CN116212120A - Injectable self-healing hydrogel for bone repair and preparation method and application thereof - Google Patents

Abstract

The invention belongs to the field of biomedical materials, and relates to injectable self-healing hydrogel for bone repair and a preparation method and application thereof. The invention modifies the natural biomass waste chitin/chitosan with good biocompatibility and low cost, and simultaneously introduces Schiff base bond and acylhydrazone bond into the natural polysaccharide network. On the basis, the functional hydrogel with excellent performance is prepared by utilizing carboxyethyl chitin grafted adipoyl dihydrazide, carboxyethyl chitosan grafted dodecane and carboxyl polyvinyl alcohol grafted benzaldehyde, and the contradiction among the mechanical strength, injectability, biodegradability and self-healing capacity of the hydrogel is solved. The composite hydrogel has excellent adhesion performance and degradation rate matched with bone tissue regeneration, so that the problems of poor adhesion of a stent material, tissue regeneration inhibition and the like in the current clinical application are solved, and a biomedical stent with extremely wide application value and market prospect is produced.

Description

Injectable self-healing hydrogel for bone repair and preparation method and application thereof

Technical Field

The invention belongs to the field of biomedical materials, and particularly relates to injectable self-healing hydrogel for bone repair and a preparation method and application thereof.

Background

In recent years, bone tissue defects caused by wounds, infections and congenital malformations are increasing, and advanced biomedical materials are urgently needed to meet the complex treatment requirements. The biological scaffold material is not only a physical scaffold for the bone defect area, but also a vehicle for releasing growth factors to accelerate bone tissue reconstruction. Various materials including allogeneic bone, xenogeneic bone, metal bone cement, bioglass, and polymers have been used so far for experimental exploration of bone regeneration. However, allogeneic bone, xenogeneic bone sources are limited, costly, poorly adherent, donor-scarce and poorly immunogenic, limiting their practical use. The prefabricated implantation stent has the problems of poor adaptability, insufficient biocompatibility, large surgical exposure area, mismatching of the degradation rate of the stent material and the growth rate of new bone tissue, increased bone loss, increased recovery time and pain of patients due to secondary surgery and the like, and the practical application of the prefabricated implantation stent is limited. In contrast, dynamic hydrogels have good injectability and are considered to be the optimal carrier for tissue engineering growth factor delivery.

It is well known that self-healing behavior is widely found in many biological tissue structures, and has prompted scientists to explore, without undue experimentation, the use of dynamic hydrogels comprising self-healing, injectability in biomedical engineering. It is worth noting that since the hydrogel structure functions highly similar to the extracellular matrix, and can effectively regulate the behavior and function of stem cells, including guiding and accelerating the migration and osteogenic differentiation of mesenchymal stem cells, the stem cell carrier hydrogel can be used in the field of rapid bone tissue regeneration. In particular, the mechanical strength of the hydrogel has positive regulation effect on stem cell differentiation. However, high mechanical strength results in a considerable sacrifice in the dynamic properties of hydrogels due to the low exchange kinetics of stable gel network cross-links, while highly dynamic reversible cross-linked networks have rapid self-healing behavior, injectable behavior, etc. while also weakening their gel mechanical strength. Under physiological conditions, the acylhydrazone bond tends to be kinetically "locked" which gives hydrogels with a robust cross-linked network and mechanical strength, but lacks very dynamic reversible properties and does not self-heal in the absence of a catalyst. Although the acylhydrazone bond enhanced hydrogel can effectively stabilize the structure of a bone defect area, the bone repair gel still needs to have enough dynamic reversible characteristics to meet the requirements of rapid adaptive filling, minimally invasive injection and the like of irregular defect positions. The hydrogel has self-healing property and injectability due to the dynamic bonds such as hydrogen bonds, schiff base bonds, host-guest actions and the like, but has lower mechanical strength. At present, many reports on hydrogel materials for promoting bone repair are reported, and reports on hydrogel engineering scaffolds with high strength performance for promoting bone tissue regeneration are also few, but hydrogel engineering scaffolds with both macroscopic stability and microscopic dynamics are very limited.

