Antibacterial conductive skeletal muscle repair hydrogel scaffold as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of medical materials, and particularly relates to an antibacterial conductive skeletal muscle repair hydrogel stent as well as a preparation method and application thereof. The antibacterial conductive skeletal muscle repair hydrogel scaffold is prepared by dispersing polylysine-modified polyvinyl alcohol, aldehyde dextran and multi-walled carbon nanotubes in a boric acid solution, carrying out nucleophilic addition reaction on aldehyde groups in the aldehyde dextran and amino groups of the polylysine-modified polyvinyl alcohol to form imine bonds so as to obtain a dynamic Schiff base structure, and carrying out ultrasonic dispersion on the dynamic Schiff base structure so as to obtain the antibacterial conductive skeletal muscle repair hydrogel scaffold. Hydroxyl in the polylysine modified polyvinyl alcohol reacts with boric acid to form boric acid ester bonds for crosslinking. The antibacterial conductive skeletal muscle repairing hydrogel stent is high in forming speed, can quickly form gel within only 5 seconds, and has super-strong stretchability elongation gt; the shape adaptability gt is excellent; 99% of shape recovery and rapid self-healing ability lt; 10s.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of medical materials, and particularly relates to an antibacterial conductive skeletal muscle repair hydrogel scaffold and a preparation method and application thereof. BACKGROUND

[0002] Skeletal muscle accounts for about 40% to 50% of body weight and has important functions in controlling force generation, movement and protection of internal organs. Skeletal muscle injury caused by accidental trauma, exercise, disease and surgery is increasing. Skeletal muscle with slight injury can repair itself, but severe lesions or volume loss can cause local depression, atrophy, and even motor disorders and loss of physiological function.

[0003] In addition to etiological treatment and functional exercise, the traditional scheme for treating severe skeletal muscle injury is muscle flap or muscle transplantation, but transplantation surgery is limited by the limited source of donors, high risk of infection and low survival rate of transplants, resulting in poor prognosis. In order to cope with these clinical challenges, researchers propose to solve severe skeletal muscle injury by skeletal muscle tissue engineering. Skeletal muscle tissue engineering usually involves implanting a tissue engineering scaffold into the lesion site to induce endogenous cells to differentiate into myoblasts and integrate with the host skeletal muscle tissue, thereby achieving repair and reconstruction of skeletal muscle. In recent years, hydrogel scaffolds have been widely used in skeletal muscle tissue engineering and have achieved good therapeutic effects due to their unique three-dimensional network structure and physical and chemical properties, which simulate the extracellular matrix and promote the exchange and transport of various nutrients. However, most existing scaffolds are prepared from a single natural polysaccharide or artificial synthetic polymer, lack good antibacterial properties and conductive properties similar to muscle tissue, and have a long preparation time, making it difficult to meet the dynamic physiological load of skeletal muscle, which severely limits the application of the scaffold in skeletal muscle tissue engineering. SUMMARY

[0004] To solve the above technical problems, the present application provides an antibacterial conductive skeletal muscle repair hydrogel scaffold and a preparation method and application thereof.

[0005] The technical solution of the present application is as follows.

[0006] The present application provides an antibacterial conductive skeletal muscle repair hydrogel scaffold prepared by the following method. Polylysine-modified polyvinyl alcohol, aldehyde-modified dextran and carbon nanotubes are dispersed in a boric acid solution, the aldehyde group in the aldehyde-modified dextran reacts with the amino group of the polylysine-modified polyvinyl alcohol to form an imine bond, obtaining a dynamic Schiff base structure; the carbon nanotubes react with the hydroxyl groups of the polylysine-modified polyvinyl alcohol and the aldehyde-modified dextran to form hydrogen bonds; the hydroxyl groups in the polylysine-modified polyvinyl alcohol react with boric acid to form a borate ester bond, obtaining the antibacterial conductive skeletal muscle repair hydrogel scaffold; The crosslinking gelation time is 5s-30s.

[0007] The present application forms an imine bond through the nucleophilic addition reaction between the aldehyde group in the aldehyde-modified dextran and the amino group of the polylysine-modified polyvinyl alcohol, which is fast, so that the hydrogel can quickly form a network structure, and the dynamic Schiff base structure obtained enables the hydrogel to realize self-repairing by re-forming the imine bond after damage; the polylysine-modified polyvinyl alcohol has good flexibility, and the formation of the imine bond enables the network structure to have a certain elasticity, which helps to improve the stretchability of the hydrogel; the boronic acid reacts with the hydroxyl groups in the polylysine-modified polyvinyl alcohol and the aldehyde-modified dextran to quickly form a borate ester bond, further crosslinking the hydrogel network and promoting rapid gelation. In addition, the carbon nanotubes react with the hydroxyl groups in the polylysine-modified polyvinyl alcohol and the aldehyde-modified dextran to form hydrogen bonds, further improving the mechanical properties and electrical conductivity of the hydrogel. Under the crosslinking action of the dynamic chemical bonds of the Schiff base and the borate ester bond, the preparation time of the hydrogel is significantly shortened, the shape adaptability and healing ability of the hydrogel are enhanced, and the stability of the hydrogel is effectively improved.

