CN116041055B

CN116041055B - 4D printing and deformation control method for biological ceramic composite material

Info

Publication number: CN116041055B
Application number: CN202211684991.0A
Authority: CN
Inventors: 邹斌; 陈清华; 王鑫峰; 周兴国; 刘继凯; 李磊; 来庆国
Original assignee: Shandong University
Current assignee: Shandong University
Priority date: 2022-12-27
Filing date: 2022-12-27
Publication date: 2023-10-17
Anticipated expiration: 2042-12-27
Also published as: CN116041055A

Abstract

The invention belongs to the technical field of 4D printing, and relates to a 4D printing and deformation control method of a biological ceramic composite material, which comprises the following steps: respectively preparing a polyethylene glycol diacrylate/biological ceramic paste system and a methacryloylated gelatin/biological ceramic paste system, wherein the two systems are matched to be used as a 4D printing paste; creating a three-dimensional model, and designing a model structure and material distribution according to the model deformation requirement and the deformation characteristics of the biological ceramic composite paste state system; and (3) placing the two printing pastes into a multi-material photo-curing SLA printer, and performing distributed cross printing forming based on a three-dimensional model to be prepared. The invention prepares the biological ceramic composite material suitable for 4D printing, and solves the problems that the ceramic 4D reversible large deformation structure is difficult to manufacture and the mechanical strength of the hydrogel is low. The material distribution and the model structure are designed, and the autonomous controllable deformation of the biological ceramic composite material under the stimulation of the solution is realized by controlling a 4D printing process method.

Description

4D printing and deformation control method for biological ceramic composite material

Technical Field

The invention belongs to the technical field of 4D printing, and particularly relates to a 4D printing and deformation control method of a biological ceramic composite material.

Background

The disclosure of this background section is only intended to increase the understanding of the general background of the invention and is not necessarily to be construed as an admission or any form of suggestion that this information forms the prior art already known to those of ordinary skill in the art.

The 4D printed product can realize controllable change of shape, performance and function under the stimulation of external conditions, and has wide application prospect in the biomedical fields such as tissue engineering, medical appliances, drug delivery carriers and the like. But few shape memory materials are available for 4D printing and have good mechanical properties and high biocompatibility. The biological ceramic material has high mechanical strength and hardness, good thermal stability and chemical stability and good biocompatibility. Among them, hydroxyapatite is a main inorganic component of human bone tissue, and is most widely used in the field of hard tissues. But bioceramic materials have the characteristics of being hard and brittle and having low flexibility, and cannot realize large structural deformation. At present, 4D printing of ceramic materials has unidirectionality and unidirectional thermal driving, and can finish self-assembly, self-repair or self-induction in the sintering process according to the internal stress after resin curing or the flexible characteristic of an elastic ceramic precursor, and the ceramic materials do not have deformation characteristics after sintering.

Biological materials for 4D printing still have a number of limitations in terms of stimulus response mechanisms. The driving modes suitable for human body environment include thermal driving, body fluid driving and PH driving. Thermally driven type deformation materials require artificial morphological transformations, which can be very difficult if the sample volume is small; and the 4D structure needs to be placed in a thermal environment to actively deform, which requires that the whole object and even the surrounding environment where the object is placed need to be heated, which is very inconvenient in the practical application process. In addition, strongly varying pH values are unsuitable because they may negatively impact cell viability. Body fluid actuation is a relatively gentle, simple actuation. Hydrogels are widely used in liquid-driven deformable biomaterials. However, hydrogel materials for 4D printing, such as methacryloylated gelatin (GelMA) and polyethylene glycol diacrylate (PEGDA), have disadvantages of easy deformation of structure after molding and poor rigidity.

Disclosure of Invention

In order to solve the problems, the invention provides a 4D printing and deformation control method of a biological ceramic composite material. The invention prepares the biological ceramic composite material suitable for 4D printing, and solves the problems that the ceramic 4D reversible large deformation structure is difficult to manufacture and the mechanical strength of the hydrogel is low. The material distribution and the model structure are designed, and the autonomous controllable deformation of the biological ceramic composite material under the stimulation of the solution is realized by controlling a 4D printing process method.

