C is a 10 ⁇ image depicting nanofiber and hydrogel components of the beaded
  • FIG. 2G is a microscopy image of beads with 75 um sieve (left), 150 ⁇ m sieve (middle), 250 um sieve (right).
  • FIG. 2H demonstrates beads of size ⁇ 75 ⁇ m, ⁇ 150 ⁇ m and ⁇ 200 ⁇ m by measuring the longest axis within the particle. Further characterized beads distribution was performed using image analysis program that will use edge detection for more consistent measurements.
  • FIG. 2G is a micros
  • FIG. 2I is a injection force curve showing displacement under certain pressure to assess injectability of the composite depending on their bead size.
  • the syringes filled with 150 ⁇ m and 75 ⁇ m beads were loaded into a syringe fixture (Instron) attached to a MTS Criterion 43 mechanical tester.
  • the gel was injected out of the syringe through a 27 gauge needle (1 ⁇ 2′′ length, BD) at a crosshead speed of 1 mm/sec.
  • the 150 ⁇ m and 75 ⁇ m groups both resulted in acceptable injection profiles.
  • FIG. 4 is two graphs showing analysis of the composite LS-1.
  • FIG. 4A shows volume retention for the beaded composite compared to commercial controls as assessed by MRI quantification.
  • FIG. 4B shows the effect of HA molecular weight (MW) on shear storage modulus of the composite prepared under the same HA concentration and fiber loading as used in 4 A.
  • FIG. 4C shows the effect of HA concentration (mg/ml) on shear storage modulus of the composite prepared under the same HA MW and fiber loading conditions;
  • FIG. 4D shows the effect of HA concentration (mg/ml) on compression storage modulus of the composite prepared under the same HA MW and fiber loading conditions;
  • FIG. 4E shows volume retention of scaffolds with variation in properties (see Table 1), demonstrating the tunability of the composite.
  • FIG. 5 is a series of MRI images showing new tissue infiltrating a LS9 scaffold injection site, as compared to a competitor product.
  • FIG. 5A shows 0% tissue ingrowth on Day 14, 30, and 50 post-injection with JUVÉDERM® filler, demonstrating the lack of host cell tissue ingrowth in this product.
  • FIG. 5B shows tissue ingrowth after injection of the LS-9 formulation: 18% new tissue at Day 14, 52% new tissue at Day 30, and 84% new tissue at Day 50.
  • FIG. 6 shows the results of swelling assessment of a pre-formed LS beaded composite compared to marketed controls.
  • FIG. 6A shows images of the pre-formed composite (lower left injection) in comparison with JUVÉDERM (lower right injection) at day 0 and day 2 with both image (top panels) and MRI cross section (bottom panels).
  • FIG. 6B shows pairwise graphical comparison of the swelling effect on day 0 (left bars) and day 2 (right bars) of JUVÉDERM® VOLUMA XC® (left pair), ULTRA PLUS XC® (center pair) and LS beads (right pair).
  • FIG. 6C is a graph showing that the LS-9 composite differentiates itself from market comparables by limiting post-procedural swelling and maximizing host tissue ingrowth.
  • FIG. 7 is two graphs showing stiffness ( FIG. 7A ) and tan delta ( FIG. 7B ) for soft tissue injectables (quantifies the balance between energy loss and storage. A higher Tan ⁇ indicates more liquid-like properties, whereas lower tan ⁇ suggests more solid-like properties, regardless of the modulus or viscosity).
  • FIG. 7C is three images showing a comparison of the composite (top left) with native human fat (bottom left). The two materials are shown side by side in the right panel.
  • FIG. 8 depicts development of a lyophilized form of the beaded composite.
  • FIGS. 8A-C show optical microscopy images of the LS beaded composite. HA-Ac, nanofibers, and 5 k 2-arm PEGSH are formulated in PBS and reacted overnight.
  • FIG. 8A is an image of the composite before the overnight reaction (“pre-beading”);
  • FIG. 8B is an image of the composite after bead formation (“Beads”);
  • FIG. 8C is an image of the composite after lyophilization and rehydration (“Post-lyophilization”).
  • FIG. 8D is a graph showing measurement of shear storage modulus for each of 8 A- 8 C, demonstrating the increased stability of the beaded composite compared to the bulk composite.
  • FIG. 9 is two graphs showing shear elastic moduli ( FIG. 9A ) and compression elastic moduli ( FIG. 9B ) for pre-beading, beaded, and post-lyophilization samples of the improved lyophilization process.
  • FIG. 11 shows a method for synthetic soft tissue generation.
  • FIG. 11A shows the general procedure for creating defects in the inguinal fat pad in a rabbit model.
  • FIG. 11B shows host blood vessel infiltration into different graft matrices (150-Pa composite, 150-Pa hydrogel, and 80-Pa hydrogel) on POD 14. Endothelial cells were stained with CD31 in red and cell nuclei were stained with DAPI in blue. Fibers were F8BT-labelled in green. Scale bar: 100 ⁇ m.
  • FIG. 12 shows the histological analysis (H&E-stained) in rat model at POD 13 weeks after injection of LS-5. It is clearly observed that the growth/infiltration pattern of the cells, which recapitulate the underlying bead morphology.
  • the present invention relates to pre-reacted, beaded composite materials comprising a hydrogel and a nanostructure for use in methods for reconstruction of soft tissue.
  • the invention also relates to methods for repairing or reconstructing a soft tissue injury using a composition comprising a scaffold complex comprising a biomaterial covalently linked to a biodegradable fiber.
  • the invention in other aspects also relates to a method of fabricating a composition for use in soft tissue reconstruction where the composition comprises a hydrogel and a nanostructure disposed therein.
  • an element means one element or more than one element.
  • “about” can mean plus or minus less than 1 or 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, or greater than 30 percent, depending upon the situation and known or knowable by one skilled in the art.
  • subject or “subjects” or “individuals” may include, but are not limited to, mammals such as humans or non-human mammals, e.g., domesticated, agricultural or wild, animals, as well as birds, and aquatic animals.
  • biologically active material refers to any organic or inorganic agent that is biologically active, i.e. it induces a statistically significant biological response in a living tissue, organ or organism.
  • the biologically active agent can be a medicine, peptide, polysaccharide or a polynucleotide, e.g. DNA and RNA. It can be an agent for treatment of diseases in therapeutic areas like alimentary/metabolic, blood and clotting, cardiovascular, dermatological, genitourinary, hormonal, immunological, infection, cancer, musculoskeletal, neurological, parasitic, ophthalmic, respiratory and sensory. It can further be for treatment of diseases like osteoporosis, epilepsy, Parkinson's disease, pain and cognitive dysfunction.
  • It can be an agent for the treatment of hormonal dysfunction diseases or hormonal treatment e.g. for contraception, hormonal replacement therapy or treatment with steroidal hormones. It can further be an agent such as an antibiotic or antiviral, anti-inflammatory, neuroprotective, prophylactic vaccine, memory enhancer, analgesic (or analgesic combination), immunosuppressant, antidiabetic or an antiviral. It can be an antiasthmatic, anticonvulsant, antidepressant, antidiabetic, or antineoplastic. It can be an antipsychotic, antispasmodic, anticholinergic, sympathomimetic, antiarrhythmic, antihypertensive, or diuretics. It can be an agent for pain relief or sedation.
  • the agent can also be a tranquilliser or a drug for cognitive dysfunction.
  • the agent can be in a free acid or base form, a salt or a neutral compound. It can be a peptide, e.g. levodopa; or an antibody fragment. It can be a polynucleotide, a soluble ion or a salt.
  • a “scaffold complex” includes any covalent association of two components: a polymeric fiber and a hydrogel material.
  • the scaffold complex contains the polymeric fiber and hydrogel material in a “functional network”, meaning that the interactions between components results in a chemical, biochemical, biophysical, physical, or physiological benefit.
  • a functional network may include additional components, including cells, biological materials (e.g., polypeptides, nucleic acids, lipids, carbohydrates), therapeutic compounds, synthetic molecules, and the like.
  • the scaffold complex promotes tissue growth and cell infiltration when implanted into a target tissue present in a human subject.
  • hydrogel is a type of “gel,” and refers to a water-swellable polymeric matrix, consisting of a three-dimensional network of macromolecules (e.g., hydrophilic polymers, hydrophobic polymers, blends thereof) held together by covalent or non-covalent crosslinks that can absorb a substantial amount of water (e.g., 50%, 60% 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99% or greater than 99% per unit of non-water molecule) to form an elastic gel.
  • the polymeric matrix may be formed of any suitable synthetic or naturally occurring polymer material.
  • gel refers to a solid three-dimensional network that spans the volume of a liquid medium and ensnares it through surface tension effects. This internal network structure may result from physical bonds (physical gels) or chemical bonds (chemical gels), as well as crystallites or other junctions that remain intact within the extending fluid. Virtually any fluid can be used as an extender including water (hydrogels), oil, and air (aerogel). Both by weight and volume, gels are mostly fluid in composition and thus exhibit densities similar to those of their constituent liquids.
  • a hydrogel is a type of gel that uses water as a liquid medium.
  • hydrophobic and hydrophilic polymers are based on the amount of water vapor absorbed by polymers at 100% relative humidity. According to this classification, hydrophobic polymers absorb only up to 1% water at 100% relative humidity (“rh”), while moderately hydrophilic polymers absorb 1-10% water, hydrophilic polymers are capable of absorbing more than 10% of water, and hygroscopic polymers absorb more than 20% of water.
  • rh relative humidity
  • hydrophilic polymers are capable of absorbing more than 10% of water
  • hygroscopic polymers absorb more than 20% of water.
  • a “water-swellable” polymer is one that absorbs an amount of water greater than at least 50% of its own weight, upon immersion in an aqueous medium.
  • crosslinked refers to a composition containing intramolecular and/or intermolecular crosslinks, whether arising through covalent or noncovalent bonding, and may be direct or include a cross-linker.
  • Noncovalent bonding includes both hydrogen bonding and electrostatic (ionic) bonding.
  • polymer includes linear and branched polymer structures, and also encompasses crosslinked polymers as well as copolymers (which may or may not be crosslinked), thus including block copolymers, alternating copolymers, random copolymers, and the like.
  • oligomers are polymers having a molecular weight below about 1000 Da, preferably below about 800 Da. Polymers and oligomers may be naturally occurring or obtained from synthetic sources.
  • microbead means a particle of the invention material of less than 300 ⁇ m in the longest dimension.
  • processed tissue extracellular matrix means an extracellular matrix (ECM) taken from an animal subject, preferably human, and processed to disinfect and remove cells.
  • ECM extracellular matrix
  • biomaterial means an organic material that has been engineered to interact with biological systems.
  • a biomaterial is a hydrogel.
  • biomaterial is a bacterially derived hyaluronic acid.
  • biodegradable refers to a material that can be broken down by biological means in a subject.
  • the term “storage modulus” is used to define the measurement of the elastic components of the dynamic modulus which illustrates how the material responds to deformation or stress.
  • “deformation” means the change in shape or size of an object due to applied force.
  • the term “shear modulus” also known as the modulus of rigidity, denoted by G, is defined as the ratio of shear stress to the shear strain.
  • shear stress means the component of stress coplanar with a material cross section.
  • shear strain means the force perpendicular to the material cross section.
  • the term “implantable” means able to be formulated for implantation via a syringe to a subject.
  • soft tissue refers to tissues that connect, support, or surround other structures and organs of the body. Soft tissue includes muscles, tendons, ligaments, fascia, nerves, fibrous tissues, fat, blood vessels, and synovial membranes.
  • stable refers to a material that does not degrade at room temperature.
  • autologous refers to any material derived from the same individual to whom it is later to be re-introduced into the individual.
  • allogeneic or, alternatively, “allogenic,” refers to any material derived from a different animal of the same species or different patient as the individual to whom the material is introduced.
  • lyophilized refers to a material after undergoing a lyophilization, which is a process used for preserving materials by removing the water from the material, which involves first freezing the material and then drying it, under a vacuum, at very low temperatures.
  • the term “functionalized” refers to a material that is uniformly or non-uniformly modified so as to have a functional chemical moiety associated therewith (e.g., chemically modified).
  • functional chemical moiety is capable of reacting to permit the formation of a covalent or non-covalent bond.
  • functional chemical moiety can provide the material improved properties.
  • Prosthetic implants are prone to foreign-body response leading to fibrosis and encapsulation ⁇ Calobrace 2014 Plastic and Reconstructive Surgery, 134(1 Suppl), 6S-11; Tsoi 2014 . Plastic and Reconstructive Surgery, 133(2), 234-249 ⁇ . Fat grafting involving placement of adipocytes harvested during liposuction is limited to small volumes and is hampered by poor graft survival ⁇ Kakagia 2014 Surgical Innovation, 21(3), 327-336; Largo 2014 British Journal of Plastic Surgery, 67(4), 437-448 ⁇ .
  • injectable hydrogel soft tissue fillers can be used, but these are suitable only for smaller defects.
  • the volume restoration provided by existing fillers is transient ⁇ Young 2011 . Acta Biomaterialia, 7(3), 1040-1049; Varma 2014 Acta Biomaterialia, 10(12), 4996-5004 ⁇ .
  • a new generation of tissue engineering solutions has been proposed to focus on using hydrogel scaffolds as templates to regenerate soft tissues such as adipose tissue at the site of reconstruction.
  • Adipose-derived stem cells have been identified in wound beds surrounding soft tissue defects ⁇ Salibian 2013 Archives of plastic surgery 40.6: 666-675 ⁇ . They can be differentiated into soft tissues such as fat, when supported with a suitable matrix microenvironment. Therefore strategies to fill the repair site with functional materials have the potential to enable the regeneration of new tissue using the endogenous ASCs or using ASCs and/or other mesenchymal cells present in liposuction aspirates that are readily obtainable using standard surgical practices. Hydrogels have been widely studied as a scaffold matrix for the regeneration of tissue defects due to their three-dimensional (3D) nature and elastic properties, which are similar to those of soft tissues.
  • 3D three-dimensional
  • hydrogel scaffolds to promote cellular infiltration is the key to successful soft tissue restoration. Lack of vascular infiltration is responsible for the failure of large-volume fat grafting and other tissue engineering attempts. No currently available materials can fill the volume lost in soft tissue defects while promoting early vascularization and ASC differentiation to regenerate soft tissue.
  • Porosity and pore size of the implant materials can influence host biological responses because of their effect on macrophage infiltration and activities.
  • Several studies have shown that skewed polarization of macrophages triggered by pore features and mechanical property of the scaffold can influence the degree of fibrosis and scar formation (M1 macrophage-dominant response) versus angiogenesis and matrix remodeling (M2 macrophage-dominant response).
  • Porous materials implanted in soft tissues compared with nonporous implants, modulated pro-regenerative polarization of macrophages, promoted angiogenesis, and reduced fibrosis and scar formation. Therefore, the ability for hydrogel scaffolds to promote cellular infiltration and vascular ingrowth is key to modulating acute and chronic inflammation, promoting tissue remodeling, angiogenesis, and regen-eration, and achieving a long-lasting soft tissue restoration.
  • HA hyaluronic acid
  • CCRR IKVAV WLC laminin-derived loop peptide
  • this hydrogel when injected on day 3 after the CCI injury, promoted significant vasculature network formation filling the lesion site (>10 mm) at 4 weeks to 6 months post implantation.