Disclosure of Invention

Aiming at the defects of the prior art, the invention modifies the natural biomass waste chitin/chitosan with good biocompatibility and low cost, and simultaneously introduces a Schiff base bond and an acylhydrazone bond into a natural polysaccharide network. On the basis, the functional hydrogel with excellent performance is prepared by utilizing carboxyethyl chitin grafted adipoyl dihydrazide (CECT-ADH), carboxyethyl chitosan grafted dodecane (CES-DOD) and carboxypolyvinyl alcohol grafted benzaldehyde (PVA-BA), so that the contradiction among the mechanical strength, injectability, biodegradability and self-healing capability of the hydrogel is solved. The hydrogel is endowed with proper mechanical strength by utilizing a strategy of compounding various dynamic bonds, so that the extracellular matrix microenvironment is effectively simulated, the differentiation of bone marrow mesenchymal stem cells is promoted, and further the regeneration of bone tissues is promoted. The composite hydrogel has excellent adhesion performance and degradation rate matched with bone tissue regeneration, so that the problems of poor adhesion of a stent material, tissue regeneration inhibition and the like in the current clinical application are solved, and a biomedical stent with extremely wide application value and market prospect is produced.

To achieve the above object, a first aspect of the present invention provides a method for preparing an injectable, self-healing hydrogel for bone repair, comprising the steps of:

(1) Synthesizing carboxyethyl chitin grafted adipic acid dihydrazide CECT-ADH;

dissolving carboxyethyl chitin in deionized water, adding adipic dihydrazide, morpholinoethanesulfonic acid, 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide into the solution, stirring the solution in a dark place for reaction, and obtaining a product CECT-ADH after dialysis and freeze drying;

(2) Synthesizing carboxyl ethyl chitosan grafted dodecanal CES-DOD;

introducing morpholine ethanesulfonic acid and sodium cyanoborohydride into a carboxyethyl chitosan solution, then dissolving dodecanal into ethanol, dripping into the solution under the condition of avoiding light, reacting the obtained mixture, dialyzing and freeze-drying to obtain a product CES-DOD;

(3) Synthesizing polyvinyl alcohol grafted benzaldehyde PVA-BA;

under the nitrogen atmosphere, adding 4-hydroxybenzaldehyde, 4-formylbenzoic acid and catalytic amount of anhydrous pyridine into a polyvinyl alcohol dimethyl sulfoxide solution, heating and stirring for reaction, adding succinic anhydride, cooling to room temperature after continuing the reaction, pouring into glacial ethyl ether for reprecipitation, and obtaining a product PVA-BA through redissolution, dialysis and freeze drying;

(4) Preparing hydrogel;

and respectively dissolving CECT-ADH, CES-DOD and PVA-BA in PBS buffer solution, then uniformly mixing CECT-ADH solution and CEC-DOD solution, then adding PVA-BA solution, rapidly and uniformly mixing the obtained mixed solution by vortex, transferring the mixed solution into a polytetrafluoroethylene mould, and curing to obtain the CECT-ADH/PVA-BA/CES-DOD hydrogel.

According to a preferred embodiment of the present invention, in step (1), the molar ratio of carboxyethyl chitin, adipic acid dihydrazide, morpholinoethanesulfonic acid, 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide is 1:1.8-2.2:4.5-5.5:02-0.3:02-0.3.

According to a preferred embodiment of the present invention, in the step (1), the temperature of the light-shielding stirring reaction is 20-30 ℃ for 6-36 hours.

According to a preferred embodiment of the present invention, in step (2), the molar ratio of dodecanal, morpholinoethanesulfonic acid, sodium cyanoborohydride, carboxyethyl chitosan is 1:40-45:8-12:8-12.