In order to achieve the above purpose, the present invention adopts the following technical scheme:

in a first aspect of the present invention, there is provided a 4D printing and deformation control method of a bioceramic composite, comprising:

respectively preparing a polyethylene glycol diacrylate/biological ceramic paste system and a methacryloylated gelatin/biological ceramic paste system, and matching the two paste systems to be used as a 4D printing paste;

creating a three-dimensional model, and designing a model structure and material distribution according to the model deformation requirement and the deformation characteristics of the biological ceramic composite paste state system;

placing the two printing pastes into a multi-material photo-curing SLA printer, and based on a three-dimensional model to be prepared, respectively utilizing the two printing pastes to perform cross printing forming according to functional requirements, design schemes and material distribution;

and taking out the mold after printing, and washing out uncured paste around the molded part to obtain the product.

In a second aspect of the present invention, there is provided a 4D printed bioceramic composite prepared by the method described above.

In a third aspect of the present invention, there is provided a deformation control method of a 4D printed bio-ceramic composite material, comprising:

applying solution stimulation to the whole structure of the 4D printing biological ceramic composite material to comprehensively deform polyethylene glycol diacrylate/biological ceramic and methacryloylated gelatin/biological ceramic;

or, applying a solution stimulus to the local structure to cause the structure to undergo local stretching or crimping.

The beneficial effects of the invention are that

(1) After the methacryloyl gelatin is solidified, crosslinked and formed, the methacryloyl gelatin is dehydrated to generate large-size shrinkage, and spontaneously expands when immersed in water, so that the methacryloyl gelatin plays a role of an elastic element in a structure, can realize different percentages of linear expansion, and can realize folding performance of a printing structure by the mechanical design of an island-bridge structure.

(2) The PEGDA/HAP paste system generates residual stress due to different crosslinking degrees of organic matters on the upper surface and the lower surface after solidification, and the residual stress causes the test piece to curl, so that the autonomous deformation of the biological ceramic complex structural member is realized.

(3) The invention compounds biological ceramic with methacryloylated gelatin and polyethylene glycol diacrylate, and can improve the hard brittleness and flexibility of ceramic, and has large deformation characteristic after forming. The characteristics of softness and easy deformation of the hydrogel can be improved, and 4D printing of the deformable biological ceramic composite material can be realized.

(4) The biological ceramic composite material prepared by the 4D printing process and the deformation control method has a polymorphic memory effect and a reversible shape memory effect, and can be subjected to four-dimensional transformation under mild solution stimulation. Through the design of structure and material distribution, the integral printing and forming are realized, and the inherent functional gradient of the biological ceramic composite material is realized. Different parts are composed of biological ceramic composite materials with different microstructures and different swelling properties. The individual shape recovery of the various portions of material will be activated continuously when the appropriate stimulus is applied. Thus, orderly deformation of the bioceramic composite can be achieved by appropriate control of the material properties of the various parts.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention.

FIG. 1 shows a leaf model designed by means of the present invention in example 1;

FIG. 2 a leaf form of example 1 printed by means of the 4D method of the invention;

FIG. 3 reversible deformation characteristics of leaf forms printed by means of 4D according to the invention in example 1;

FIG. 4 a leaf model designed by means of the present invention in example 2;

FIG. 5 leaf form of example 2 printed by means of the 4D method of the invention;

fig. 6 the controlled autonomous deformation properties of leaf forms printed by means of the 4D method of the invention in example 2.

Detailed Description

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

A 4D printing method of a bioceramic composite, comprising the steps of:

s1, preparing a biological ceramic composite paste system: mixing biological ceramic particles and polyethylene glycol diacrylate in proportion to obtain printing paste; the biological ceramic particles, the methylacryloyl gelatin and the water are mixed according to a proportion to obtain the printing paste.

S2, creating a three-dimensional model by adopting Solidworks three-dimensional modeling software, and designing a model structure and material distribution according to model deformation requirements and deformation characteristics of a biological ceramic composite paste state system. The three-dimensional model is saved in STL format.

S3, placing the two printing pastes into a multi-material photo-curing SLA printer. Based on the three-dimensional model to be prepared, the two biological ceramic pastes are respectively utilized to be formed by cross printing according to functional requirements, design schemes and material distribution.