  • This improved angiogenesis was attributed to the ability of this hydrogel to retain and present tissue-secreted growth factors, particularly vascular endothelial growth factor (VEGF).
  • VEGF vascular endothelial growth factor
  • Literature reports also revealed that small HA degradation fragments of 3-10 disaccharide units were potent regulators of endothelial cell proliferation, migration, tubule formation, and angiogenesis ⁇ Slevin 2002 Journal of Biological Chemistry, 277(43), 41046-41059 ⁇ .
  • this HA hydrogel delivered robust vascular formation inside the scaffold matrix following transplantation. Regenerated blood vessels grew into the lesion and penetrated through the implanted matrix, and supported the survival and growth the neuronal progenitors. These results confirmed the unique ability of this optimized HA hydrogel composition in promoting host vascular ingrowth. More importantly, the hydrogel matrix is sufficiently porous to allow robust cell migration inside the hydrogel matrix.
  • the hydrogel of this invention is a substantially purified hyaluronic acid (HA), preferably produced by a bacterium.
  • a scaffold matrix that combines hydrogel materials or other biomaterials with polymeric fibers, formulated such that the density, ratio of gel to fibers, and other properties are variable, while maintaining sufficient porosity and strength.
  • a scaffold matrix comprising materials that contain and/or are isolated from a processed tissue extracellular matrix, such as extracellular matrix derived and/or derivable from an adipose tissue.
  • hydrogel materials are functionalized.
  • hydrogel materials are functionalized with groups comprising hydroxyl, amino, carboxyl, thio, acrylate, sulfonate, phosphate, amide, as well as modified forms thereof, such as activated or protected forms.
  • hydrogel material comprises a hyaluronic acid (HA).
  • hydrogel material comprises functionalized hyaluronic acid (HA).
  • hydrogel material comprises acrylated hyaluronic acid (HA).
  • hydrogel material comprises thiolated hyaluronic acid (HA).
  • the scaffold complexes suitable for use medical devices that are incorporated into a tissue of a human subject to whom the complexes are administered, e.g., by injection or implantation.
  • the scaffold complexes contain a polymeric fiber, generally having a mean diameter of from about 10 nm to about 10,000 nm, such as about 100 nm to about 8000 nm, or about 150 nm to about 5,000 nm, or about 100, 150, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800, 900, 1,000, 1,500, 2,000, 2,500, 3,000, 3,500, 4,000, 4,500, 5,000, 5,500, 6,000, 6,500, 7,000, 7,500, or 8,000.
  • the polymeric fiber generally has a mean length of from about 10 ⁇ m to about 500 such as about 10, 50, 100, 150, 200, 250, 300, 350, 400, 450, or 500
  • the length of the fibers is determined using optical fluorescence microscopy.
  • the length of the fibers is determined using electron microscopy.
  • fibers are functionalized. In some embodiments, fibers are functionalized with groups comprising hydroxyl, amino, carboxyl, thio, acrylate, sulfonate, phosphate, maleimide, amide, as well as modified forms thereof, such as activated or protected forms.
  • the ratio of polymeric fiber to hydrogel material can be determined my any means known in the art.
  • the ratio of polymeric fiber to hydrogel material is from about 1:100 to about 100:1 on a component-mass basis, such as about 1:50 to about 50:1, or 1:10 to about 10:1, such as 1:5 to about 5:1, such as about 1:3 to about 3:1.
  • the ratio of polymeric fiber to hydrogel material is also provided as a concentration basis, e.g., a given weight of polymeric fiber per volume of hydrogel material.
  • the concentration is from about 1 to 50 mg/mL.
  • the hydrogel material is generally disposed on the polymer fiber, such as being bonded to the outer surface (or an outer surface, depending upon the composition and shape) of the polymer fiber.
  • the scaffold complex is not generally a uniform solid material. Instead, scaffold complexes contain a plurality of pores present on or within a surface of the scaffold complex. The presence, size, distribution, frequency and other parameters of the pores can be modulated during the creation of the scaffold complex.
  • Pore size can be from below about 1 ⁇ m to up to 100 ⁇ ms, including 1, 2, 3, 4 5, 10, 15, 20, 30, 40, 50, 60 70, 80, 90 or 100 ⁇ ms, and the size thereof may be narrowly tailored, e.g., such that at least 40%, such as 50%, 60%, 70%, 80%, 90%, 95% or greater than 95% of the pores are in a desired size or within a desired size range.
  • the scaffold complexes of the invention are suitable for incorporation into a tissue of a human subject, and thus they are generally “biocompatible”, meaning capable of interacting with a biological system (such as found in a human subject) without inducing a pathophysiological response therein and/or thereby.
  • the scaffold complex is provided in order to be durably retained in the tissue.
  • the scaffold complexes are transiently retained in the human subject and are provided as substantially biodegradable.
  • a polymeric fiber contains a biocompatible biodegradable polyester.
  • the polymeric fiber contains polycaprolactone.
  • one preferred form of interaction of the complex containing polymer fiber and hydrogel includes a crosslinking moiety, generally present in an amount effective to introduce bonding between polymer fiber and hydrogel material, e.g., to induce crosslinking between polycaprolactone fiber and hyaluronic acid.
  • the composite concept has been widely used as a material-reinforcement mechanism. For example, adding hydroxyapatite particles into hydrogel can increase its stiffness ⁇ Wu 2008 Materials Chemistry and Physics 107.2 (2008): 364-369 ⁇ , and the composite tensile modulus increases even more for elongated particles ⁇ Yusong 2007 Journal of Materials Science, 42(13), 5129-5134 ⁇ . Electrospun nanofiber meshes have been used widely as a tissue engineering substrate due to their topographical similarity to the native ECM. Of particular interest, the decellularized ECM of adipose tissue is highly fibrous and porous in nature ( FIG. 6G ) ⁇ Young 2011 . Acta Biomaterialia, 7(3), 1040-1049 ⁇ .
  • an electrospun fiber-hydrogel composite that offers superior properties as compared to other scaffolds is provided.
  • nanofibers and a hydrogel matrix which has been reported previously ⁇ Coburn 2011 Smart Structures and Systems, 7(3), 213 ⁇ , introduced here are interfacial bonding between fiber surfaces and the hydrogel crosslinking network ( FIG. 6 ).
  • Such a composite design not only allows stronger mechanical reinforcement from the solid fiber component, but also allows independent tuning of bulk mechanical properties and the average pore size/porosity of the hydrogel phase, enabling both optimal cell infiltration properties and structural integrity.
  • fibers can be employed as preferred cell adhesion substrates for ASCs and endothelial progenitors, therefore acting as a guide to support cell migration and ASC differentiation.
  • the nanoparticle-hydrogel scaffold matrix is formed as a bulk composite gel.
  • improvements including introducing the composite as a beaded gel. This allows for the user to vary the bead properties in order to get desirable results (Table 1, FIGS. 4B, 4C, and 4D ) and improves the storage modulus of the composite ( FIG. 3 ).
  • the current invention introduces a system of particulation wherein the pre-formed hydrogel-nanofiber composite is physically modulated, such as by being pushed through one, two, three, or more than three mesh screens, creating a population of nonspherical beads that are relatively similar to one another in shape and size. This two-screen system allows for tight control over the size of the beads, thus allowing the user to modulate the size as needed (Table 1).
  • the invention described comprises a complex that is reacted prior to injection or prior to storage.
  • the components of the formulation were mixed by the end-user immediately prior to injection into a subject. This introduced complications of human factors, e.g. the user preparation and handling that this necessitated. Varying mixing and wait times can change the reaction time and thus significantly alter the stiffness of the complex. This could cause the gel to be too stiff to be injected through a syringe, or not stiff enough, which would create undesirable properties when injected into a subject.
  • the inventors developed a pre-reacted composition, wherein the reaction (e.g gelation) takes place prior to storage.
  • the formulation comprising 7 mg/mL HA-Ac, 8 to 10 mg/mL of fibers with maleimide, and 6.9 m/mL of PEGSH, is fully reacted in bulk at 37° C.
  • the inventors By pre-reacting the gel during manufacturing, the inventors removed the need to protect the labile functional groups and removed the need for extensive mixing and curing by the end-user.
  • the present invention includes a step of lyophilization prior to storage of the complex.
  • the introduction of lyophilization allows for storage of the product at room temperature for extended periods of time without loss of function.
  • the beaded product is lyophilized in an isotonic solution of sucrose, Trehalose, and sodium chloride. These variables protect the microstructure during the drying process and extend the product's shelf life.
  • the lyophilized gel beads are reconstituted with water after storage, allowing them to be ready for injection within seconds.
  • the mechanical properties of the nanofiber phase of the fiber-hydrogel composite do not substantially change in the dried or frozen state, as opposed to most hydrogel components.
  • the fiber fraction can help maintain the overall composite microstructure.
  • the composite With the correct lyophilization cycle and formulation, the composite can be lyophilized, while still remaining as distinct beads upon rehydration.
  • a key innovation is the reduction in inflammation achieved by optimizing the chemistry in the in-situ forming of this composite material.
  • the inventors have improved the invention in comparison to previous work by identifying the chemical properties that cause inflammation in a subject, and creating compositions with new properties that reduced this problem.
  • Previous embodiments of this invention used thiolated-HA (HA-SH) and an acrylated PEG crosslinker (PEGDA). This had a negative response in subjects, including acute immune response as shown in FIG. 1C , and inflammation after injection ( FIGS. 1A and 1B ).
  • HA-Ac acrylated HA
  • PEGSH thiolated PEG crosslinking agent
  • a key innovation is the incorporation of cell-binding or tissue-binding moieties into the nanofiber-hydrogel composite material.
  • These moieties including peptides, aptamers, antibodies, small molecules, or other binding reagents confer enhanced ability of the composite to incorporate cells from the local wound environment or exogenously provided cells.
  • the resultant integral structure of bound nanofibers, hydrogel, and cells behaves more like native tissue than the nanofiber-hydrogel composite alone.
  • the incorporated cellular elements including adipocytes, endothelial cells, perictyes, and other mesenchymal cells can better interface with and remodel the nanofiber-hydrogel composite as well as surrounding tissues to effect a more natural and durable repair.
  • a key innovation is the association of cells to the nanofiber-hydrogel composite material.
  • the associated cellular elements including adipocytes, endothelial cells, perictyes, and other mesenchymal cells can better interface with and remodel the nanofiber-hydrogel composite as well as surrounding tissues to effect a more natural and durable repair while providing a suitable mechanical strength to mimic ECM.
  • a key innovation is the association of tissue to the nanofiber-hydrogel composite material.
  • the associated tissue such as adipose tissue can better interface with and remodel the nanofiber-hydrogel composite as well as surrounding tissues to effect a more natural and durable repair while providing a suitable mechanical strength to mimic ECM.
  • a key innovation of the current invention is the stability of the complex at room temperature (between 15° C. (59° F.) and 18° C. (64° F.)).
  • a problem faced by many commercially available hydrogel- or hyaluronic acid-based fillers is the necessity to be stored in cool conditions. This limits the amount of time they can be stored, thus shortening the window in which the end-user can administer the product to a subject.
  • An objective of the invention herein is improved storage stability. The creation of a pre-reacted, beaded formulation that can be lyophilized and rehydrated for administration addresses this unmet need.
  • the invention provides the crosslinking and interfacial bonding between nanofibers and polymer network in the hydrogel component. This is important for the formation of a “true” composite. It was demonstrated that blending such fibers and hydrogel did not provide the same degree of mechanical enhancement. There are also previous reports on the use of nanofiber-hydrogel blends. In other words, the crosslinking and interfacial bonding importantly differentiates this new work from the art. Furthermore, the interfacial bonding could include covalent bonds as shown in this manuscript, and secondary bonding, such as hydrogen bonds and electrostatic charge interaction.
  • the invention provides mesenchymal cell binding elements in the nanofiber-hydrogel composites that can enhance the ability of the resultant composite to recruit, capture, and/or embed mesenchymal cells.
  • the resultant material consisting of both cells and nanofiber-hydrogel composite can behave more like native tissue and can effect more natural and durable repair than the nanofiber-hydrogel composite alone.
  • the invention provides mesenchymal cells incorporated into the composite structure.
  • these cells can be obtained from liposuction aspirates in routine clinical practice by those skilled in the art.
  • Such cells including adipocytes, mesenchymal stem cells, endothelial precursors, adipocyte precursors, endothelial cells, and pericytes can be incorporated into the nanofiber-hydrogel composite to generate novel materials that resemble native soft tissue.
  • the work presented herein defines a scaffold complex that is formulated into non-spherical microbeads. This beading improves the storage stability of the gel and allows for variation of other properties that can improve the function of the complex and differentiate the qualities for different purposes.
  • the work presented herein defines a scaffold complex that is reacted prior to injection, in order to reduce the possibility of end-user error.
  • In situ forming of the composite introduces the complication of human factors, including the user preparation and handling that it necessitates. Mixing and wait times on the order of minute affect properties of the formulation, such as undesirable stiffness and elasticity ( FIGS. 12A and 12B ).
  • the invention herein introduces the step of lyophilizing the beaded scaffold complex, allowing it to be stable when stored at room temperature ( FIG. 11 ).
  • the beads can be rehydrated prior to use within seconds, while maintaining their original properties.
  • Existing HA fillers can't be irradiated for sterilization because the aqueous environment enables too much HA chain scission. Lyophilizing the product prior to storage not only allows for the composition to be stored for longer periods of time, but also enables additional terminal sterilization modalities, i.e. irradiation via gamma or e-beam.
  • the work presented herein defines the components used for the formation of composite to be a hydrogel network with sufficient pore size and porosity (around the beads and within the beads) for cell migration and host tissue ingrowth, and nanofibers which loosely include polymer fibers with diameters ranging from 50 nm to 10 ⁇ m.
  • the scaffold complex of the invention is a composite comprising a hydrogel.
  • the hydrogel can include any type of suitable hydrogel component.
  • the invention contemplates nanostructure/gel composites that include any suitable gel component, including any suitable hydrogel component known in the art.
  • the gel and/or hydrogels can be formed of any suitable synthetic or naturally-occurring materials.
  • the polymer component of the gels and/or hydrogels can comprise a cellulose ester, for example, cellulose acetate, cellulose acetate propionate (CAP), cellulose acetate butyrate (CAB), cellulose propionate (CP), cellulose butyrate (CB), cellulose propionate butyrate (CPB), cellulose diacetate (CDA), cellulose triacetate (CTA), or the like.
  • cellulose esters are described in U.S. Pat. Nos. 1,698,049, 1,683,347, 1,880,808, 1,880,560, 1,984,147, 2,129,052, and 3,617,201, and may be prepared using techniques known in the art or obtained commercially.
  • cellulose esters suitable herein include CA 320, CA 398, CAB 381, CAB 551, CAB 553, CAP 482, CAP 504, all available from Eastman Chemical Company, Kingsport, Tenn. Such cellulose esters typically have a number average molecular weight of between about 10,000 and about 75,000.
  • the cellulose esters and comprise a mixture of cellulose and cellulose ester monomer units; for example, commercially available cellulose acetate butyrate contains cellulose acetate monomer units as well as cellulose butyrate monomer units and unesterified cellulose units.