According to a preferred embodiment of the present invention, in the step (2), the dropping speed of the dodecanol solution is 1mL/30min-1mL/min, and the reaction temperature is 20-30 ℃ and the reaction time is 12-48h.

According to a preferred embodiment of the present invention, in step (3), the molar ratio of 4-hydroxybenzaldehyde, 4-formylbenzoic acid, polyvinyl alcohol and succinic anhydride is 1:6-10:4-6:4-6.

According to a preferred embodiment of the present invention, in step (3), the heating reaction is carried out at a temperature of 75 to 85℃for a period of 2 to 4 hours.

The reaction is continued for 2-10h after the succinic anhydride is added.

According to a preferred embodiment of the invention, in step (4), the pH of the PBS buffer is 7.2-7.6.

The PVA-BA solution was mixed with the CECT-ADH solution and the CES-DOD solution so that the amino/aldehyde ratio in the mixture was 1.0-3.0.

Mixing the PVA-BA solution with the CECT-ADH solution and the CES-DOD solution so that the solid content of the mixture is 1.0-5.0wt%; preferably, the PVA-BA solution has a concentration of 1.0 to 5.0 wt.%, the CECT-ADH solution has a concentration of 1.0 to 5.0 wt.%, and the CES-DOD solution has a concentration of 1.0 to 5.0 wt.%, preferably 1.2 to 5.0 wt.%.

The curing temperature is 37 ℃ and the curing time is 10-120min.

In a second aspect, the present invention provides a hydrogel produced by the above-described production method.

A third aspect of the present invention provides the use of a hydrogel as described above in the preparation of a bone repair material.

The degradation rate of conventional scaffolds is often not perfectly matched to the rate of new bone growth. Therefore, chitin is attracting attention as a natural polysaccharide with the second yield in nature due to its excellent biodegradability. Because lysozyme can act on N-acetamido on glucose ring in chitin, pure chitin has too high degradation speed in vivo, which is unfavorable for long-term bone reconstruction application. Compared with chitin, chitosan obtained after deacetylation is slowly degraded. By combining the principle that the degradation rate of the stent is highly matched with the growth rate of the blood vessel and the new bone, the hydrogel compositely constructed by the chitin and the chitosan has good degradation behavior, and secondary operation is effectively avoided. Therefore, chitin/chitosan-based hydrogels can be ideal biomedical scaffolds due to their inherent biocompatibility and adhesiveness.

According to the invention, the raw material chitin is subjected to derivatization treatment, the hydrazide group is introduced to facilitate construction of an acylhydrazone bond hydrogel network, the dodecanal and the carboxyethyl are introduced to the chitosan chain, the water solubility is promoted, and the adhesive group is introduced at the same time, so that adhesion between the hydrogel and the surface of biological tissues is facilitated. The high-strength self-repairing injectable biodegradable dynamic hydrogel can be obtained by regulating the ratio of chitin to chitosan and the ratio of grafted groups, the extracellular matrix microenvironment can be effectively simulated, the differentiation of bone marrow mesenchymal stem cells is promoted, the potential superior to that of commercial bone repair materials is shown in an in-vivo mouse skull defect model, the problems that bone repair products are incompatible in strength and self-adaptability, poor in adhesion performance, and unmatched in degradation rate and bone tissue growth rate in the current market are solved, and the bone repair preparation method has wide application prospect and market value.

Compared with the prior art, the invention has the technical advantages that:

(1) The prior art is mainly used for repairing bone defects, such as allogeneic bone, xenogeneic bone, metal brackets, bioglass, high-strength hydrogel and the like, and the bracket material is mostly prefabricated, has poor shape adaptability with the defects, has poor immunogenicity, high cost, complex preparation process and troublesome operation, and has insufficient biocompatibility to influence the repairing efficiency of the bone defects. According to the invention, the ocean waste chitin with abundant reserves and excellent biocompatibility is modified, so that the high-strength self-adaptive bone repair bracket can be prepared, and the repair of bone defects is accelerated.