And S4, taking out the mold after printing the whole mold, and washing the mold with water at 50 ℃ to remove uncured paste around the molded part.

In some embodiments, in step S1, the bioceramics include, but are not limited to, one or more of hydroxyapatite, tricalcium phosphate, tricalcium silicate, tri-magnesium phosphate, and magnesium trisilicate.

In some embodiments, the bioceramic particle shapes include, but are not limited to, spheres, rods, needles, and flakes, all medical grade, with particle sizes less than 50 μm.

In some embodiments, in the step S1, the content of the bioceramics in the two paste systems is 10wt% to 50wt%.

In some embodiments, in step S1, the molecular weight of the PEGDA is 400-1000 Da.

In some embodiments, in step S1, gelMA has a molecular weight of 100-200 kDa and a degree of methacryloyl substitution of 30-90%.

In some embodiments, in the step S2, the deformation characteristics of the bioceramic composite need to be fully considered for the model structure and the material distribution. After the polyethylene glycol diacrylate/biological ceramic material is solidified, residual stress is generated due to different crosslinking degrees of internal organic matters, and the residual stress can cause spontaneous curling of the structure. The methacryloylated gelatin/bioceramic material can play the role of an elastic element in the structure due to water loss shrinkage and water absorption expansion after solidification, realize linear expansion with different percentages, and realize folding performance of the printing structure by mechanical design of an island-bridge structure.

In some embodiments, in the step S3, the cross printing manner is: firstly, printing a polyethylene glycol diacrylate/biological ceramic paste system, wherein the layering thickness of the polyethylene glycol diacrylate/biological ceramic paste system is 50 mu m; secondly, printing a methacryloylated gelatin/bioceramic paste system, wherein the layering thickness of the system is 100 mu m; the cross printing forming rule of different material areas is that after two layers of polyethylene glycol diacrylate/bioceramics are cured, one layer of methacryloylated gelatin/bioceramics is cured.

The invention also provides a deformation control method of the 4D printing biological ceramic composite material, which comprises the following steps:

after the methacryloylated gelatin/bioceramic is solidified and formed, the shrinkage becomes smaller when dried, and the swelling and the elongation become larger when wetted, so that the linear shrinkage and shrinkage of the related structure can be realized.

Residual stress is generated by different crosslinking degrees of organic matters on the upper surface and the lower surface after the polyethylene glycol diacrylate/biological ceramic material is solidified, the residual stress causes the regional structure of the material to curl during drying, the material absorbs water and swells after being immersed in water, and the upper surface and the lower surface can be restored to the shape of the model design after the swelling balance is achieved.

The deformation mechanism and the deformation degree of the two biological ceramics after solidification are different, the deformation of the methacryloylated gelatin/biological ceramics is larger than that of polyethylene glycol diacrylate/biological ceramics, and the two biological ceramics can form superposition benefits and different deformation effects.

The 4D printing biological ceramic composite material can implement regular deformation change according to the stimulation of the surrounding environment. The method can apply solution stimulation to the whole structure to comprehensively deform polyethylene glycol diacrylate/bioceramic and methacryloylated gelatin/bioceramic, and can also apply solution stimulation to the local structure to complete local expansion or curling deformation of the structure.

The invention will now be described in further detail with reference to the following specific examples, which should be construed as illustrative rather than limiting.

Example 1:

fig. 1 is a leaf model of a design, comprising three parts of leaves, she Tuo and petioles. In this embodiment, the bioceramic composite designs two areas according to the deformation requirement, wherein the blade support (dark gray area) is GelMA/HAP, the blade and the blade stem (light gray area) are PEGDA/HAP, and the process of printing the model 4D is as follows:

(a) Preparation of PEGDA/HAP paste system: mixing hydroxyapatite particles and PEGDA in proportion to obtain a printing paste, wherein the hydroxyapatite accounts for 40 weight percent of the paste, and the specific steps comprise:

1) Dispersing hydroxyapatite powder into deionized water, ball milling and refining for 10 hours (the grain diameter of the refined ceramic powder is 20 nm-15 mu m), taking out, filtering and freeze drying.