  • the gels/hydrogels of the invention may also be comprised of other water-swellable polymers, such as acrylate polymers, which are generally formed from acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, and/or other vinyl monomers.
  • acrylate polymers are those copolymers available under the tradename “EUDRAGIT®” from Rohm Pharma (Germany), as indicated, supra.
  • the Eudragit series E, L, S, RL, RS and NE copolymers are available as solubilized in organic solvent, in an aqueous dispersion, or as a dry powder.
  • Preferred acrylate polymers are copolymers of methacrylic acid and methyl methacrylate, such as the Eudragit L and Eudragit S series polymers. Particularly preferred such copolymers are Eudragit L-30D-55 and Eudragit L-100-55 (the latter copolymer is a spray-dried form of Eudragit L-30D-55 that can be reconstituted with water).
  • the molecular weight of the Eudragit L-30D-55 and Eudragit L-100-55 copolymer is approximately 135,000 Da, with a ratio of free carboxyl groups to ester groups of approximately 1:1.
  • the copolymer is generally insoluble in aqueous fluids having a pH below 5.5.
  • Eudragit S-100 Another particularly suitable methacrylic acid-methyl methacrylate copolymer is Eudragit S-100, which differs from Eudragit L-30D-55 in that the ratio of free carboxyl groups to ester groups is approximately 1:2.
  • Eudragit S-100 is insoluble at pH below 5.5, but unlike Eudragit L-30D-55, is poorly soluble in aqueous fluids having a pH in the range of 5.5 to 7.0. This copolymer is soluble at pH 7.0 and above.
  • Eudragit L-100 may also be used, which has a pH-dependent solubility profile between that of Eudragit L-30D-55 and Eudragit S-100, insofar as it is insoluble at a pH below 6.0. It will be appreciated by those skilled in the art that Eudragit L-30D-55, L-100-55, L-100, and S-100 can be replaced with other acceptable polymers having similar pH-dependent solubility characteristics.
  • the composite materials of the invention can be based on hyaluronic acid (HA) as the hydrogel material.
  • HA is a non-sulfated, linear polysaccharide with repeating disaccharide units which form the hydrogel component.
  • HA is also a non-immunogenic, native component of the extracellular matrix in human tissues, and widely used as a dermal filler in aesthetic and reconstructive procedures.
  • hyaluronic acid are functionalized.
  • hyaluronic acid are functionalized with groups comprising hydroxyl, amino, carboxyl, thio, acrylate, sulfonate, phosphate, amide, as well as modified forms thereof, such as activated or protected forms.
  • HA hydrogels have been investigated as potential matrices for cell delivery in a variety of models of cell and tissue injury. These hydrogels can serve as a protective and supporting scaffold for cells and can also reduce scarring. Thus, it is believed HA has a critical role in enhancing tissue regeneration by promoting cell infiltration and promoting angiogenesis.
  • the material has three-dimensional integrity and a consistency similar to that of native fat tissue. This renders it suitable for off-the-shelf restoration of missing soft tissue volume.
  • the material preferably may be deposited with a plurality of flexible nanofibers that can serve as substrates for migration of adipocytes and endothelial progenitors.
  • the material has sufficient porosity to allow these precursor cells to rapidly infiltrate and integrate into the scaffold rather than forming a fibrous capsule around it.
  • the HA hydrogel component provides compressibility and volumetric expansion while also providing important angiogenic cues.
  • the nanofiber and hydrogel components are biodegradable allowing them to be replaced by regenerated soft tissue. Sixth, all component materials have strong safety track records in numerous FDA-approved devices, potentially reducing regulatory hurdles for clinical translation.
  • the molecular weight of hyaluronic acid affects the overall properties of the composite ( FIG. 4B ). Allergan and other dermal filler manufacturers also recognize the significance of HA molecular weight on product persistence. Allergan's Juvederm products are manufactured with a 2.5 MDa molecular weight HA. Further, in Juvederm patent U.S. Pat. No. 8,450,475 B2, Allergan elaborates, “In a typical embodiment of the invention, the ratio of high molecular weight to low molecular weight HA is at least about, and preferably greater than 2 (w/w ⁇ 2) with the high molecular weight HA having a molecular weight of above 1.0 MDa.”
  • HA hyaluronic acid
  • U.S. Pat. No. 6,921,819 a process for cross-linking solid hyaluronic acid (HA) by reacting it with a polyfunctional linker during hydration of the HA
  • U.S. Pat. No. 6,685,963 acrylic particles of HA
  • U.S. publication 200610194758 a method for making a hydrogel by cross linking high and low molecular weight sodium HAs
  • U.S. publication 2009/0036403 cross-linking HA with a tetra functional PEG epoxide to provide “tunably” cross-linked HA
  • U.S. publications 2009/0143331 (a HA dermal filler with a degradation inhibitor, such as chondroitin sulphate, in order to provide a longer lasting filler); U.S. publication 2009/0143348 (HA combined with a steroid); and U.S. publication 2009/0155314 (HA combined with a botulinum toxin). Additionally, U.S. publications 2009/0148527, 2009/0093755, and 2009/0022808 disclose HA in microspheres, cross-linked with collagen, and coated with a protein, respectively.
  • a degradation inhibitor such as chondroitin sulphate
  • HA include: WO 2009/034559 (a process for aesthetic and/or reparative treatment of the skin with compositions that contain at least one C-glycoside derivative); WO 2009/024719 (cosmetic and pharmaceutical compositions that contain HA and a C-glycoside derivative useful for filling recesses/depressions in the skin, restore volume of the body or the face, and to reduce the sign of aging); WO 2007/128923 (a method for preparing a biocompatible gel with controlled release of one or more active lipophilic and/or amphiphilic ingredients); U.S.
  • U.S. Pat. No. 3,763,009 a process for improving the oxidation resistance of ascorbic acid by subjecting a mixture of ascorbic acid, maltose and/or oligosaccharides to an enzyme derived from genera Aspergillus, Penicillium or others to enzymatically convert the mixture into ascorbic acid glucoside
  • 5,616,611 a ⁇ -Glycosyl-L-ascorbic acid that exhibits no direct reducing activity, is stable, and is useful as a stabilizer, quality-improving agent, antioxidant, physiologically active agent, a UV-absorbent in pharmaceutical and cosmetic industries
  • U.S. Pat. No. 5,843,907 the production and use of a crystalline 2-O- ⁇ -D-glucopyranosyl-L-ascorbic acid suitable for vitamin C enriching agents, food stuffs, pharmaceuticals, and cosmetics
  • EP 0539196 an industrial scale preparation of high purity 2-O- ⁇ -D-glucopyranosyl-L-ascorbic acid
  • Commercial products incorporating HA and/or vitamin C agents include: MESOGLOW® products, REVITACARE®, and NCTF® 135/135HA Mesotherapy products.
  • the HA of the invention is a sterilized HA derived from bacterial fermentation.
  • Hyaluronic acid can be produced by Group A and C strains of Streptococcus bacteria.
  • bacteria such as Streptococcus zooepidemicus synthesise HA as a means to encapsulate their cells and exhibit molecular mimicry to escape detection from the host's immune system (Boyce J D, Chung J Y, Adler B, J Biotechnol. 2000 Sep. 29; 83(1-2):153-60; Wessels M R, Moses A E, Goldberg J B, DiCesare T J, Proc Natl Acad Sci USA. 1991 Oct.
  • HA is also naturally produced by other pathogenic bacteria including Streptococcus pyogenes, Streptococcus uberis, Pasteurella multocida and Cryptococcus neoformans (Blank L M, Hugenholtz P, Nielsen L K J Mol Evol. 2008 July; 67(1):13-22; DeAngelis P L, Jing W, Drake R R, Achyuthan A M, J Biol Chem. 1998 Apr.
  • any of the herein-described gel/hydrogel compositions may be utilized so as to contain an active agent and thereby act as an active agent delivery system when applied to a body surface (e.g., a site of tissue repair) in active agent-transmitting relation thereto.
  • the release of active agents “loaded” into the present hydrogel compositions of the invention typically involves both absorption of water and desorption of the agent via a swelling-controlled diffusion mechanism.
  • Active agent-containing hydrogel compositions may be employed, by way of example, in transdermal drug delivery systems, in wound dressings, in topical pharmaceutical formulations, in implanted drug delivery systems, in oral dosage forms, and the like.
  • Suitable active agents that may be incorporated into the present hydrogel compositions and delivered systemically (e.g., with a transdermal, oral, or other dosage form suitable for systemic administration of a drug) include, but are not limited to: analeptic agents; analgesic agents; anesthetic agents; antiarthritic agents; respiratory drugs, including antiasthmatic agents; anticancer agents, including antineoplastic drugs; anticholinergics; anticonvulsants; antidepressants; antidiabetic agents; antidiarrheals; antihelminthics; antihistamines; antihyperlipidemic agents; antihypertensive agents; anti-infective agents such as antibiotics and antiviral agents; antiinflammatory agents; antimigraine preparations; antinauseants; antiparkinsonism drugs; antipruritics; antipsychotics; antipyretics; antispasmodics; antitubercular agents; antiulcer agents; antiviral agents; anxiolytics; appetite suppressants;
  • Specific active agents with which the present adhesive compositions are useful include, without limitation, anabasine, capsaicin, isosorbide dinitrate, aminostigmine, nitroglycerine, verapamil, propranolol, silabolin, foridone, clonidine, cytisine, phenazepam, nifedipine, fluacizin, and salbutamol.
  • suitable active agents include, by way of example, the following:
  • Suitable bacteriostatic and bactericidal agents include, by way of example: halogen compounds such as iodine, iodopovidone complexes (i.e., complexes of PVP and iodine, also referred to as “povidine” and available under the tradename Betadine from Purdue Frederick), iodide salts, chloramine, chlorohexidine, and sodium hypochlorite; silver and silver-containing compounds such as sulfadiazine, silver protein acetyltannate, silver nitrate, silver acetate, silver lactate, silver sulfate and silver chloride; organotin compounds such as tri-n-butyltin benzoate; zinc and zinc salts; oxidants, such as hydrogen peroxide and potassium permanganate; aryl mercury compounds, such as phenylmercury borate or merbromin; alkyl mercury compounds, such as thiomers
  • Suitable antibiotic agents include, but are not limited to, antibiotics of the lincomycin family (referring to a class of antibiotic agents originally recovered from Streptomyces lincolnensis ), antibiotics of the tetracycline family (referring to a class of antibiotic agents originally recovered from Streptomyces aureofaciens ), and sulfur-based antibiotics, i.e., sulfonamides.
  • Exemplary antibiotics of the lincomycin family include lincomycin, clindamycin, related compounds as described, for example, in U.S. Pat. Nos. 3,475,407, 3,509,127, 3,544,551 and 3,513,155, and pharmacologically acceptable salts and esters thereof.
  • antibiotics of the tetracycline family include tetracycline itself, chlortetracycline, oxytetracycline, tetracycline, demeclocycline, rolitetracycline, methacycline and doxycycline and their pharmaceutically acceptable salts and esters, particularly acid addition salts such as the hydrochloride salt.
  • Exemplary sulfur-based antibiotics include, but are not limited to, the sulfonamides sulfacetamide, sulfobenzimide, sulfadiazine, sulfadoxine, sulfamerazine, sulfamethazine, sulfamethizole, sulfamethoxazole, and pharmacologically acceptable salts and esters thereof, e.g., sulfacetamide sodium.
  • Suitable pain relieving agents are local anesthetics, including, but not limited to, acetamidoeugenol, alfadolone acetate, alfaxalone, amucaine, amolanone, amylocaine, benoxinate, betoxycaine, biphenamine, bupivacaine, burethamine, butacaine, butaben, butanilicaine, buthalital, butoxycaine, carticaine, 2-chloroprocaine, cinchocaine, cocaethylene, cocaine, cyclomethycaine, dibucaine, dimethisoquin, dimethocaine, diperadon, dyclonine, ecgonidine, ecgonine, ethyl aminobenzoate, ethyl chloride, etidocaine, etoxadrol, .beta.-eucaine, euprocin, fenalcomine, fomocaine,
  • topical agents that may be delivered using the present hydrogel compositions as drug delivery systems include the following: antifungal agents such as undecylenic acid, tolnaftate, miconazole, griseofulvine, ketoconazole, ciclopirox, clotrimazole and chloroxylenol; keratolytic agents, such as salicylic acid, lactic acid and urea; vessicants such as cantharidin; anti-acne agents such as organic peroxides (e.g., benzoyl peroxide), retinoids (e.g., retinoic acid, adapalene, and tazarotene), sulfonamides (e.g., sodium sulfacetamide), resorcinol, corticosteroids (e.g., triamcinolone), alpha-hydroxy acids (e.g., lactic acid and glycolic acid), alpha-keto acids (e.g., glyoxylic acid), and anti
  • suitable active agents are those useful for the treatment of wounds, and include, but are not limited to bacteriostatic and bactericidal compounds, antibiotic agents, pain relieving agents, vasodilators, tissue-healing enhancing agents, amino acids, proteins, proteolytic enzymes, cytokines, and polypeptide growth factors.
  • a permeation enhancer for topical and transdermal administration of some active agents, and in wound dressings, it may be necessary or desirable to incorporate a permeation enhancer into the hydrogel composition in order to enhance the rate of penetration of the agent into or through the skin.
  • Suitable enhancers include, for example, the following: sulfoxides such as dimethylsulfoxide (DMSO) and decylmethylsulfoxide; ethers such as diethylene glycol monoethyl ether (available commercially as Transcutol) and diethylene glycol monomethyl ether; surfactants such as sodium laurate, sodium lauryl sulfate, cetyltrimethylammonium bromide, benzalkonium chloride, Poloxamer (231, 182, 184), Tween (20, 40, 60, 80) and lecithin (U.S.
  • sulfoxides such as dimethylsulfoxide (DMSO) and decylmethylsulfoxide
  • ethers such as diethylene glyco
  • alcohols such as ethanol, propanol, octanol, decanol, benzyl alcohol, and the like
  • fatty acids such as lauric acid, oleic acid and valeric acid
  • fatty acid esters such as isopropyl myristate, isopropyl palmitate, methylpropionate, and ethyl oleate
  • polyols and esters thereof such as propylene glycol, ethylene glycol, glycerol, butanediol, polyethylene glycol, and polyethylene glycol monolaurate (PEGML; see, e.g., U.S. Pat. No.
  • amides and other nitrogenous compounds such as urea, dimethylacetamide (DMA), dimethylformamide (DMF), 2-pyrrolidone, 1-methyl-2-pyrrolidone, ethanolamine, diethanolamine and triethanolamine; terpenes; alkanones; and organic acids, particularly salicylic acid and salicylates, citric acid and succinic acid. Mixtures of two or more enhancers may also be used.
  • the composite compositions of the invention comprising a gel (e.g., a hydrogel component) and a nanostructure may also comprise additional optional additive components.
  • additional optional additive components are known in the art and can include, for example, fillers, preservatives, pH regulators, softeners, thickeners, pigments, dyes, refractive particles, stabilizers, toughening agents, detackifiers, pharmaceutical agents (e.g., antibiotics, angiogenesis promoters, antifungal agents, immunosuppressing agents, antibodies, and the like), and permeation enhancers.