(2) The hydrogel stent material prepared by the prior art has high strength and can play a role in bionic physical support on the defect, but most of the hydrogel stent material has no dynamic characteristic, so that the hydrogel stent material is not tightly attached to a wound in natural movement of a human body, has poor adhesiveness and can not provide a favorable environment for cell movement. The invention can utilize the advantages of abundant active groups of natural polysaccharide and the like, solves the problems of poor adhesiveness, insufficient dynamic characteristics and the like of the traditional commercial bone repair hydrogel scaffold, and prepares the hydrogel scaffold with a high-efficiency dynamic network, which can effectively attach to a bone defect in the moving process, effectively simulate the dynamic microenvironment of cells, promote stem cells to differentiate into bone cells and promote bone defect repair.

(3) The bone repair hydrogel scaffold prepared by the prior art has poor degradation performance in vivo, and hinders the growth rate and the space of new tissues in the bone repair process. The invention can solve the problem that the degradability of the existing scaffold is not matched with the growth rate of the new tissue, the obtained hydrogel scaffold has proper degradation rate and biocompatibility, can not cause inflammation and other problems, and greatly improves the healing efficiency of bone defects.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

The above and other objects, features and advantages of the present invention will become more apparent by describing in more detail exemplary embodiments thereof with reference to the attached drawings.

FIG. 1 shows the synthetic route of the components of the hydrogel scaffold of the present invention.

FIG. 2 shows a solution of carboxyethyl chitin grafted adipic acid dihydrazide (CECT-ADH).

FIG. 3 shows a carboxyethyl chitosan grafted dodecanal (CES-DOD) solution.

FIG. 4 shows a polyvinyl alcohol grafted benzaldehyde (PVA-BA) solution.

Fig. 5 is a mechanical strength picture of an injectable, self-healing hydrogel for bone repair.

Fig. 6 is a healing picture of an injectable, self-healing hydrogel for bone repair.

Fig. 7 is an injection picture of an injectable, self-healing hydrogel for bone repair.

Fig. 8 is an adhesion picture of an injectable, self-healing hydrogel for bone repair.

Fig. 9 is an in vivo degradation picture of an injectable, self-healing hydrogel for bone repair.

Detailed Description

Preferred embodiments of the present invention will be described in more detail below. While the preferred embodiments of the present invention are described below, it should be understood that the present invention may be embodied in various forms and should not be limited to the embodiments set forth herein.

Example 1

(1) Synthesis of carboxyethyl chitin grafted adipic acid dihydrazide (CECT-ADH)

The synthetic route for CECT-ADH is shown in FIG. 1 a. Carboxyethyl chitin (CECT, 1.50g,5.98 mmol) was dissolved in 300mL deionized water. Adipic acid dihydrazide (ADH, 2.08g,11.95 mmol), morpholinoethanesulfonic acid (MES, 639.8mg,30 mmol), 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride (EDC, 286.4mg,1.49 mmol) and N-hydroxysuccinimide (NHS, 171.9mg,1.49 mmol) were added to the above solution and the reaction was stirred at 25℃for 10 hours under dark conditions. The final product CECT-ADH is obtained after dialysis and freeze drying.

(2) Synthesis of carboxyethyl chitosan grafted dodecanal (CES-DOD)

The synthetic route for CES-DOD is shown in FIG. 1 b. MES (426.5 mg,20 mmol) and sodium cyanoborohydride (NaCNBH) ₃ 299.8mg,4.77 mmol) was introduced into 200mL of carboxyethyl chitosan solution (CES, 1.00g,4.85 mmol). Subsequently, dodecanal (DOD, 88.5mg,0.48 mmol) was dissolved in ethanol, and the solution was dropped under dark conditions at a dropping rate of 1mL/15min. The mixture is reacted for 24 hours at 25 ℃, then is put into a dialysis bag (MWCO 8 k) for dialysis on deionized water, and the CES-DOD product is obtained after freeze drying.