2) PEGDA having a molecular weight of 400 and 0.5wt% of photoinitiator I2959 were homogeneously mixed. Adding the ball-milled hydroxyapatite powder into the premix, performing ultrasonic dispersion for 20min, and mechanically stirring for 2h to obtain the final product.

(b) Preparing a GelMA/HAP paste system: mixing hydroxyapatite particles, gelMA and water according to a proportion to obtain a printing paste, wherein the ratio of GelMA to water is 1:2, the hydroxyapatite accounts for 30 weight percent of the GelMA, and the specific steps comprise:

1) GelMA is dissolved in water, a photoinitiator is added into the mixed solution, and the mixed solution is magnetically stirred at 50 ℃ until 4 weight percent of photoinitiator VA-086 is completely dissolved to form a premix.

2) Adding hydroxyapatite powder into the premix at 50 ℃ while mechanically stirring, and uniformly mixing to obtain the final product.

(c) Creating a leaf three-dimensional model by adopting Solidworks three-dimensional modeling software: the length of the minor half axis of the elliptic vane is 1mm, the length of the major half axis is 5-4.5 mm, the width of the She Tuo is 0.5mm, the width of the vane handle is 1mm, and the overall thickness of the model is 0.5mm. The three-dimensional model is saved in STL format.

(d) The two print pastes were placed into a stereoscopic light curing (SLA) additive manufacturing apparatus that supports multi-material printing.

(e) And importing the leaf model into SLA-3D printer equipment, and cross-printing and forming different structural parts according to a certain rule according to functional requirements.

(f) Firstly, printing and forming blade and blade handle parts, adopting a PEGDA/HAP paste state system as a material, wherein the printing parameters are as follows: the laser power is 70mw, the laser scanning speed is 3.9m/s, the laser scanning interval is 100 mu m, and the printing layering thickness is 50 mu m; secondly, printing and forming She Tuo parts, wherein a GelMA/HAP paste state system is adopted as a material, and the printing parameters are as follows: laser power 170mw, laser scanning speed 4.0m/s, laser scanning interval 45 μm, printing layering thickness 100 μm; the cross printing forming rule of different structures is that one layer of GelMA/HAP is cured after every two layers of PEGDA/HAP are cured.

(g) After the entire mold is printed, the mold is taken out, and uncured paste around the molded article is washed with water at 50 ℃.

(h) According to the present embodiment, the shape of the leaf print after drying as shown in fig. 2 and She Tuo can be changed regularly according to the surrounding environment. The GelMA/HAP She Tuo is dried to reduce shrinkage, and swells and stretches when wetted, so that the She Tuo part can linearly shrink and shrink, and further the expansion of the blade to the outside and the curling to the inside are controlled.

(i) According to the embodiment, the shape of the leaf printed piece after drying is as shown in fig. 2, and the leaf can be regularly deformed and changed according to the surrounding environment. Residual stress is generated by different crosslinking degrees of organic matters on the upper surface and the lower surface of the PEGDA/HAP blade after solidification, the blade is curled by the residual stress during drying, the blade absorbs water and swells when the blade is immersed in water, and the blade can be flattened after the swelling balance of the upper surface and the lower surface is achieved.

(j) According to this embodiment, the leaf print is shaped as shown in fig. 2 after drying, and the leaf can be deformed and changed regularly according to the stimulus of the surrounding environment. The leaf can realize bidirectional closing and flattening under the comprehensive deformation of She Tuo and the leaf. After the printing of the leaves is finished, the dried leaves She Tuo shrink to form a tensile force on the leaves, the leaves shrink, and the leaves overlap with each other to form a curled closed state; after immersing the curled blades in water, both blades and She Tuo reach swelling equilibrium, the blades return to a flattened state. And further placing the blade forming part subjected to swelling balance into an absolute ethyl alcohol solution for dehydration, wherein the blades can be reversely curled due to the different wettability and water loss rate of the upper surface and the lower surface of the blades. And taking out the leaves, volatilizing the alcohol, and deforming the leaves again due to internal stress of the PEGDA/HAP part and water loss shrinkage of the GelMA/HAP part. The self-deformation process of the leaf is shown in fig. 3, and the whole deformation process is reversible.