  • additives, and amounts thereof are selected in such a way that they do not significantly interfere with the desired chemical and physical properties of the hydrogel composition.
  • Absorbent fillers may be advantageously incorporated to control the degree of hydration when the adhesive is on the skin or other body surface.
  • Such fillers can include microcrystalline cellulose, talc, lactose, kaolin, mannitol, colloidal silica, alumina, zinc oxide, titanium oxide, magnesium silicate, magnesium aluminum silicate, hydrophobic starch, calcium sulfate, calcium stearate, calcium phosphate, calcium phosphate dihydrate, woven and non-woven paper and cotton materials.
  • Other suitable fillers are inert, i.e., substantially non-adsorbent, and include, for example, polyethylenes, polypropylenes, polyurethane polyether amide copolymers, polyesters and polyester copolymers, nylon and rayon.
  • compositions can also include one or more preservatives.
  • Preservatives include, by way of example, p-chloro-m-cresol, phenylethyl alcohol, phenoxyethyl alcohol, chlorobutanol, 4-hydroxybenzoic acid methylester, 4-hydroxybenzoic acid propylester, benzalkonium chloride, cetylpyridinium chloride, chlorohexidine diacetate or gluconate, ethanol, and propylene glycol.
  • compositions may also include pH regulating compounds.
  • pH regulators include, but are not limited to, glycerol buffers, citrate buffers, borate buffers, phosphate buffers, or citric acid-phosphate buffers may also be included so as to ensure that the pH of the hydrogel composition is compatible with that of an individual's body surface.
  • compositions may also include suitable softening agents.
  • suitable softeners include citric acid esters, such as triethylcitrate or acetyl triethylcitrate, tartaric acid esters such as dibutyltartrate, glycerol esters such as glycerol diacetate and glycerol triacetate; phthalic acid esters, such as dibutyl phthalate and diethyl phthalate; and/or hydrophilic surfactants, preferably hydrophilic non-ionic surfactants, such as, for example, partial fatty acid esters of sugars, polyethylene glycol fatty acid esters, polyethylene glycol fatty alcohol ethers, and polyethylene glycol sorbitan-fatty acid esters.
  • compositions may also include thickening agents.
  • thickeners herein are naturally occurring compounds or derivatives thereof, and include, by way of example: collagen; galactomannans; starches; starch derivatives and hydrolysates; cellulose derivatives such as methyl cellulose, hydroxypropylcellulose, hydroxyethyl cellulose, and hydroxypropyl methyl cellulose; colloidal silicic acids; and sugars such as lactose, saccharose, fructose and glucose.
  • Synthetic thickeners such as polyvinyl alcohol, vinylpyrrolidone-vinylacetate-copolymers, polyethylene glycols, and polypropylene glycols may also be used.
  • the hydrogel composite of the invention comprising a hydrogel and a nanostructure further comprises a component that promotes angiogenesis.
  • a challenge to achieving clinically relevant soft tissue regeneration prior to the present invention is that the regenerated tissue preferably should be re-vascularized. Therefore, any material that promotes soft tissue regeneration preferably should also encourage angiogenesis.
  • One way to achieve this is through the use of heparin-containing hydrogel components, which can serve as growth factor binding sites to enrich and retain growth factors promoting angiogenesis and tissue formation.
  • the composition further comprises and delivers an antibody.
  • antibody is used herein in its broadest sense and includes certain types of immunoglobulin molecules comprising one or more antigen-binding domains that specifically bind to an antigen or epitope.
  • An antibody specifically includes intact antibodies (e.g., intact immunoglobulins), antibody fragments, and multi-specific antibodies.
  • the antibody comprises an antibody. In some aspects, the antibody is a monoclonal antibody. In some aspects, the antibody is a chimeric antibody. In some aspects, the antibody is a humanized antibody. In some aspects, the antibody is a human antibody. In some aspects, the antibody comprises an antibody fragment. In some embodiments, the antibody comprises an alternative scaffold.
  • full length antibody “intact antibody,” and “whole antibody” are used herein interchangeably to refer to an antibody having a structure substantially similar to a naturally occurring antibody structure and having heavy chains that comprise an Fc region.
  • a “full length antibody” is an antibody that comprises two heavy chains and two light chains.
  • Fc region means the C-terminal region of an immunoglobulin heavy chain that, in naturally occurring antibodies, interacts with Fc receptors and certain proteins of the complement system.
  • the structures of the Fc regions of various immunoglobulins, and the glycosylation sites contained therein, are known in the art. See Schroeder and Cavacini, J. Allergy Clin. Immunol., 2010, 125:S41-52, incorporated by reference in its entirety.
  • the Fc region may be a naturally occurring Fc region, or an Fc region modified as described in the art or elsewhere in this disclosure.
  • the VH and VL regions may be further subdivided into regions of hypervariability (“hypervariable regions (HVRs);” also called “complementarity determining regions” (CDRs)) interspersed with regions that are more conserved.
  • the more conserved regions are called framework regions (FRs).
  • Each VH and VL generally comprises three CDRs and four FRs, arranged in the following order (from N-terminus to C-terminus): FR1-CDR1-FR2-CDR2-FR3-CDR3-FR4.
  • the CDRs are involved in antigen binding, and influence antigen specificity and binding affinity of the antibody. See Kabat et al., Sequences of Proteins of Immunological Interest 5th ed. (1991) Public Health Service, National Institutes of Health, Bethesda, Md., incorporated by reference in its entirety.
  • the light chain from any vertebrate species can be assigned to one of two types, called kappa ( ⁇ ) and lambda ( ⁇ ), based on the sequence of its constant domain.
  • the heavy chain from any vertebrate species can be assigned to one of five different classes (or isotypes): IgA, IgD, IgE, IgG, and IgM. These classes are also designated ⁇ , ⁇ , ⁇ , ⁇ , and ⁇ , respectively.
  • the IgG and IgA classes are further divided into subclasses on the basis of differences in sequence and function. Humans express the following subclasses: IgG1, IgG2, IgG3, IgG4, IgA1, and IgA2.
  • the amino acid sequence boundaries of a CDR can be determined by one of skill in the art using any of a number of known numbering schemes, including those described by Kabat et al., supra (“Kabat” numbering scheme); Al-Lazikani et al., 1997, J. Mol. Biol., 273:927-948 (“Chothia” numbering scheme); MacCallum et al., 1996, J. Mol. Biol. 262:732-745 (“Contact” numbering scheme); Lefranc et al., Dev. Comp. Immunol., 2003, 27:55-77 (“IMGT” numbering scheme); and Honegge and Plückthun, J. Mol. Biol., 2001, 309:657-70 (“AHo” numbering scheme); each of which is incorporated by reference in its entirety.
  • Kabat numbering scheme
  • Al-Lazikani et al. 1997, J. Mol. Biol., 273:927-948
  • Chothia numbering scheme
  • antibody fragment comprises a portion of an intact antibody, such as the antigen-binding or variable region of an intact antibody.
  • Antibody fragments include, for example, Fv fragments, Fab fragments, F(ab′)2 fragments, Fab′ fragments, scFv (sFv) fragments, and scFv-Fc fragments.
  • “Fv” fragments comprise a non-covalently-linked dimer of one heavy chain variable domain and one light chain variable domain.
  • Fab fragments comprise, in addition to the heavy and light chain variable domains, the constant domain of the light chain and the first constant domain (CH1) of the heavy chain.
  • Fab fragments may be generated, for example, by recombinant methods or by papain digestion of a full-length antibody.
  • F(ab′)2 fragments contain two Fab′ fragments joined, near the hinge region, by disulfide bonds.
  • F(ab′)2 fragments may be generated, for example, by recombinant methods or by pepsin digestion of an intact antibody.
  • the F(ab′) fragments can be dissociated, for example, by treatment with 1-mercaptoethanol.
  • Single-chain Fv or “sFv” or “scFv” antibody fragments comprise a VH domain and a VL domain in a single polypeptide chain.
  • the VH and VL are generally linked by a peptide linker.
  • Any suitable linker may be used.
  • the linker is a (GGGGS)n (SEQ ID NO: 127).
  • n 1, 2, 3, 4, 5, or 6.
  • scFv-Fc fragments comprise an scFv attached to an Fc domain.
  • an Fc domain may be attached to the C-terminal of the scFv.
  • the Fc domain may follow the VH or VL, depending on the orientation of the variable domains in the scFv (i.e., VH-VL or VL-VH). Any suitable Fc domain known in the art or described herein may be used.
  • the Fc domain comprises an IgG4 Fc domain.
  • single domain antibody refers to a molecule in which one variable domain of an antibody specifically binds to an antigen without the presence of the other variable domain.
  • Single domain antibodies, and fragments thereof, are described in Arabi Ghahroudi et al., FEBS Letters, 1998, 414:521-526 and Muyldermans et al., Trends in Biochem. Sci., 2001, 26:230-245, each of which is incorporated by reference in its entirety.
  • Single domain antibodies are also known as sdAbs or nanobodies.
  • a “multispecific antibody” is an antibody that comprises two or more different antigen-binding domains that collectively specifically bind two or more different epitopes.
  • the two or more different epitopes may be epitopes on the same antigen (e.g., a single TIGIT molecule expressed by a cell) or on different antigens (e.g., different TIGIT molecules expressed by the same cell, or a TIGIT molecule and a non-TIGIT molecule).
  • a multi-specific antibody binds two different epitopes (i.e., a “bispecific antibody”).
  • a multi-specific antibody binds three different epitopes (i.e., a “trispecific antibody”).
  • a multi-specific antibody binds four different epitopes (i.e., a “quadspecific antibody”). In some aspects, a multi-specific antibody binds five different epitopes (i.e., a “quintspecific antibody”). In some aspects, a multi-specific antibody binds 6, 7, 8, or more different epitopes. Each binding specificity may be present in any suitable valency.
  • a “monospecific antibody” is an antibody that comprises one or more binding sites that specifically bind to a single epitope.
  • An example of a monospecific antibody is a naturally occurring IgG molecule which, while divalent (i.e., having two antigen-binding domains), recognizes the same epitope at each of the two antigen-binding domains.
  • the binding specificity may be present in any suitable valency.
  • a monoclonal antibody refers to an antibody from a population of substantially homogeneous antibodies.
  • a population of substantially homogeneous antibodies comprises antibodies that are substantially similar and that bind the same epitope(s), except for variants that may normally arise during production of the monoclonal antibody. Such variants are generally present in only minor amounts.
  • a monoclonal antibody is typically obtained by a process that includes the selection of a single antibody from a plurality of antibodies.
  • the selection process can be the selection of a unique clone from a plurality of clones, such as a pool of hybridoma clones, phage clones, yeast clones, bacterial clones, or other recombinant DNA clones.
  • the selected antibody can be further altered, for example, to improve affinity for the target (“affinity maturation”), to humanize the antibody, to improve its production in cell culture, and/or to reduce its immunogenicity in a subject.
  • chimeric antibody refers to an antibody in which a portion of the heavy and/or light chain is derived from a particular source or species, while the remainder of the heavy and/or light chain is derived from a different source or species.
  • “Humanized” forms of non-human antibodies are chimeric antibodies that contain minimal sequence derived from the non-human antibody.
  • a humanized antibody is generally a human antibody (recipient antibody) in which residues from one or more CDRs are replaced by residues from one or more CDRs of a non-human antibody (donor antibody).
  • the donor antibody can be any suitable non-human antibody, such as a mouse, rat, rabbit, chicken, or non-human primate antibody having a desired specificity, affinity, or biological effect.
  • selected framework region residues of the recipient antibody are replaced by the corresponding framework region residues from the donor antibody.
  • Humanized antibodies may also comprise residues that are not found in either the recipient antibody or the donor antibody. Such modifications may be made to further refine antibody function.
  • a “human antibody” is one which possesses an amino acid sequence corresponding to that of an antibody produced by a human or a human cell, or derived from a non-human source that utilizes a human antibody repertoire or human antibody-encoding sequences (e.g., obtained from human sources or designed de novo). Human antibodies specifically exclude humanized antibodies.
  • the antibody or antigen-binding protein provided with the compositions described herein targets a particular host cell type.
  • the antibody or antibody binds to a non-host cell, such as a bacterial or fungal cell.
  • the antibody or ADP is at least bispecific and binds to at least two host targets.
  • the antibody or ADC is at least bispecific and binds to at least one host target and one non-host target.
  • the antibody or ADP is monospecific or bispecific.
  • the antibody is trispecific or tetraspecific.
  • the antibody agonizes a receptor. In an embodiment, the antibody antagonizes a receptor.
  • compositions provided herein further comprise cells for delivery.
  • the cells are derived from the subject to whom they are administered.
  • the cells are derived from a source other than the subject to whom they are administered.
  • the cells are derived from a cell line.
  • the cells are derived from a human source.
  • the cells are derived from a humanized animal source.
  • the cells provided are stem cells.
  • the cells provided are fat cells (adipocytes). In some aspects, the cells provided are muscle cells, nerve cells, skin cells, or organ cells. In some aspects, the cells provided are liver cells, pancreatic cells, cardiac cells, lung cells, esophageal cells, endothelial cells, or epithelial cells.
  • the cells provided are immune cells Immune cells provided in some embodiments are T cells or B cells. In some embodiments, the cells provided are CD-8+ T cells. In some embodiments, the cells provided are CD-4+ T cells.
  • the cells provided produce a useful substance, such as insulin, collagen, or an antibody. In some embodiments, this ability is introduced via recombinant DNA.
  • compositions provided herein further comprise small molecules for delivery, wherein the small molecule is a biologically active material.
  • the small molecule can cause pharmacological activity or anther direct effect in the diagnosis, cure, mitigation, treatment or prevention of disease or can affect the structure or function of the body.
  • the gel/hydrogel/nanostructure composites of the invention can also include tissue-repairing agents, such as, a number of growth factors, including epidermal growth factor (EDF), PDGF, and nerve growth factors (NGF's).
  • the compositions may include EGF.
  • Epidermal Growth Factor (EGF) was discovered after the observation that cutaneous wounds in laboratory mice seemed to heal more rapidly when the mice were allowed to lick them. This was not simply due to some antiseptic agent in saliva (such as lysozyme).
  • EGF is identical to urogastrone and has angiogenic properties.
  • Transforming growth factor-alpha (TGF ⁇ ) is very similar, binding to the same receptor and is even more effective in stimulating epithelial cell regeneration (epithelisation).
  • hydrogels of the present invention comprising EGF/TGF may advantageously be used in the acceleration of wound healing and burns, reduction in keloid scar formation (especially for burns), skin engraftment dressings, and the treatment of chronic leg ulcers.
  • Tissue-repairing agents useful in the present invention include a number of growth factors, including epidermal growth factor (EDF), PDGF, and nerve growth factors (NGF's).
  • EDF epidermal growth factor
  • NGF's nerve growth factors
  • growth-promoting hormones will affect between one and four tissues. Many of the products developed from such proteins are targeted towards wound repairs of one kind or another, although there are other indications. Some of the most important tissue growth factors are described further below.
  • the gel/nanostructure compositions of the invention may also include one or more growth factors that may be useful in the tissue repair methods and other applications of the invention.