(3) Synthesis of polyvinyl alcohol grafted benzaldehyde (PVA-BA)

The synthetic route of PVA-BA is shown in figure 1 c, and the detailed steps are as follows: 4-hydroxybenzaldehyde (0.68 g,4.54 mmol) and 4-formylbenzoic acid (DMAP, 4.80g,40 mmol) as well as a catalytic amount of anhydrous pyridine were added to a solution of 100mL of polyvinyl alcohol (PVA, 1g,22.70 mmol) in dimethyl sulfoxide under nitrogen atmosphere, and succinic anhydride (2 g,22 mmol) was added after stirring at 80℃for 3 h. After reacting for 6 hours, cooling to room temperature, pouring into glacial ethyl ether for reprecipitation, collecting precipitate, redissolving in deionized water, filling into a dialysis bag (MWCO 8 k) for respectively dialyzing ethanol water solution and deionized water, and freeze-drying to obtain a product PVA-BA.

(4) Preparation of hydrogels

CECT-ADH, CES-DOD and PVA-BA were each dissolved in PBS buffer at ph=7.4. As shown in FIGS. 2-4, CECT-ADH, CES-DOD and PVA-BA were dissolved in PBS at room temperature to give a clear aqueous solution. PVA-BA was mixed with a solution containing CECT-ADH and CES-DOD in different molar ratios (R=M-NH) at a constant solids content of 5.0wt% ₂ M-CHO) were formulated to be 0, 0.2, 0.5, 0.8 and 1.0, respectively. Mixing CECT-ADH and CEC-DOD, adding PVA-BA solution, vortex mixing, transferring to polytetrafluoroethylene mould, and aging at 37deg.C for 60min to obtain CECT-ADH/PVA-BA/CES-DOD hydrogel. The composition of CPD0-4 gel is shown in Table 1.

TABLE 1 composition of the hydrogel components.

Test example 1 rheology analysis

Dynamic frequency scanning rheological test is adopted to examine the mechanical property of the hydrogel.

Specifically, a Discovery HR-2 rheometer (TA Instruments, USA) was used to measure the gel time and mechanical properties of the samples, and a 40mm diameter plate was used as the jig with a plate spacing of 1mm. Prior to the time and frequency sweep, a strain amplitude sweep is first performed to determine the linear viscoelastic region of the sample. During testing, silicone oil is coated on the edge of the sample to prevent water evaporation. The gel time of the hydrogels was assessed by time scanning with a fixed frequency of 1Hz and strain of 1.0%. The three precursor solutions were rapidly mixed and transferred to a jig, and then the change curves of storage modulus (G') and loss modulus (G ") with time at 37 ℃ were recorded to examine the mechanical properties of the hydrogels.

As shown in FIG. 5, when [ M-NH ] ₂ :M-CHO]When the molar ratio of 0 is increased to 1.0, the G' of the CPD hydrogel is obviously reduced from 15.18+/-0.52 kPa to 2.11+/-0.77 kPa, at the moment, the CES-DOD and corresponding Schiff base bond concentration are increased, the CECT-ADH and corresponding acylhydrazone bond concentration are reduced, and the stability of the hydrogel network is poor and the strength is reduced due to the increase of the Schiff base bond concentration.

Test example 2 self-healing and injectability evaluation

The self-healing capacity of hydrogel CPD2 was evaluated by macroscopic visualization, respectively. First, the heart-shaped hydrogels stained with rhodamine B and methyl blue, respectively, were each cut in half. Then two heart-shaped hydrogel sheets with different colors are attached together along the tangential plane, put into the original mould, put into a drier with higher humidity, healed at 37 ℃, and record the self-healing process of the hydrogel by a digital camera. In addition, hydrogel CPD2 was prepared in situ in a 21G syringe, and the syringe was used to write the "WHU" in a petri dish.