Example 2:

fig. 4 is a leaf model of a design, comprising three parts of leaves, she Tuo and petioles. In this embodiment, the bioceramic composite designs two areas according to the deformation requirement, wherein the blade support (dark gray area) is GelMA/HAP, the blade and the blade stem (light gray area) are PEGDA/HAP, and the process of printing the model 4D is as follows:

(h) According to the present embodiment, the shape of the leaf print after drying as shown in fig. 5 and She Tuo can be regularly deformed according to the surrounding environment. The GelMA/HAP She Tuo is dried and then is contracted to be smaller, and is wetted and swelled to be elongated, so that the She Tuo part can be contracted and contracted in the same direction, and the blades can be controlled to curl and stretch in the same direction.

(i) According to this embodiment, the leaf print is shaped as shown in fig. 5 after drying, and the leaf can be deformed and changed regularly according to the surrounding environment. The PEGDA/HAP blade generates residual stress due to different crosslinking degrees of organic matters on the upper surface and the lower surface after solidification, and the blade is stimulated at different parts so as to control different blades to form different degrees of curls.

(j) According to this embodiment, the leaf print is shaped after drying as shown in fig. 5, and the leaf is controllable according to the regular change of the surrounding stimulus. The leaves are formed to be closed and flattened in a two-way mode under the comprehensive deformation of She Tuo and the leaves. After the printing of the leaves is finished, the leaves are regularly retracted and contracted, so that the leaves are unfolded to two sides. Residual stress is generated at the PEGDA/HAP part due to different crosslinking degrees of organic matters on the upper surface and the lower surface after solidification, the residual stress causes the blade to curl, water drops on the upper surface of the blade, and the blade can curl reversely due to different wettability and swelling degrees of the upper surface and the lower surface of the blade. The deforming effect of this type of structure is shown in fig. 6.

By the design of the material distribution and the model structure in the embodiment 1 and the embodiment 2, the formed leaves can be closed at random in different degrees, and the change rule is controllable.

The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A 4D printing method of a bioceramic composite, comprising:

taking out the mold after printing, and washing out uncured paste around the molded part to obtain the product;

the cross printing mode is as follows: firstly, printing a polyethylene glycol diacrylate/biological ceramic paste system, wherein the layering thickness of the polyethylene glycol diacrylate/biological ceramic paste system is 50-60 mu m; secondly, printing a methacryloylated gelatin/bioceramic paste system, wherein the layering thickness is 100-120 mu m; the cross printing forming rule of different material areas is that after every two layers of polyethylene glycol diacrylate/bioceramics are cured, one layer of methacryloylated gelatin/bioceramics are cured;

after the polyethylene glycol diacrylate/biological ceramic material is solidified, residual stress is generated due to different crosslinking degrees of internal organic matters, and the residual stress causes spontaneous curling of the structure; the methacryloylated gelatin/biological ceramic material has the functions of water loss shrinkage and water absorption expansion after solidification, plays the role of an elastic element in the structure, realizes linear expansion with different percentages, and realizes folding performance of the printing structure by the mechanical design of an island-bridge structure;

the content of the biological ceramic in the polyethylene glycol diacrylate/biological ceramic paste system and the methacryloylated gelatin/biological ceramic paste system is 10wt% -50 wt%;

the biological ceramic is one or more of hydroxyapatite, tricalcium phosphate, tricalcium silicate, magnesium phosphate and magnesium trisilicate.

2. The 4D printing method of the bioceramic composite according to claim 1, wherein the shape of the bioceramic particles includes sphere, rod, needle and flake, which are all medical grade, and have a particle size of less than 50 μm.

3. The 4D printing method of the bioceramic composite according to claim 1, wherein the molecular weight of polyethylene glycol diacrylate PEGDA is 400-1000 Da.

4. The 4D printing method of the bioceramic composite according to claim 1, wherein the molecular weight of the methacrylic acid acylated gelatin GelMA is 100-200 kDa, and the degree of substitution of methacryloyl is 30-90%.

5. A 4D printed bioceramic composite prepared by the method of any one of claims 1-4.

6. A deformation control method of a 4D printed bio-ceramic composite material, comprising:

applying a solution stimulus to the overall structure of the 4D printed bioceramic composite of claim 5 to cause a combined deformation of polyethylene glycol diacrylate/bioceramic and methacryloylated gelatin/bioceramic;