  • the invention contemplates include PDGF in the compositions of the invention.
  • Platelet-Derived Growth Factor PDGF
  • PDGF Platelet-Derived Growth Factor
  • It is a dimeric glycoprotein existing as AA or BB homodimers, or as the AB heterodimer.
  • PDGF is now considered to be a member of a larger family of factors.
  • this family includes the homodimeric factors vascular endothelial growth factor (VEGF) and placental growth factor (PIGF), VEGF/PIGF heterodimers, and connective tissue growth factor (CTGF), a PDGF-like factor secreted by human vascular endothelial cells and fibroblasts.
  • VEGF vascular endothelial growth factor
  • PIGF placental growth factor
  • CGF connective tissue growth factor
  • TGF ⁇ and glycoprotein hormones such as human chorionic gonadotropic hormone (hCG)
  • PDGF is now classified as a member of the cysteine-knot growth factor superfamily. All of these factors may be used in conjunction with hydrogels of the present invention.
  • PDGF is produced by platelets and released in the course of blood clotting. It is just one of the growth factors that derive from these cells. PDGF attracts fibroblasts and white blood cells to the site of the injury, as well as stimulating the growth of replacement connective tissue (mainly fibroblasts and smooth muscle cells). It stimulates cell division in various cells, including those that produce collagen, so encouraging angiogenesis. It also stimulates mitogenesis, vasoconstriction, chemotaxis, enzyme activity and calcium mobilization.
  • Blood platelet derived growth factors may be used to restore bone and soft tissue regrowth during certain treatments using the compositions of the invention and to accelerate the healing process of chronic and acute wounds. Accordingly, hydrogel/nanostructure compositions of the present invention may advantageously comprise a platelet derived growth factor cocktail.
  • Hydrogel/nanostructure compositions of the present invention may be used in gene therapy for local delivery of the PDGF gene, for example.
  • Plasmid DNA encoding PDGF is incorporated into the hydrogel matrix and granulation tissue fibroblasts, which originate in viable tissue surrounding the wound, proliferate and migrate into the matrix, acting as targets for plasmid gene transfer and expression.
  • the hydrogel/nanostructure compositions of the invention may also include VEGF to promote angiogenesis.
  • Vascular Endothelial Growth Factor (VEGF—also known as vascular permeability factor) is another vascular growth factor that is a multifunctional angiogenic cytokine. It contributes to angiogenesis (blood vessel growth) both indirectly and directly by stimulating proliferation of endothelial cells at the microvessel level, causing them to migrate and to alter their generic expression.
  • VEGF also makes theses endothelial cells hyperpermeable, causing them to release plasma proteins outside the vascular space, which causes changes in the area, contributing to angiogenesis.
  • compositions of the invention may also include FGF.
  • Fibroblast Growth Factor is actually a family of at least 19 14 18 kD peptides belonging to the heparin-binding growth factors family and are mitogenic for cultured fibroblasts and vascular endothelial cells. They are also angiogenic in vivo and this angiogenicity is enhanced by TNF. FGF's may be used in a similar manner to EGF.
  • bFGF also known as FGF-2, is involved in controlling human megakaryocytopoiesis and FGFs have been shown to be effective in stimulating endothelial cell formation, and in assisting in connective tissue repair.
  • Hydrogel/nanostructure compositions may also comprise Keratinocyte Growth Factor (KGF), also known as FGF-7, for use in wound healing and other disorders involving epithelial cell destruction.
  • KGF Keratinocyte Growth Factor
  • TGFs Transforming Growth Factors
  • TGF-alpha and TGF-beta The former is mitogenic for fibroblasts and endothelial cells, angiogenic, and promotes bone resorption.
  • Compositions also may include TGF.
  • TGF-beta is a general mediator of cell regulation, a powerful inhibitor of cell growth, and inhibits the proliferation of many cell types.
  • TGF-beta can antagonize the mitogenic effects of other peptide growth factors and can also inhibit the growth of many tumour cell lines. TGF-beta also has angiogenic effects and promotes collagen formation in fibroblasts. Indications for hydrogels of the present invention include chronic skin ulcers, such as neurotrophic foot ulcers in diabetic patients. Other areas include wound healing, bone repair and immunosuppressive diseases.
  • Hydrogel/nanostructure compositions of the present invention may be used to carry suitable cells, for example. These may be incorporated into the gel just prior to application to a wound, or other suitable area, to maximize efficacy.
  • suitable cells include autologous fibroblasts and keratinocytes, which are mainly responsible for dermis and epidermis formation. Separate gels each comprising one cell type may be applied consecutively or together, or one gel may comprise both cell types, but this is generally less preferred.
  • Hydrogel/nanostructure compositions of the present invention may usefully comprise collagen, for example.
  • collagen in this form, is unlikely to serve a useful structural function, it primarily serves as a sacrificial protein where proteolytic activity is undesirably high, thereby helping to prevent maceration of healthy tissue, for example.
  • Hydrogel/nanostructure compositions can also include certain enzymes.
  • Enzymes are used in the debridement of both acute and chronic wounds. Debridement is the removal of nonviable tissue and foreign matter from a wound and is a naturally occurring event in the wound-repair process. During the inflammatory phase, neutrophils and macrophages digest and remove “used” platelets, cellular debris, and avascular injured tissue from the wound area. However, with the accumulation of significant amounts of damaged tissue, this natural process becomes overwhelmed and insufficient. Build-up of necrotic tissue then places considerable phagocytic demand on the wound and retards wound healing. Consequently, debridement of necrotic tissue is a particular objective of topical therapy and an important component of optimal wound management.
  • Enzymes may be incorporated into hydrogels of the present invention for topical application to provide a selective method of debridement.
  • Suitable enzymes may be derived from various sources, such as krill, crab, papaya, bovine extract, and bacteria
  • suitable enzymes include collagenase, papain/urea, and a fibrinolysin and deoxyribonuclease combination.
  • Enzymes for use in the present invention generally work in one of two ways: by directly digesting the components of slough (e.g., fibrin, bacteria, leukocytes, cell debris, serous exudate, DNA); or, by dissolving the collagen “anchors” that secure the avascular tissue to the underlying wound bed.
  • slough e.g., fibrin, bacteria, leukocytes, cell debris, serous exudate, DNA
  • Hydrogels of the present invention may comprise Dakin's solution, if desired, generally to exert antimicrobial effects and odor control.
  • Dakin's solution is non-selective because of its cytotoxic properties. Dakin's solution denatures protein, rendering it more easily removed from the wound. Loosening of the slough also facilitates debridement by other methods.
  • Hydrogels comprising Dakin's solution may be changed twice daily if the goal is debridement.
  • Periwound skin protection should generally be provided with ointments, liquid skin barrier film dressings, or solid skin barrier wafers, for example.
  • the gel of the present invention may be delivered by any suitable method, such as via a syringe or bellows pack (single dose delivery systems) or a multidose system, such as a pressurized delivery system or delivery via a ‘bag in the can’ type system (such as that published in WO98/32675).
  • a bellows pack is shown in published UK design number 2082665.
  • the present invention also extends to a single dose delivery system comprising a gel according to the present invention, for the treatment of wounds.
  • the invention also extends to a pressurized delivery system comprising a gel according to the present invention, and a pressurized hydrogel according to the present invention in an aerosol container capable of forming a spray upon release of pressure therefrom.
  • Use of such delivery means allows the gel to be delivered to areas on a patient which are otherwise difficult to reach by direct application, such as on the back of a patient when the patient is lying down.
  • the hydrogel compositions of the invention may be electrically conductive for use in biomedical electrodes and other electrotherapy contexts, i.e., to attach an electrode or other electrically conductive member to the body surface.
  • the hydrogel composition may be used to attach a transcutaneous nerve stimulation electrode, an electrosurgical return electrode, or an EKG electrode to a patient's skin or mucosal tissue.
  • Suitable conductive species are ionically conductive electrolytes, particularly those that are normally used in the manufacture of conductive adhesives used for application to the skin or other body surface, and include ionizable inorganic salts, organic compounds, or combinations of both.
  • ionically conductive electrolytes include, but are not limited to, ammonium sulfate, ammonium acetate, monoethanolamine acetate, diethanolamine acetate, sodium lactate, sodium citrate, magnesium acetate, magnesium sulfate, sodium acetate, calcium chloride, magnesium chloride, calcium sulfate, lithium chloride, lithium perchlorate, sodium citrate and potassium chloride, and redox couples such as a mixture of ferric and ferrous salts such as sulfates and gluconates.
  • Preferred salts are potassium chloride, sodium chloride, magnesium sulfate, and magnesium acetate, and potassium chloride is most preferred for EKG applications.
  • any electrolyte present in the adhesive compositions of the invention it is preferable that any electrolyte present be at a concentration in the range of about 0.1 to about 15 wt. % of the hydrogel composition.
  • the procedure described in U.S. Pat. No. 5,846,558 to Nielsen et al. for fabricating biomedical electrodes may be adapted for use with the hydrogel compositions of the invention, and the disclosure of that patent is incorporated by reference with respect to manufacturing details. Other suitable fabrication procedures may be used as well, as will be appreciated by those skilled in the art.
  • the polymers of the gel/hydrogels of the invention may be covalently crosslinked.
  • crosslinking may be desired as between the polymers of the gel/hydrogel component, but also crosslinking may be desired as between the polymers of the gel/hydrogel and the nanostructure components of the composite materials of the invention.
  • the invention contemplates any suitable means for crosslinking polymers to one another, and crosslinking the gel/hydrogel polymers with the nanostructure components of the invention.
  • the gel/hydrogel polymers may be covalently crosslinked to other polymers or to the nanostructures, either intramolecularly or intermolecularly or through covalent bonds.
  • crosslinks may be formed using any suitable means, including using heat, radiation, or a chemical curing (crosslinking) agent.
  • the degree of crosslinking should be sufficient to eliminate or at least minimize cold flow under compression.
  • Crosslinking also includes the use of a third molecule, a “cross-linker” utilized in the cross-linking process.
  • Cross-linkers or “Cross-linking agents” may be suitably chosen from the group of poly(ethylene glycol) PEG, e.g. thiolated poly(ethylene glycol), poly(ethylene glycol) diacrylate (PEGDA), or derivatives thereof.
  • a free radical polymerization initiator is used, and can be any of the known free radical-generating initiators conventionally used in vinyl polymerization.
  • Preferred initiators are organic peroxides and azo compounds, generally used in an amount from about 0.01 wt. % to 15 wt. %, preferably 0.05 wt. % to 10 wt. %, more preferably from about 0.1 wt. % to about 5% and most preferably from about 0.5 wt. % to about 4 wt. % of the polymerizable material.
  • Suitable organic peroxides include dialkyl peroxides such as t-butyl peroxide and 2,2bis(t-butylperoxy)propane, diacyl peroxides such as benzoyl peroxide and acetyl peroxide, peresters such as t-butyl perbenzoate and t-butyl per-2-ethylhexanoate, perdicarbonates such as dicetyl peroxy dicarbonate and dicyclohexyl peroxy dicarbonate, ketone peroxides such as cyclohexanone peroxide and methylethylketone peroxide, and hydroperoxides such as cumene hydroperoxide and tert-butyl hydroperoxide.
  • dialkyl peroxides such as t-butyl peroxide and 2,2bis(t-butylperoxy)propane
  • diacyl peroxides such as benzoyl peroxide and acetyl
  • Suitable azo compounds include azo bis (isobutyronitrile) and azo bis (2,4-dimethylvaleronitrile).
  • the temperature for thermally crosslinking will depend on the actual components and may be readily deduced by one of ordinary skill in the art, but typically ranges from about 80° C. to about 200° C.
  • Crosslinking may also be accomplished with radiation, typically in the presence of a photoinitiator.
  • the radiation may be ultraviolet, alpha, beta, gamma, electron beam, and x-ray radiation, although ultraviolet radiation is preferred.
  • Useful photosensitizers are triplet sensitizers of the “hydrogen abstraction” type, and include benzophenone and substituted benzophenone and acetophenones such as benzyl dimethyl ketal, 4-acryloxybenzophenone (ABP), 1-hydroxy-cyclohexyl phenyl ketone, 2,2-diethoxyacetophenone and 2,2-dimethoxy-2-phenylaceto-phenone, substituted alpha-ketols such as 2-methyl-2-hydroxypropiophenone, benzoin ethers such as benzoin methyl ether and benzoin isopropyl ether, substituted benzoin ethers such as anisoin methyl ether, aromatic sulfonyl chlorides such as 2-naphthalen
  • photosensitizers of the hydrogen abstraction type higher intensity UV exposure may be necessary to achieve sufficient crosslinking.
  • Such exposure can be provided by a mercury lamp processor such as those available from PPG, Fusion, Xenon, and others.
  • Crosslinking may also be induced by irradiating with gamma radiation or an electron beam. Appropriate irradiation parameters, i.e., the type and dose of radiation used to effect crosslinking, will be apparent to those skilled in the art.
  • Suitable chemical curing agents also referred to as chemical cross-linking “promoters,” include, without limitation, polymercaptans such as 2,2-dimercapto diethylether, dipentaerythritol hexa(3-mercaptopropionate), ethylene bis(3-mercaptoacetate), pentaerythritol tetra(3-mercaptopropionate), pentaerythritol tetrathioglycolate, polyethylene glycol dimercaptoacetate, polyethylene glycol di(3-mercaptopropionate), trimethylolethane tri(3-mercaptopropionate), trimethylolethane trithioglycolate, trimethylolpropane tri(3-mercaptopropionate), trimethylolpropane trithioglycolate, dithioethane, di- or trithiopropane and 1,6-hexane dithiol.
  • the crosslinking promoter is added to
  • the polymers and/or nanostructures may also be crosslinked prior to admixture with the complementary oligomer.
  • it may be preferred to synthesize the polymer in crosslinked form, by admixing a monomeric precursor to the polymer with multifunctional comonomer and copolymerizing.
  • Examples of monomeric precursors and corresponding polymeric products are as follows: N-vinyl amide precursors for a poly(N-vinyl amide) product; N-alkylacrylamides for a poly(N-alkylacrylamide) product; acrylic acid for a polyacrylic acid product; methacrylic acid for a polymethacrylic acid product; acrylonitrile for a poly(acrylonitrile) product; and N-vinyl pyrrolidone (NVP) for a poly(vinylpyrrolidone) (PVP) product.
  • Polymerization may be carried out in bulk, in suspension, in solution, or in an emulsion.
  • Solution polymerization is preferred, and polar organic solvents such as ethyl acetate and lower alkanols (e.g., ethanol, isopropyl alcohol, etc.) are particularly preferred.
  • polar organic solvents such as ethyl acetate and lower alkanols (e.g., ethanol, isopropyl alcohol, etc.) are particularly preferred.
  • synthesis will typically take place via a free radical polymerization process in the presence of a free radical initiator as described above.
  • the multifunctional comonomer include, for example, bisacrylamide, acrylic or methacrylic esters of diols such as butanediol and hexanediol (1,6-hexane diol diacrylate is preferred), other acrylates such as pentaerythritol tetraacrylate, and 1,2-ethylene glycol diacrylate, and 1,12-dodecanediol diacrylate.