[0008] In another preferred embodiment, the aldehyde-modified dextran is obtained by oxidizing dextran under the action of periodic acid.

[0009] In another preferred embodiment, the polylysine-modified polyvinyl alcohol is obtained by esterifying polyvinyl alcohol with methacrylic anhydride to obtain methacrylated polyvinyl alcohol, and grafting polylysine onto the methacrylated polyvinyl alcohol through Michael addition reaction under the action of a catalyst.

[0010] The second aspect of the present application provides a preparation method of the antibacterial conductive skeletal muscle repair hydrogel scaffold, comprising the following steps: esterifying polyvinyl alcohol with methacrylic anhydride in an aqueous environment to obtain methacrylated polyvinyl alcohol; grafting polylysine onto the methacrylated polyvinyl alcohol through Michael addition reaction under the action of a catalyst to obtain polylysine-modified polyvinyl alcohol; oxidizing the hydroxyl groups of dextran to aldehyde groups through oxidation reaction in an aqueous environment under light-free environment to obtain aldehyde-modified dextran; dispersing the polylysine-modified polyvinyl alcohol, the aldehyde-modified dextran and the carbon nanotubes in a boric acid solution to obtain the antibacterial conductive skeletal muscle repair hydrogel scaffold; The mass percentage of the boric acid solution is 2%-2.5%; when the mass percentage of boric acid is <2%, B(OH)4 -Deficiency, unable to form enough reversible boron ester bond with polyvinyl alcohol, low gel strength, poor shape memory; when the mass percentage is >2.5%, B(OH)4 - Excess, easy to form permanent cross-linking with polyvinyl alcohol hydroxyl, network is too dense, elongation decreases sharply.

[0011] The mass ratio of polylysine modified polyvinyl alcohol, aldehyde-based dextran, carbon nanotube and boric acid solution is 5-4:1-2:1-3:2.

[0012] In another preferred embodiment, the molar ratio of the methacrylic anhydride to the polyvinyl alcohol is 0.5-2:1; The esterification reaction temperature is 60-70 DEG C, and the reaction time is 24-48 h. The esterification reaction temperature of 60-70 DEG C is lower than the thermal degradation temperature of polyvinyl alcohol, which can ensure the sufficient diffusion of methacrylic anhydride and avoid the main chain breakage, so that the integrity of the polyvinyl alcohol main chain is maintained to provide an elastic skeleton for ultrahigh tensile property. The reaction time of 24-48 h can prevent excessive cross-linking and brittle, and ensure enough sites for subsequent Michael addition reaction.

[0013] In another preferred embodiment, the molar ratio of the polylysine to the methacrylated polyvinyl alcohol is 0.5-2:1; The Michael addition reaction temperature is 60-70 DEG C, and the reaction time is 48-72 h. The Michael addition reaction can be maintained at high efficiency at 60-70 DEG C, and the grafting length and grafting density can be ensured at 48-72 h.

[0014] In another preferred embodiment, the catalyst is potassium carbonate or cesium carbonate, and the molar ratio of the catalyst to the polylysine is 0.5-3:1.

[0015] In another preferred embodiment, the molar ratio of the sodium periodate to the dextran is 0.5-3:1; The oxidation reaction temperature is 30-50 DEG C, and the stirring reaction time is 24-48 h. The activity of periodate can be maintained at 30-50 DEG C, and the main chain breakage of dextran caused by excessive oxidation can be avoided; the hydroxyl group can be converted into enough aldehyde group at 24-48 h, and the dynamic imine bond density can be improved by the sufficient aldehyde group, which can be quickly recombined and healed within <10 s.

[0016] The third aspect of the application provides application of the antibacterial conductive skeletal muscle repair hydrogel scaffold in preparation of a product for promoting myogenic differentiation and healing of infected skeletal muscle defects.