As shown in fig. 6, two hydrogel sheets, each stained with rhodamine B and methyl blue, were each cut in half; then two heart-shaped hydrogel sheets with different colors are attached together, and the hydrogel begins to fuse after healing for 0.5h at 37 ℃; after 2 hours of healing, the two heart-shaped hydrogel sheets are healed into a complete hydrogel sheet, and after 7 hours of healing, the cutting trace is completely disappeared. It can be seen that during the repair process, the two dye molecules continuously diffuse towards the cut surface and eventually fuse to purple at the cut surface. The results show that the hydrogel can effectively realize self-healing.

As shown in FIG. 7, the methyl blue-stained CECT-ADH solution, CES-DOD solution and PVA-BA solution were rapidly and uniformly mixed in a centrifuge tube and then put into a syringe barrel to be cured at 37℃for 0.5h. After the plunger of the syringe is pressed at room temperature, the gel in the syringe is easily extruded through a thin needle (21G), and finally, the complete hydrogel is quickly formed in situ, so that the excellent injection performance of the chitin/chitosan composite hydrogel is verified.

Test example 3 adhesion test

And evaluating the adhesion strength of the hydrogel to the surfaces of various materials by using an adhesion experiment. The method comprises the following steps: the components of the hydrogel solution are rapidly mixed according to a proportion and then are dripped on the surface of the pigskin to form the hydrogel in situ, the hydrogel is stretched, twisted and bent after standing for 30min at 37 ℃, the surface of the hydrogel is rapidly washed by water, and the adhesiveness of the hydrogel to fresh pigskin is tested. In addition, the above procedure was repeated, and the adhesion strength of the hydrogel to materials such as heart, kidney, lung, spleen, liver, steel plate, wood plate, rubber, glass, plastic, etc. was measured.

As shown in fig. 8, in order to vividly demonstrate the adhesion performance of CPD2, images were obtained in which CPD2 was adhered to various surfaces of steel plates, wood plates, rubber, glass and plastic solid materials, and skin, heart, liver, spleen, lung, kidney biological tissues, etc. As can be seen from the figure, the hydrogel is firmly adhered to the surface of the pig skin after the pig skin adhered by the CPD2 is stretched, twisted, bent and washed with water, and the result shows that the hydrogel can be applied to adhesion in-vivo wet and dynamic environments. The mechanism of adhesion of chitin/chitosan composite hydrogels is due to amino and dodecyl groups on natural polysaccharides, which have been shown to be capable of intercalating into the bilayer of cell membranes for immobilization.

Test example 4 degradation Properties in vivo

The in vivo degradation performance of the hydrogels was evaluated using 18 BALB/C mice, the mice were anesthetized first with sodium pentobarbital, then 400 μl of the in situ formed hydrogels were injected subcutaneously into the backs of the mice using a syringe, three mice were sacrificed 5 minutes, 2 weeks, 4 weeks, 6 weeks, 8 weeks after injection, respectively, using an excessive anesthetic method, the skin of the backs of the mice was exposed using an ophthalmic scissors, and the hydrogels were photographed using a camera to evaluate the degradation of the hydrogels in vivo.

As shown in fig. 9, the hydrogel was injected subcutaneously into mice, and the complete hydrogel was observed immediately after injection. CPD0 and CPD4 substantially disappeared at week 4 and week 6, respectively, after injection, while CPD2 remained at around 24.4% at week 8 after injection. Thus, a modest degradation rate provides adequate time for the new bone to gradually replace the degraded hydrogel scaffold. And there is no obvious redness of the skin tissue around the injection site, which is related to the good biocompatibility of hydrogels. Therefore, the chitin/chitosan composite hydrogel has ideal in vivo degradation performance and can be used for bone defect repair experiments.

The foregoing description of embodiments of the invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the various embodiments described.