  • multifunctional crosslinking monomers include oligomeric and polymeric multifunctional (meth)acrylates, e.g., poly(ethylene oxide) diacrylate or poly(ethylene oxide) dimethacrylate; polyvinylic crosslinking agents such as substituted and unsubstituted divinylbenzene; and difunctional urethane acrylates such as EBECRYL 270 and EBECRYL 230 (1500 weight average molecular weight and 5000 weight average molecular weight acrylated urethanes, respectively—both available from UCB of Smyrna, Ga.), and combinations thereof.
  • oligomeric and polymeric multifunctional (meth)acrylates e.g., poly(ethylene oxide) diacrylate or poly(ethylene oxide) dimethacrylate
  • polyvinylic crosslinking agents such as substituted and unsubstituted divinylbenzene
  • difunctional urethane acrylates such as EBECRYL 270 and EBECRYL 230 (1500 weight average mole
  • the amount used will preferably be such that the weight ratio of crosslinking agent to hydrophilic polymer is in the range of about 1:100 to 1:5.
  • chemical crosslinking is combined with radiation curing.
  • the nanostructure components of the invention may be in any suitable form including fibers, filaments, mesh sections, branched filaments or networks, sheets, or shaped particles.
  • the nanostructures may also comprise any suitable chemical functional groups to facilitate the covalent or noncovalent crosslinking between the nanostructures and the polymers of the hydrogels of the invention. Method, techniques, and materials are well known in the art for making and functionalizing nanostructures.
  • microfabrication methods are used to make the nanostructures of the invention.
  • the disclosed devices can be assembled and/or manufactured using any suitable microfabrication technique. Such methods and techniques are widely known in the art.
  • Microfabrication processes that can be used in making the nanostructures disclosed herein include lithography; etching techniques, such as lasers, plasma etching, photolithography, or chemical etching such as wet chemical, dry, and photoresist removal; or by solid free form techniques, including three-dimensional printing (3DP), stereolithography (SLA), selective laser sintering (SLS), ballistic particle manufacturing (BPM) and fusion deposition modeling (FDM); by micromachining; thermal oxidation of silicon; electroplating and electroless plating; diffusion processes, such as boron, phosphorus, arsenic, and antimony diffusion; ion implantation; film deposition, such as evaporation (filament, electron beam, flash, and shadowing and step coverage), sputtering, chemical vapor deposition (CVD), epitaxy (vapor phase, liquid phase, and molecular beam), electroplating, screen printing, lamination or by combinations thereof.
  • etching techniques such as lasers, plasma etching, photolithography, or
  • MEMS Micro Electro Mechanical Systems
  • More recently developed methods include “soft lithography” (Whitesides et al, Angew chem. Int ed, 37; 550-575, (1998)) and microfluidic tectonics (U.S. Pat. No. 6,488,872, Beebe et al., Nature; 404:588-59 (2000)).
  • Reviews and other discussions of polymer microdevice fabrication include Madou, M. J. Fundamentals of Microfabrication: The Science of Miniaturization; 2nd ed.; CRC Press: Boca Raton, 1997; Becker, H., and Locascio, L. E.
  • the nanostructures of the invention may also be fabricated by electrostatic spinning (also referred to as electrospinning).
  • electrospinning also referred to as electrospinning.
  • the technique of electrospinning of liquids and/or solutions capable of forming fibers is well known and has been described in a number of patents, such as, for example, U.S. Pat. Nos. 4,043,331 and 5,522,879.
  • the process of electrospinning generally involves the introduction of a liquid into an electric field, so that the liquid is caused to produce fibers. These fibers are generally drawn to a conductor at an attractive electrical potential for collection. During the conversion of the liquid into fibers, the fibers harden and/or dry.
  • This hardening and/or drying may be caused by cooling of the liquid, i.e., where the liquid is normally a solid at room temperature; by evaporation of a solvent, e.g., by dehydration (physically induced hardening); or by a curing mechanism (chemically induced hardening).
  • Nanofibers ranging from 50 nm to 5 micrometers in diameter can be electrospun into a nonwoven or an aligned nanofiber mesh. Due to the small fiber diameters, electrospun textiles inherently possess a very high surface area and a small pore size. These properties make electrospun fabrics potential candidates for a number of applications including: membranes, tissue scaffolding, and other biomedical applications.
  • Electrostatically spun fibers can be produced having very thin diameters. Parameters that influence the diameter, consistency, and uniformity of the electrospun fibers include the polymeric material and cross-linker concentration (loading) in the fiber-forming combination, the applied voltage, and needle collector distance.
  • a nanofiber has a diameter ranging from about 1 nm to about 100 .mm. In other embodiments, the nanofiber has a diameter in a range of about 1 nm to about 1000 nm. Further, the nanofiber may have an aspect ratio in a range of at least about 10 to about at least 100. It will be appreciated that, because of the very small diameter of the fibers, the fibers have a high surface area per unit of mass. This high surface area to mass ratio permits fiber-forming solutions or liquids to be transformed from liquid or solvated fiber-forming materials to solid nanofibers in fractions of a second.
  • the polymeric material used to form the nanofibers/nanostructures of the invention may be selected from any fiber forming material which is compatible with the cross-linking agents.
  • the fiber-forming polymeric material may be hydrophilic, hydrophobic or amphiphilic. Additionally, the fiber-forming polymeric material may be a thermally responsive polymeric material.
  • Synthetic or natural, biodegradable or non-biodegradable polymers may form the nanofibers/nanostructures of the invention.
  • a “synthetic polymer” refers to a polymer that is synthetically prepared and that includes non-naturally occurring monomeric units.
  • a synthetic polymer can include non-natural monomeric units such as acrylate or acrylamide units.
  • Synthetic polymers are typically formed by traditional polymerization reactions, such as addition, condensation, or free-radical polymerizations.
  • Synthetic polymers can also include those having natural monomeric units, such as naturally-occurring peptide, nucleotide, and saccharide monomeric units in combination with non-natural monomeric units (for example synthetic peptide, nucleotide, and saccharide derivatives). These types of synthetic polymers can be produced by standard synthetic techniques, such as by solid phase synthesis, or recombinantly, when allowed.
  • a “natural polymer” refers to a polymer that is either naturally, recombinantly, or synthetically prepared and that consists of naturally occurring monomeric units in the polymeric backbone.
  • the natural polymer may be modified, processed, derivatized, or otherwise treated to change the chemical and/or physical properties of the natural polymer.
  • the term “natural polymer” will be modified to reflect the change to the natural polymer (for example, a “derivatized natural polymer”, or a “deglycosylated natural polymer”).
  • Nanofiber materials may include both addition polymer and condensation polymer materials such as polyolefin, polyacetal, polyamide, polyester, cellulose ether and ester, polyalkylene sulfide, polyarylene oxide, polysulfone, modified polysulfone polymers and mixtures thereof.
  • addition polymer and condensation polymer materials such as polyolefin, polyacetal, polyamide, polyester, cellulose ether and ester, polyalkylene sulfide, polyarylene oxide, polysulfone, modified polysulfone polymers and mixtures thereof.
  • Exemplary materials within these generic classes include polyethylene, poly( ⁇ -caprolactone), poly(lactate), poly(glycolate), polypropylene, poly(vinylchloride), polymethylmethacrylate (and other acrylic resins), polystyrene, and copolymers thereof (including ABA type block copolymers), poly(vinylidene fluoride), poly(vinylidene chloride), polyvinyl alcohol in various degrees of hydrolysis (87% to 99.5%) in crosslinked and non-crosslinked forms.
  • Exemplary addition polymers tend to be glassy (a Tg greater than room temperature). This is the case for polyvinylchloride and polymethylmethacrylate, polystyrene polymer compositions, or alloys or low in crystallinity for polyvinylidene fluoride and polyvinyl alcohol materials.
  • the nanofiber/nanostructure materials are polyamide condensation polymers.
  • the polyamide condensation polymer is a nylon polymer.
  • nylon is a generic name for all long chain synthetic polyamides.
  • Another nylon can be made by the polycondensation of epsilon caprolactam in the presence of a small amount of water. This reaction forms a nylon-6 (made from a cyclic lactam—also known as epsilon-aminocaproic acid) that is a linear polyamide.
  • nylon copolymers are also contemplated.
  • Block copolymers can also be used as nanofiber materials.
  • a solvent system can be chosen such that both blocks are soluble in the solvent.
  • One example is an ABA (styrene-EP-styrene) or AB (styrene-EP) polymer in methylene chloride solvent.
  • block copolymers examples include a Kraton-type of AB and ABA block polymers including styrene/butadiene and styrene/hydrogenated butadiene(ethylene propylene), a Pebax-type of epsilon-caprolactam/ethylene oxide and a Sympatex-type of polyester/ethylene oxide and polyurethanes of ethylene oxide and isocyanates.
  • Addition polymers such as polyvinylidene fluoride, syndiotactic polystyrene, copolymers of vinylidene fluoride and hexafluoropropylene, polyvinyl alcohol, polyvinyl acetate, amorphous addition polymers, such as poly(acrylonitrile) and its copolymers with acrylic acid and methacrylates, polystyrene, poly(vinyl chloride) and its various copolymers, poly(methyl methacrylate) and its various copolymers, can be solution spun with relative ease because they are soluble at low pressures and temperatures. Highly crystalline polymer like polyethylene and polypropylene generally require higher temperature and high-pressure solvents if they are to be solution spun.
  • Nanofibers can also be formed from polymeric compositions comprising two or more polymeric materials in polymer admixture, alloy format, or in a crosslinked chemically bonded structure.
  • Two related polymer materials can be blended to provide the nanofiber with beneficial properties.
  • a high molecular weight polyvinylchloride can be blended with a low molecular weight polyvinylchloride.
  • a high molecular weight nylon material can be blended with a low molecular weight nylon material.
  • differing species of a general polymeric genus can be blended.
  • a high molecular weight styrene material can be blended with a low molecular weight, high impact polystyrene.
  • a Nylon-6 material can be blended with a nylon copolymer such as a Nylon-6; 6,6; 6,10 copolymer. Further, a polyvinyl alcohol having a low degree of hydrolysis such as a 87% hydrolyzed polyvinyl alcohol can be blended with a fully or super hydrolyzed polyvinyl alcohol having a degree of hydrolysis between 98 and 99.9% and higher. All of these materials in admixture can be crosslinked using appropriate crosslinking mechanisms. Nylons can be crosslinked using crosslinking agents that are reactive with the nitrogen atom in the amide linkage.
  • Polyvinyl alcohol materials can be crosslinked using hydroxyl reactive materials such as monoaldehydes, such as formaldehyde, ureas, melamine-formaldehyde resin and its analogues, boric acids, and other inorganic compounds, dialdehydes, diacids, urethanes, epoxies, and other known crosslinking agents.
  • Crosslinking reagent reacts and forms covalent bonds between polymer chains to substantially improve molecular weight, chemical resistance, overall strength and resistance to mechanical degradation.
  • Biodegradable polymers can also be used in the preparation of the nanostructures of the invention.
  • classes of synthetic polymers that have been studied as biodegradable materials include polyesters, polyamides, polyurethanes, polyorthoesters, polycaprolactone (PCL), polyiminocarbonates, aliphatic carbonates, polyphosphazenes, polyanhydrides, and copolymers thereof.
  • biodegradable materials that can be used in connection with, for example, implantable medical devices include polylactide, polyglycolide, polydioxanone, poly(lactide-co-glycolide), poly(glycolide-co-polydioxanone), polyanhydrides, poly(glycolide-co-trimethylene carbonate), and poly(glycolide-co-caprolactone). Blends of these polymers with other biodegradable polymers can also be used.
  • the nanofibers are non-biodegradable polymers.
  • Non-biodegradable refers to polymers that are generally not able to be non-enzymatically, hydrolytically or enzymatically degraded.
  • the non-biodegradable polymer is resistant to degradation that may be caused by proteases.
  • Non-biodegradable polymers may include either natural or synthetic polymers.
  • cross-linking agents within the composition forming the nanofiber, allows the nanofiber to be compatible with a wide range of support surfaces.
  • the cross-linking agents can be used alone or in combination with other materials to provide a desired surface characteristic.
  • Suitable cross-linking agents include either monomeric (small molecule materials) or polymeric materials having at least two latent reactive activatable groups that are capable of forming covalent bonds with other materials when subjected to a source of energy such as radiation, electrical or thermal energy.
  • latent reactive activatable groups are chemical entities that respond to specific applied external energy or stimuli to generate active species with resultant covalent bonding to an adjacent chemical structure.
  • Latent reactive groups are those groups that retain their covalent bonds under storage conditions but that form covalent bonds with other molecules upon activation by an external energy source.
  • latent reactive groups form active species such as free radicals. These free radicals may include nitrenes, carbine or excited states of ketones upon absorption of externally applied electric, electrochemical or thermal energy.
  • Various examples of known or commercially available latent reactive groups are reported in U.S. Pat. Nos. 4,973,493; 5,258,041; 5,563,056; 5,637,460; or 6,278,018.
  • the commercially available multifunctional photocrosslinkers based on trichloromethyl triazine available either from Aldrich Chemicals, Produits Chimiques Auxiliaires et de Syntheses, (Longjumeau, France), Shin-Nakamara Chemical, Midori Chemicals Co., Ltd. or Panchim S. A. (France) can be used.
  • the eight compounds include 2,4,6-tris(trichloromethyl)-1,3,5 triazine, 2-(methyl)-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-(4-methoxynaphthyl)-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-(4-ethoxynaphthyl)-4,6-bis(trichloromethyl)-1,3,5-triazine, 4-(4-carboxylphenyl)-2,6-bis(trichloromethyl)-1,3,5-triazine, 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-(1-ethen-2-2′-furyl)-4,6-bis(trichloromethyl)-1,3,5-triazine and 2-(4-methoxystyryl)-4,6-bis(trichloromethyl)
  • the gel/hydrogel/nanostructure compositions disclosed herein can be used advantageously in numerous tissue repair situations, as well as in other applications, such as providing coatings on catheters and other surgical devices and implants.
  • the gel/hydrogel/nanostructure compositions of the invention can also be used to deliver active agents described herein, such as antibiotics, growth factors, and immunosuppressive agents.
  • the invention provides a method for healing a soft tissue defect comprising applying a composite material to a soft tissue defect, wherein the composite material includes a gel and a nanostructure disposed within the gel.
  • advantageous properties of the hydrogels/nanostructure compositions described herein include the ability to: 1) provide easy characterization and quality control; 2) integrate with existing tissue matrices; 3) directly incorporate into newly formed matrices; 4) directly include cells and bioactive factors; 5) maintain biocompatibility; 6) control bioresorption; 7) cast easily into complicated anatomical shapes due to greater structural rigidity owing to the nanostructures; and 8) exhibit the mechanical properties of native tissues such as articular cartilage.
  • the hydrogel/nanostructure composite compositions of the invention can be used to repair cartilage tissue.
  • Current biologically-based surgical procedures for cartilage repair include autologous chondrocyte implantation, drilling, abrasion chondroplasty, microfracture, and mosaic arthroplasty. All these procedures treat only focal articular cartilage injuries, and not cartilage denuded joint surfaces such as seen in severe osteoarthritis and rheumatoid arthritis. Also, they use either cartilage tissue plugs or expanded chondrocytes harvested from the patient to fill cartilage defects.