[0017] Compared with the prior art, the application has the following beneficial effects: The antibacterial conductive skeletal muscle repair hydrogel scaffold in the application is prepared by the nucleophilic addition reaction of the aldehyde group in the aldehyde-modified dextran and the amino group of the polylysine-modified polyvinyl alcohol to form an imine bond, and the obtained dynamic Schiff base structure, the reaction speed is fast, and the gelation time is shortened; the boronic acid reacts with the hydroxyl groups in the polylysine-modified polyvinyl alcohol and the aldehyde-modified dextran to quickly form a borate ester bond, further crosslink the hydrogel network, promote rapid gelation, and the whole process only needs 5 seconds for rapid gelation. The polylysine-modified polyvinyl alcohol has good flexibility, the formation of the imine bond makes the network structure have a certain elasticity, which helps to improve the stretchability of the hydrogel, so that the stretchability elongation of the antibacterial conductive skeletal muscle repair hydrogel scaffold is greater than 4000 %, and the shape adaptability is strong, and the shape recovery is greater than 99 %; the dynamic Schiff base structure enables the hydrogel to realize self-repairing by re-forming the imine bond after being damaged, and the self-healing speed is less than 10 s; the carbon nanotubes also react with the hydroxyl groups in the polylysine-modified polyvinyl alcohol and the aldehyde-modified dextran to form hydrogen bonds, further improving the mechanical property and the conductive property of the hydrogel. And the antibacterial conductive skeletal muscle repair hydrogel scaffold in the application has good degradability and injectability, and is degraded by 98 % after about 20 days in a simulated body fluid environment. The scaffold has good cell compatibility, antioxidant, anti-inflammatory and myogenic differentiation promoting biological functions, and exhibits excellent antibacterial properties against gram-positive bacteria Staphylococcus aureus and gram-negative bacteria Escherichia coli under the action of chemical antibacterial peptides and physical near-infrared light.

[0018] The antibacterial conductive skeletal muscle repair hydrogel scaffold prepared by the method in the application has the advantages of simple preparation method, convenient use, natural and environment-friendly raw materials, and low cost. The hydrogel scaffold is rapidly gelled in 5 seconds, and has good physicochemical properties and biological properties. In a Staphylococcus aureus infection model of a rat tibialis anterior muscle volume defect, the hydrogel scaffold well adapts to the shape of the defect site and the dynamic mechanical environment of the skeletal muscle, and exhibits outstanding repair-promoting effect and antibacterial activity. The hydrogel scaffold provides a new type of scaffold for skeletal muscle tissue engineering. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The OEDX and PVA-EPL synthesized in the application 1 H-NMR spectrum, wherein A is the H-NMR spectrum of OEDX 1 H-NMR spectrum, B is the H-NMR spectrum of PVA-EPL 1 H-NMR spectrum; OEDX is aldehyde-modified dextran, and PVA-EPL is polylysine-modified polyvinyl alcohol.

[0020] Figure 2The bacteriostatic effect diagram of the antibacterial conductive skeletal muscle repair hydrogel scaffold prepared in the application; wherein, A is the antibacterial result diagram of E. coli, and B is the antibacterial result diagram of Staphylococcus aureus; in the diagram, Blank represents a blank group without the hydrogel; PEO represents a hydrogel group without carbon nanotubes; PEOCL is a hydrogel group with low-concentration carbon nanotubes; and PEOCH is a hydrogel group with high-concentration carbon nanotubes.

[0021] Figure 3 The result diagram of cytotoxicity determination and compatibility determination of the antibacterial conductive skeletal muscle repair hydrogel scaffold prepared in the application; wherein, A is the result diagram of cytotoxicity determination on mouse muscle cells, and B is the result diagram of blood compatibility determination on mice; in the diagram, Triton is Triton X-100, which is a reagent for destroying the membrane of cells and is used as a positive control for complete rupture of blood cells in a hemolysis experiment.

[0022] Figure 4 The in-vitro myogenic differentiation promoting effect of the antibacterial conductive skeletal muscle repair hydrogel scaffold prepared in the application; A is the result diagram of myosin heavy chain protein differentiation, B is the result diagram of cell nucleus differentiation, and C is a combined diagram of A and B.

[0023] Figure 5 The in-vivo effect of the antibacterial conductive skeletal muscle repair hydrogel scaffold prepared in the application on promoting infected skeletal muscle repair and regeneration; in the diagram, Normal is a normal group, Blank represents a blank control group, and PEOCH+NIR represents a hydrogel group under near-infrared light irradiation. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0025] It should be noted that the professional terms used in the application are only for the purpose of describing the specific embodiments, and are not intended to limit the protection scope of the application. Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the following embodiments of the application can be purchased from the market or prepared by the existing method.