Claims (10)

1. A method for preparing injectable, self-healing hydrogel for bone repair, comprising the steps of:

(1) Synthesizing carboxyethyl chitin grafted adipic acid dihydrazide CECT-ADH;

dissolving carboxyethyl chitin in deionized water, adding adipic dihydrazide, morpholinoethanesulfonic acid, 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide into the solution, stirring the solution in a dark place for reaction, and obtaining a product CECT-ADH after dialysis and freeze drying;

(2) Synthesizing carboxyl ethyl chitosan grafted dodecanal CES-DOD;

introducing morpholine ethanesulfonic acid and sodium cyanoborohydride into a carboxyethyl chitosan solution, then dissolving dodecanal into ethanol, dripping into the solution under the condition of avoiding light, reacting the obtained mixture, dialyzing and freeze-drying to obtain a product CES-DOD;

(3) Synthesizing polyvinyl alcohol grafted benzaldehyde PVA-BA;

under the nitrogen atmosphere, adding 4-hydroxybenzaldehyde, 4-formylbenzoic acid and catalytic amount of anhydrous pyridine into a polyvinyl alcohol dimethyl sulfoxide solution, heating and stirring for reaction, adding succinic anhydride, cooling to room temperature after continuing the reaction, pouring into glacial ethyl ether for reprecipitation, and obtaining a product PVA-BA through redissolution, dialysis and freeze drying;

(4) Preparing hydrogel;

and respectively dissolving CECT-ADH, CES-DOD and PVA-BA in PBS buffer solution, then uniformly mixing CECT-ADH solution and CEC-DOD solution, then adding PVA-BA solution, rapidly and uniformly mixing the obtained mixed solution by vortex, transferring the mixed solution into a polytetrafluoroethylene mould, and curing to obtain the CECT-ADH/PVA-BA/CES-DOD hydrogel.

2. The production method according to claim 1, wherein in the step (1), the molar ratio of the carboxyethyl chitin, adipic acid dihydrazide, morpholinoethanesulfonic acid, 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide is 1:1.8-2.2:4.5-5.5:02-0.3:02-0.3.

3. The preparation method according to claim 1, wherein in the step (1), the temperature of the light-shielding stirring reaction is 20-30 ℃ for 6-36h.

4. The preparation method according to claim 1, wherein in the step (2), the molar ratio of the dodecanal, the morpholinoethanesulfonic acid, the sodium cyanoborohydride and the carboxyethyl chitosan is 1:40-45:8-12:8-12.

5. The preparation method according to claim 1, wherein in the step (2), the dropping speed of the dodecanol solution is 1mL/30min-1mL/min, the reaction temperature is 20-30 ℃ and the reaction time is 12-48h.

6. The production method according to claim 1, wherein in the step (3), the molar ratio of 4-hydroxybenzaldehyde, 4-formylbenzoic acid, polyvinyl alcohol and succinic anhydride is 1:6-10:4-6:4-6.

7. The preparation method according to claim 1, wherein in the step (3), the heating reaction is carried out at a temperature of 75-85 ℃ for a time of 2-4 hours;

the reaction is continued for 2-10h after the succinic anhydride is added.

8. The process according to claim 1, wherein in step (4), the pH of the PBS buffer is 7.2 to 7.6;

mixing the PVA-BA solution with the CECT-ADH solution and the CES-DOD solution so that the amino/aldehyde ratio in the mixture is 1.0-3.0;

mixing the PVA-BA solution with the CECT-ADH solution and the CES-DOD solution so that the solid content of the mixture is 1.0-5.0wt%; preferably, the PVA-BA solution has a concentration of 1.0-5.0wt%, the CECT-ADH solution has a concentration of 1.0-5.0wt%, and the CES-DOD solution has a concentration of 1.0-5.0wt%;

the curing temperature is 37 ℃ and the curing time is 10min-120min.

9. A hydrogel produced by the production method according to any one of claims 1 to 8.

10. Use of the hydrogel of claim 9 for the preparation of a bone repair material.

Images