  • the present hydrogel/nanostructure compositions can be prepared having widely varying properties that are suitable for any number of synthetic tissue implantation or augmentation, as well as other clinical applications.
  • the present materials can be used to repair cartilage defects produced as a result of either injury or disease. Defects due to injury that can be so repaired can be sports- or accident-related, and may involve only the superficial cartilage layer, or may include the underlying subchondral bone. Defects due to disease which can be repaired using the compositions described herein include those resulting from osteoarthritis and rheumatoid arthritis. Whether from injury or disease, such defects may be in either mature or growth plate cartilage. Formulations for hydrogels for synthetic growth plate cartilage may require the inclusion of unsubstituted scaffold material to allow for controlled bioresorption of the biomaterial during growth.
  • hydrogel/nanostructure compositions described herein can be useful is the repair, reconstruction or augmentation of cartilaginous as well as soft tissues of the head and neck.
  • the availability of biomaterials for soft tissue augmentation and head and neck reconstruction has remained a fundamental challenge in the field of plastic and reconstructive surgery.
  • Significant research and investment has been undertaken for the development of a material with appropriate biological compatibility and life span.
  • the outcomes of this research have not been promising.
  • When placed in immunocompetent animals the structural integrity of currently proposed materials has been shown to fail as the framework is absorbed.
  • conventional synthetic materials offer excellent lifespan, they present certain unavoidable pitfalls. For example, silicones have been fraught with concerns of safety and long-term immune related effects.
  • Synthetic polymers PTFE (gortex) and silastic offer less tissue reactivity but do not offer tissue integration and can represent long term risks of foreign body infections and extrusion.
  • the materials described in this application will be useful to prepare a synthetic soft-tissue scaffold material for the augmentation or repair of soft-tissue defects of the head and neck.
  • the hydrogel/nanostructure compositions which are non-inflammatory, non-immunogenic, and which can be prepared having the appropriate degree of viscoelasticity (see description herein), could be used as an effective implantable scaffold material.
  • the present hydrogel/nanostructure compositions can be used, for example, as a novel, biocompatible and biocompliant materials to prepare cartilage implants which are frequently used in reconstructive procedures of the head and neck to repair cartilaginous or bony defects secondary to trauma or congenital abnormalities.
  • Applications specific to the ear include otoplasty and auricular reconstruction, which are often undertaken to repair cartilaginous defects due to trauma, neoplasm (i.e., squamous cell carcinoma, basal cell carcinoma, and melanoma), and congenital defects such as microtia.
  • Applications specific to the nose include cosmetic and reconstructive procedures of the nose and nasal septum.
  • Dorsal hump augmentation, tip, shield and spreader grafts are frequently used in cosmetic rhinoplasty.
  • Nasal reconstruction following trauma, neoplasm, autoimmune diseases such as Wegeners granulomatosis, or congenital defects require cartilage for repair. Septal perforations are difficult to manage and often fail treatment.
  • Cartilage grafts would be ideal for these applications, as autologous or donor cartilage is often unavailable.
  • Applications specific to the throat include laryngotracheal reconstruction, which in children usually requires harvesting costal cartilage, which is not without morbidity. Auricular and septal cartilage is often inadequate for this application.
  • Synthetic cartilaginous materials prepared from hydrogels disclosed herein can be synthesized to suit each of the foregoing applications, based on tuning parameters of hydrogel synthesis such as reagent concentration, substitution and cross-linking rates.
  • Laryngotracheal reconstruction is usually performed for airway narrowing due to subglottic or tracheal stenosis.
  • the etiology may be traumatic (i.e., intubation trauma, or tracheotomy) or idiopathic.
  • Other possibilities include chin and cheek augmentation, and use in ectropion repair of the lower eyelid, in addition to numerous craniofacial applications. It should be noted that these applications may not need cartilage with the exacting mechanical properties of articular cartilage. Inclusion of a cell population or bioactive agents may also be desirable.
  • hydrogel/nanostructure compositions described herein also can be used for repair and narrowing of the nasal cavity, normally following overly aggressive surgical resection, to prevent the chronic pooling of fluid in the nasal passages that leads to infection and encrustation.
  • Another promising application is in laryngotracheal reconstruction in both children and adults, as a result of laryngotracheal injury due for example to intubation during a surgical procedure such as cardiovascular surgery.
  • Hydrogel/nanostructure compositions as herein described also can be used to provide cricoid ring replacements to protect the carotid artery following neck resection for cancer—the composition of the invention can be placed between the carotid artery and the skin as a protective barrier for the carotid artery against loss of the skin barrier.
  • a protective coating during neuronal repopulation of a resected nerve often fibrous tissue forms faster than the neuronal repopulation preventing its eventual formation. Placement of the nerve ends within a hydrogel/nanostructure composition of the invention pre-cast tube could exclude fibrous tissue formation from the site of repopulation.
  • the hydrogel/nanostructure compositions of the invention can also be used for repair of soft tissue defects of any internal or external organs.
  • the materials of the invention can be used to for chin and cheek augmentation, and use in ectropion repair of the lower eyelid, in addition to numerous craniofacial applications.
  • For cosmetic and reconstructive purposes in sites other than the head and neck for example use as breast implants for breast augmentation, as a wound sealant, for example to fill the void left after removal of lymph nodes (i.e. due to cancer) in the breast or neck, to seal the lymphatics and abate uncontrolled fluid drainage into the resection site that may lead to infection and other complications.
  • hydrogel/nanostructure compositions described herein can be used in other tissue engineering applications to produce synthetic orthopaedic tissues, including, but not limited to, bone, tendon, ligament, meniscus and intervertebral disc, using similar strategies and methodologies as described above for the synthesis of artificial forms of cartilage.
  • the hydrogel/nanostructure compositions also can be used to make synthetic non-orthopaedic tissues including but not limited to vocal cord, vitreous, heart valves, liver, pancreas and kidney, using similar strategies and methodologies as described above for the synthesis of artificial forms of cartilage.
  • hydrogel/nanostructure compositions disclosed herein can be used in gastrointestinal applications where it is necessary to treat or prevent the formation of scar tissue or strictures in abdominal or gastrointestinal organs.
  • hydrogels products at various stages of clinical and FDA approval, which generally are termed “hydrogels,” that are designed or intended to be useful in the treatment and prevention of scarring and/or stricture formation.
  • the materials of the present invention are superior to other known hydrogels in that the ones disclosed here can include a nanostructure which can provide support, shape, and strength to hydrogel materials.
  • the hydrogel/nanostructure compositions disclosed herein can be used in similar applications as the already known hydrogels are used or intended to be used, including the following: for treatment of strictures or scarring of the gastrointestinal tract.
  • the treatment involves injection of the hydrogel material at the site of an anticipated stricture to prevent scarring, or at a site of existing stricture after therapy to enlarge the narrowed GI tract to prevent the stricture from reoccurring.
  • the materials of the invention can also be used for the treatment of esophageal strictures.
  • Esophageal strictures are a common complication of gastroesophageal reflux disease (GERD).
  • GERD gastroesophageal reflux disease
  • GERD is caused by acid, bile and other injurious gastric contents refluxing into the esophagus and injuring the esophageal lining cells.
  • Approximately 7-23% of GERD patients develop an esophageal stricture, or fibrous scarring of the esophagus.
  • Esophageal scarring also can be caused by ablative therapies used to treat Barrett's esophagus.
  • ablative therapies The major complication of such ablative therapies is that the ablative injury extends too deeply into the esophageal wall and results in an esophageal scar or stricture. Esophageal strictures prevent normal swallowing and are a major cause of patient morbidity.
  • the materials described herein may be used to treat or prevent esophageal strictures resulting from GERD, Barrett's esophagus, and esophageal ablative therapies.
  • the composite materials of the invention may also be used for treatment of Crohn's disease. Crohn's disease causes strictures or scars that block off or narrow the lumen of the bowel, preventing normal bowel function.
  • the present materials may be useful to treat or prevent such strictures.
  • the composite materials can also be used in methods for treating primary sclerosing cholangitis (PSC).
  • PSC is a rare disease of the bile ducts of the liver.
  • the bile ducts form a branching network within the liver and exit the liver via two main branches that are combined into the common bile duct which drains the liver and gallbladder of bile into the duodenum.
  • the bile ducts are very narrow in diameter, measuring only up to 2 mm normally at their largest most distal portions, and yet they must normally drain liters of bile every day from the liver into the duodenum.
  • PSC is a scarring or structuring disease of the bile ducts within the liver and in the extrahepatic bile ducts described above that connect the liver to the small intestine.
  • the bile duct strictures of PSC may be treated or prevented with the present hydrogel/nanostructure compositions.
  • the composite materials of the invention can also be used to treat chronic pancreatitis.
  • Chronic pancreatitis is a chronic inflammatory disease of the pancreas that may be complicated by scars or strictures of the pancreatic ducts. These strictures block the drainage of pancreatic juice, which normally must exit the pancreas through a system of ducts or drainage conduits into the small intestine.
  • the pancreatic juice contains many digestive enzymes and other elements important to normal digestion and nutrient absorption. Blockage or narrowing of the pancreatic ducts by chronic pancreatitis can results in severe complications in which the pancreas autodigests and forms life-threatening abdominal infections and or abscesses.
  • the pancreatic strictures of chronic pancreatitis may be treated or prevented with the present hydrogels.
  • compositions may also be used for treatment of gallstone-induced bile duct and pancreatic duct strictures.
  • Gallstones are a very common disorder, a principal complication of which is the formation of bile duct and pancreatic duct strictures, which may be treated or prevented with the hydrogels.
  • ischemic bowel disease The intestines are prone to the formation of scars or strictures when their blood supply is compromised. Compromised blood flow is called ischemia, and can be caused by many pathologies, including cardiovascular disease, atherosclerosis, hypotension, hypovolemia, renal or hepatic disease-induced hypoalbuminemia, vasculitis, drug-induced disease, and many others. The end stage result of all of these etiologies can result in intestinal strictures that block off the bowel and prevent its normal function.
  • the present hydrogel/nanostructure composites may be used to treat or prevent ischemic bowel strictures.
  • hydrogel/nanostructure composites disclosed here can be used to provide a coating for non-biological structures or devices to be used in surgery or otherwise for in vivo implantation, such as surgical instruments, or ceramic or metal prostheses. Such a coating would provide a barrier between the non-biologic device material and living tissue.
  • hydrogels as a barrier for non-biologic devices includes, but is not limited to: 1) prevention of absorption of macromolecules and/or cells on the surfaces of non-biologic devices, which can lead to protein fouling or thrombosis at the device surface; 2) presentation of a non-toxic, non-inflammatory, non-immunogenic, biologically compatible surface for devices made from otherwise non-biologically compatible materials; 3) compatibility with device function such as diffusion of glucose for a glucose sensor, transmission of mechanical force for a pressure sensor, or endothelization of a vascular graft or stent; 4) enhancement of device function, such as providing a charge barrier to an existing size barrier in a MEMS based artificial nephron; 5) incorporation into non-biologic devices of a viable cell population entrapped within an aqueous, physiologically compatible environment; and 6) inclusion of drugs or bioactive factors such as growth factors, anti-viral agents, antibiotics, or adhesion molecules designed to encourage vascularization, epithelization or
  • the hydrogel/nanostructure composites of the present invention may be used to provide a non-allergenic coating for a variety of implantable devices including an implantable glucose sensor for management of diabetes.
  • the hydrogel/nanostructure composites may be used to provide: a charge barrier for the development of MEMS-based artificial nephrons; an aqueous, physiologically compatible environment in which embedded kidney cells such as podocytes can be incorporated into a MEMS-based artificial nephron design; and a coating for implantable MEMS devices designed for a variety of purposes including, but not limited to, drug delivery, mechanical sensing, and as a bio-detection system.
  • the disclosed hydrogel/nanostructure composites and particularly a hyaluronan-based hydrogel, also may be covalently attached to silicon-based devices, e.g. through first covalent attachment of the primary amine of tyramine to the silicon surface to provide a hydroxyphenyl coated surface chemistry. This may use the same chemistry used to bind DNA that has been modified with a free amine to silicon surfaces.
  • the HA-based hydrogel then is covalently coupled to the hydroxyphenyl coated surface by the same peroxidase driven chemistry used in its preferred cross-linking mode described above.
  • the hydrogel/nanostructure composites also can be used for coating non-biologic cardiovascular devices such as catheters, stents and vascular grafts. These would include devices made from materials conventionally not used because of their biological incompatibility, but which have superior design characteristics to those devices currently in use. Bioactive factors could be incorporated into the hydrogels to promote endothelization or epithelization of the hydrogel, and thus of the implanted device.
  • hydrogel/nanostructure composites of the invention can be used for any application generally used for known hydrogels, and in particular, are useful for the repair and/or regeneration of soft tissue anywhere in the body.
  • An in situ-forming composite comprising 5 mg/mL of thiolated HA (HA-SH), 10 mg/mL of polycaprolactone (PCL) fibers and the concentration of PEGDA set to match the thiol concentration 1:1 with the combined acrylate and maleimide concentrations (5 mg/mL).
  • the components were mixed together to react approximately 30 minutes before surgery in order to begin gelation, with the bulk of the gelation being completed in situ.
  • the upward arrows indicate the injection site of the gel containing HA-SH and PEGDA; while the downward arrow indicates injection site of an alternative composition containing HA-Ac and PEGSH.
  • HA acrylate (HA-Ac) group was more similar to the HA commercial negative control group, showing little encapsulation at the host-implant interface.
  • a 2-arm PEGSH crosslinker was used at a 1:1 stoichiometry of thiol to acrylate+maleimide.
  • a slightly higher initial concentration of 7 mg/mL of HA-Ac was used.
  • the fiber component was kept at 8-10 mg/mL and set the 2-arm PEGSH to have the 1:1 stoichiometry, that with the 5 k PEGSH equated to 6.9 mg/mL.
  • the 3.4 kDa and 8 kDa molecular weights of PEGSH samples were also tested, but they were weaker gels at the same stoichiometry, the 5 kDa MW was selected as the in situ gelling formulation.
  • Magnetic resonance imaging (MRI) was used to evaluate two variants of this formulation (a softer formulation based on 5.5 mg/mL HA-Ac, and a stiffer formulation based upon 7.5 mg/mL; FIG. 1D , Table 2). As seen in the Figure, little post-procedural swelling was observed compared to commercial Juvéderm® controls. The two composites tested were formulated at both ends of the stiffness regime of interest (Table 1). These formulations are similar in stiffness to the two tested variations of Juvéderma Ultra XC® and Voluma®, demonstrating the tunability of the composite disclosed herein.
  • volume retention for the composites compared to commercial controls was also assessed by MRI quantification, showing the decreased inflammation of the composites of the invention compared to the commercial control.
  • a gel comprising a pre-reacted, beaded formulation, wherein the formulation (7 mg/mL HA-Ac, 8 to 10 mg/mL of fibers with maleimide, and 6.9 m/mL of PEGSH) is fully reacted in bulk at 37° C.
  • the labile functional groups did not need to be protected, and the need for extensive mixing and curing by the end-user was removed.
  • FIG. 2 Optical microscopy images of the beaded composite are shown in FIG. 2 .
  • FIG. 2A shows the composite after being particularized into 250- ⁇ m diameter beads
  • FIG. 2B shows the composite after being further lyophilized and rehydrated, illustrating that the composite retains its original appearance
  • FIG. 2C is a 10 ⁇ image depicting nanofiber and hydrogel components of the beaded formulation
  • FIG. 2D is an optical microscopy image of the beaded formulation in a non-diluted state.
  • the beads pictured in FIG. 2 are diluted at 100 ⁇ to make visualization of the beads possible.
  • the resultant gel looks macroscopically identical to the pre-beaded state where individual beads are not discernable ( FIG. 2D ).
  • This clarification is important for the proposed mechanism of action.
  • the infiltrate cells from the host interact with the composite material in a similar manner to native extracellular matrix (ECM).
  • ECM extracellular matrix
  • the lyophilized beads can then be rehydrated within seconds and have a consistent gel property with a long working time for the end user. Bead sizes, lyophilization processes, and lyophilization formulations have been assessed to best maintain consistency to initial properties after being broken up into beads, lyophilized, then rehydrated.
  • the lyophilization formulation was an important variable, as formulations dried in PBS had much larger changes to its storage modulus, indicating changes on the microstructural level.
  • the primary drying phase required a shelf temperature maintained at ⁇ 30° C. or under in order to keep the beads as individual particles—higher lyophilization temperatures resulted in a solid plug of material that could no longer be aspirated into a syringe.
  • the non-effect of beading and lyophilization on the storage modulus for the composites described above is depicted in FIG. 2E .
  • FIG. 2G Diameters of composite beads were measured along the longest axis of the particles under a confocal microscope image. The analysis were performed counting 51 particles. Histogram of the particles ( FIG. 2G ) gives the average bead size as 209.41 ⁇ 62.27 ⁇ m.
  • FIG. 2H demonstrates confocal microscope images of beads of size ⁇ 75 ⁇ m, ⁇ 150 ⁇ m and ⁇ 200 ⁇ m by measuring the longest axis within the particle.
  • different mesh size sieves used to process the bulk composite can yield to different histograms for the bead sizes.
  • SEM Scanning Electron Microscopy
  • Staining of the hydrogel or fibers may be required during the imaging process.
  • the loaded syringes were then loaded into a syringe fixture (Instron) attached to a MTS Criterion 43 mechanical tester.
  • the gel was injected out of the syringe through a 27 gauge needle (1 ⁇ 2′′ length, BD) at a crosshead speed of 1 mm/sec. Representative displacement curves are shown in FIG. 2I .
  • the 150 ⁇ m and 75 ⁇ m groups both resulted in acceptable injection profiles. The profiles are similar as both groups produce gel beads smaller than the 210 ⁇ m inner diameter of the 27 gauge needle.
  • Length distribution of the fibers dispersed throughout the hydrogel material were determined through measurement of fibers seen in contrast light microscopy images using ImageJ ( FIG. 2J , K).
  • SEM Sccanning Electron Microscopy
  • reaction buffer 0.1M sodium phosphate, pH 8.0, containing 1 mM EDTA
  • the three peaks corresponding to at 6 ppm were integrated and divided over the integrated value at 2 ppm.
  • the integrated value at 2 ppm was set to 3.
  • the three peaks at 6 ppm correspond with the three hydrogens associated with the carbons on the acrylate group (3 total hydrogens expected per acrylate group present).
  • the 2 ppm peak corresponds to the hydrogens associated with the acetyl group, present on each repeat unit of hyaluronic acid (3 per repeat unit).
  • the degree of substitution is thus the summed integrated area of the three 6 ppm peaks divided by the integrated area of the 2 ppm peak to give the fraction of HA repeat units with a acrylate group.
  • the acrylation degree percentage is that fraction converted to a percentage by multiplying by 100%.
  • the beads of different sizes were prepared using screens with mesh sizes of 1 mm, 250 ⁇ m, 150 ⁇ m, and 90 ⁇ m.
  • the particles were assessed for injectability (assessment from plastic surgeons) and rheological properties.
  • the 1000- ⁇ m beads were not injectable as their diameter was much larger than the bore size of a 25-gauge needle, while the 90- ⁇ m beads were heavily damaged in the beading process; therefore, both sizes were excluded from further study.
  • the rheological properties of the 250 ⁇ m and 150- ⁇ m beads are shown in FIG. 3 .
  • the storage modulus decreases slightly when the solid plug of material is formed into beads, but the resulting beads are within our target stiffness range and can be made stiffer or softer by changing the initial formulation.
  • the 250- ⁇ m and 150- ⁇ m beads showed similar rheological properties and both were suitable for future study.
  • the beaded formulation was next tested head-to-head against Juvedérm Voluma® in a rabbit subcutaneous injection model. Following histology, a blinded assessment of the tissue slides was done [need to bring in method from CRO]. Table 2 shows the rating scale that was used to assess the excised samples for three different categories (inflammation, edema, and fibrosis). This is a similar test format that will be required in the ISO10993 testing package for grading intracutaneous reactivity. As shown in Table 3, the beaded formulation disclosed herein resulted in lower overall effects on inflammation, edema, and fibrosis compared to Juvedérm Voluma.
  • PCL polycaptrolactone
  • FIG. 4C shows the effect of HA concentration (mg/ml) on shear storage modulus of the composite prepared under the same HA MW and fiber loading conditions
  • FIG. 4D shows the effect of HA concentration (mg/mi) on compression storage modulus of the composite prepared under the same HA MW and fiber loading conditions.
  • the pre-formed composite particles are mixed with high and low crosslinking densities (stiffness) and the advantages of both types of particles (stiffer, slower degrading, and longer lasting; vs. more porous, better cell infiltration, and vascularization) are combined.
  • the ratio of the two types of composite particles is another novel tunable parameter.
  • Tissue ingrowth was characterized by MRI imaging and histological analysis ( FIG. 5A-5B ) in comparison with the Juvéderm Voluma filler. Due to differences in water content between the synthetic and host tissue as illustrated by the MRI analysis, the scaffold appears a bright white. Over time, the host tissue surrounding the injection site begins to infiltrate, forming new tissue. This may translate into a semi-permanent injectable, wherein the scaffold remains present for long enough for the host tissue to repair the defect site but is remodeled by native host tissue. This is in direct contrast to a traditional HA hydrogel (sans fibers) that the body encapsulates and is only present for as long as the filler is able to hold up to degradation mechanisms ( FIG. 5B ).
  • a traditional HA hydrogel sin fibers
  • the nanofiber concentration had the biggest influence at 30 days post injection.
  • the fibers help guide the tissue ingrowth and are therefore critical for the extended volume retention seen in the best performing composite formulations.
  • the fully-reacted, particulated formulation of the LS series of the composite beads described above shows superior swelling properties when compared to commercial subdermal fillers such as Juvedérm. Specifically, the significant post-procedure swelling observed with Juvedérm injection in the rodent MRI model is not seen with the LS composite, enabling more of a “what you see is what you get” appearance that is desired by clinicians.
  • HA concentrations, fiber loading, and crosslinking for the current particulated composite form is ongoing and are expected to restore comparable durability to existing commercial standards while retaining enhanced volumization, lessened swelling, and more natural feel.
  • the degree of swelling has been characterized and plotted in FIG. 6A-C .
  • Tan ⁇ quantifies the balance between energy loss and storage. A higher Tan ⁇ indicates more liquid-like properties, whereas lower tan ⁇ suggests more solid-like properties, regardless of the modulus or viscosity.
  • the LS beaded composite has lower tan ⁇ measure ( FIG. 7A ) than marketed fillers while retaining a similar stiffness profile ( FIG. 7B ).
  • the more solid-like properties reflect that of in vivo fat, the current gold standard for soft tissue reconstruction ( FIG. 7C ).
  • the injectable formulation comprises vials of lyophilized powder cakes that are immediately reconstituted prior to injection. This is a workflow similar to that used in Botox injections.
  • a two-syringe system is used to rehydrate the composite. Clinicians would connect the two syringes, rehydrate, and then immediately inject the formulation.
  • a formulation for use with a single syringe is used, wherein the beads are rehydrated in the manufacturing facility during packaging and are ready to inject upon opening the package.
  • a syringe containing lyophilized powder is provided along with a vial comprising reconstitution fluid.
  • the fluid is drawn up from the vial and into the syringe to mix with the powder.
  • a major advantage of the composite structure described in the Examples above is that the mechanical properties of the nanofiber phase of the fiber-hydrogel composite changes little in the dried or frozen state, as opposed to most hydrogel components known in the art.
  • the fiber fraction can help maintain the overall composite microstructure.
  • the composite With the correct lyophilization cycle and formulation, the composite can be lyophilized, while still remaining as distinct beads upon rehydration.
  • the composite gel is made into beads by forcing the gel through a 250 ⁇ m screen.
  • the beads are injected into three 8 mm diameter molds and immediately tested for rheology (“Beads” group in FIG. 9A-B ).
  • the remaining bead volume was frozen in a ⁇ 80° C. incubator then placed in pre-cooled Labconco® Triad® lyophilizer for 24 hours at a shelf temperature of ⁇ 10° C. followed by secondary drying for 24 hours at 20° C.
  • the lyophilized cake occupied the same volume in the vial as the frozen sample before lyophilization, indicating the cake did not begin to melt during lyophilization.
  • the beads were rehydrated to exactly replace the water mass lost (as measured by weight).
  • the reconstituted gel could not be loaded into a syringe via aspiration, but when passed between syringes with a luer-lock connector, the gel beads that were initially stuck firmly to one another were able to be dispersed into individual beads.
  • the beads When tested for rheology (“Post-Lyophilization” group in FIG. 9A-B ), the beads were far stiffer, with greatly increased Storage Moduli and Young's Moduli. This is caused by the diffuse hydrogel structure collapsing into a denser biphasic structure. The injectability, the physical properties, and the porosity are all affected by the lyophilization process.
  • the beads were formulated as hypotonic (deionized water used instead of PBS).
  • 1 cc of the beads are loaded into Labconco® lyophilization vials, to which 1 cc of isotonic solution is added and further 1 cc of deionized water is added to have a total solution volume of 3 cc in the vial, with the beads dispersed throughout the volume.
  • the isotonic solution was either A: 3% sucrose, 3% trehalose, 0.3% NaCl and 2 mg/mL free 700 k HA or B: PBS with 2 mg/ml free 700 k HA.
  • the vials are snap frozen in liquid nitrogen, then lyophilized at ⁇ 30° C. shelf temperature and 10 Pa vacuum pressure for 48 hours, with 24 hours of secondary drying with the temperature raised to 20° C.
  • the group diluted in PBS buffer was also easily aspirated into the syringe and behaved similarly to the sucrose-trehalose group but had a raised storage modulus that was 87% higher than the initial, pre-beaded modulus and 154% higher than the beaded gel prior to lyophilization. This indicates that some microstructure changes were still occurring in the PBS group, even if the particles remained as distinct beads.
  • the bead sizes were varied by varying the mesh size of the screens used in the beading process.
  • Bead screens with openings over 250 ⁇ m were excluded, since the resulting beads need to have at least one dimension that is sized smaller than the inner diameter of the syringe needle.
  • the needles commonly used for dermal filler applications range from 25-gauge to 30-gauge, with an inner diameter of from 260 ⁇ m to 160 ⁇ m.
  • Smaller beads were attempted via a screen with 90- ⁇ m openings, but the small mesh size disrupted the composite gel microarchitecture; the 90- ⁇ m opening size was smaller than the length of many of the individual fibers, which caused the fibers and gel to be ripped apart, instead of being cut into homogenous gel-fiber composite.
  • the processing with a 90- ⁇ m screen did not produce enough material for characterization.
  • the beads produced by the 250- ⁇ m and 150- ⁇ m screens ( FIG. 10B ) produced gels with similar rheological properties to beads formed as in FIG. 10A , especially storage modulus and tan delta, appropriate for dermal fillers.
  • the tan delta is the rheological loss modulus divided by the storage modulus, which means that a lower tan delta number equates to a more “solid-like” as opposed to “liquid-like” material.
  • the tan delta for samples the process described above is shown in FIG. 10C .
  • the dermal filling industry has been trending toward lower tan delta values over time. This is a trend toward a more solid-like feel, which has a better lifting capacity for filling a skin defect.
  • the fiber-hydrogel composite material furthers that trend towards better lifting capacity and maintains that trait even after the beading process.
  • the tan delta data were obtained during an amplitude sweep at 1 Hz from 0.1-10% amplitude, averaging the tan delta values from 1-10% amplitude on Ares G2 rheometer.
  • Composite value is from the 150- ⁇ m bead group shown in FIG. 10C .
  • a moderately-sized defect (cylinder: ⁇ -10 mm ⁇ h-13 mm; ⁇ 1-cc) was generated in the inguinal fat pad of the New Zealand rabbit using a 10-mm biopsy punch, and a saline displacement method was used to ensure consistency in volume of the removed fat in different animals.
  • the 1 cc volume is larger than the bolus size of individual fat grafts used currently for soft tissue restoration and serves as a relevant proof of concept.
  • the in situ-forming and beaded composite, or control hydrogels which assumed the defect shape ( FIG. 11A ).
  • 11B shows host blood vessel infiltration into different graft matrices (150-Pa composite, 150-Pa hydrogel, and 80-Pa hydrogel) on POD 14. Endothelial cells were stained with CD31 in red and cell nuclei were stained with DAPI in blue. Fibers were F8BT-labelled in green. Scale bar: 100 ⁇ m.
  • Tissue samples were harvested at 13 weeks in vivo from a rat with LS-5 composite beads from the experiment in Example 5.
  • the tissue samples were fixed, sectioned, and stained with H&E and Masson's Trichrome stains.
  • the H&E-stained histology image ( FIG. 12 ) shows the growth/infiltration pattern of the cells, which recapitulate the underlying bead morphology.
  • various composite beads with different fiber density are implanted to evaluate cell proliferation, morphological changes, migration behavior.
  • microbeads were determined to be stable for 6 months.
  • Rheological tests to determine structural integrity are performed at room temperature at 1 month, 3 months, 6 months, 9 months, 12 months and 24 months on hydrated form, and dehydrated form of the heads.
  • Various composite heads with different hydrogel molecular weight, acrylation degree, fiber concentration, maleimide degree, and cross-linking density are tested for their stabilites.
  • the beaded formulation remains easily injectable through clinically-relevant 27- to 31-gauge or 16- to 31-gauge needles and offers several improvements over the in situ gelling prototype.
  • the beaded formulation enables a single syringe delivery system for improved ease of use. With much greater surface area, the lyophilized beads rehydrate more quickly, so extensive two-syringe mixing will no longer be required.
  • the beaded formulation enables higher concentrations of hyaluronic acid, nanofibers, and crosslinker to be used in the formulation. Previously, the maximum concentrations were governed by viscosity and injection force. By moving to particularized beads, the constituent concentrations are no longer rate limiting and the team can further modify stiffness and enhance durability.
  • the beaded formulation enables enhanced stability.
  • the pre-reacted, beaded form of the composite is much more robust to temperature, humidity, and light variation than the unreacted form, and has had no change in properties after multiple cross-country shipments.
  • the beaded formulation provides an enhanced cell and tissue delivery scaffold.

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