[0026] Hydrogel scaffolds have been widely used in skeletal muscle tissue engineering and have achieved good therapeutic effect. The three-dimensional network structure and physical and chemical properties of hydrogels can simulate the extracellular matrix, promote the exchange and transport of nutrients. However, the existing skeletal muscle tissue engineering scaffolds lack antibacterial properties, and the mechanical properties such as elasticity, stretchability and ductility are not ideal, and the gelation period is long, which is ten minutes to several days, resulting in low skeletal muscle tissue reconstruction efficiency. Therefore, constructing a multifunctional hydrogel scaffold is the key to promoting skeletal muscle repair. The hydrogel scaffold should have excellent elasticity and tensile mechanical properties, good shape adaptability to meet various irregular muscle defects; fast gelation period, injectability and self-healing to facilitate use; good electrical conductivity to facilitate information transmission between cells; excellent antibacterial properties to effectively reduce the risk of infection; adjustable degradation to ensure seamless integration with newly formed tissues and no need for second surgery.

[0027] Therefore, based on aldehyde-based dextran (ODEX), polylysine-modified polyvinyl alcohol (PVA-EPL), multi-walled carbon nanotubes (MWCNTs) and boric acid solution, a fast-gelling, highly stretchable, shape-adaptable, degradable, self-healing and conductive hydrogel scaffold is prepared by dynamic Schiff base and borate bond crosslinking. The hydrogel scaffold shows good biocompatibility, antibacterial property and antioxidant property in vitro and in vivo, and also shows good effect of promoting skeletal muscle repair and reconstruction in an infected skeletal muscle defect model, which is a super-stretching fast-crosslinking antibacterial conductive hydrogel scaffold for skeletal muscle repair.

[0028] The application provides an antibacterial conductive skeletal muscle repair hydrogel scaffold and a preparation method and application thereof, which comprises the following steps: 1) First, dextran is added to ultrapure water, and stirred and dissolved at room temperature, then sodium periodate is added, and the molar ratio of dextran to sodium periodate is 1:(0.5-2). Then the reaction temperature is increased to 40-50 °C and stirred for 6-24 hours. After the reaction is completed, ethylene glycol is added and stirred for 2 hours to terminate the oxidation reaction. Then the reaction liquid is placed in a dialysis bag (MWCO12000) for dialysis purification for 3-5 days, and finally ODEX powder is obtained by vacuum freeze-drying.

[0029] 2) Polyvinyl alcohol is added to ultrapure water, and stirred and dissolved at 60-70 °C, then methacrylic anhydride is added, and the molar ratio of polyvinyl alcohol to methacrylic anhydride is 1:(0.5-2). Then avoid light reaction for 24-48 hours, after the reaction is completed, the reaction liquid is placed in a dialysis bag (MWCO12000) for dialysis purification for 3-5 days, and finally a PVAMA solution is obtained by rotary evaporation concentration.

[0030] 3) The pH of the PVAMA solution is adjusted to 8.0, then the polypeptide epsilon-polylysine and potassium carbonate are added to the PVAMA solution, and the reaction is carried out at 60-70 °C for 24-72 hours. After the reaction is completed, the reaction solution is placed in a dialysis bag (MWCO 12000) for dialysis purification for three to five days, and finally PVA-EPL powder is obtained by vacuum freeze-drying.

[0031] 4) The obtained OEDX is dissolved in ultrapure water to prepare a solution with a mass fraction of 5%-10%, the PVA-EPL is dissolved in ultrapure water to prepare a solution with a mass fraction of 20%-30%, the boric acid is dissolved in ultrapure water to prepare a solution with a mass fraction of 1%-2%, and the MWCNTs are ultrasonically dispersed in ultrapure water at a concentration of 1 mg / mL-2 mg / mL. The PVA-EPL, OEDX, MWCNTs and boric acid solutions are quickly mixed in a volume ratio of (4-5):(1-2):(1-3):2 to obtain a super-tensile and fast-crosslinking antibacterial conductive skeletal muscle repair hydrogel scaffold.

[0032] The structural formula of the polymer is as follows.

[0033] OEDX: ; wherein x has a value in the range of 1-60, and y has a value in the range of 60-100.

[0034] PVAMA: ; wherein n has a value in the range of 278-556.

[0035] PVA-EPL: ; wherein n1 has a value in the range of 1-278, n2 has a value in the range of 278-556, and n3 has a value in the range of 1-556.

[0036] In order to better understand the present application, the present application will be described in detail below in conjunction with specific embodiments, but the content of the present application is not limited only to the following examples.

[0037] The dialysis bag described below is a MWCO12000 model purchased from Shanghai Yuan Ye Biological Technology Co., Ltd.; sodium periodate, methacrylic anhydride, polypeptide epsilon-polylysine, polyvinyl alcohol and dextran are all purchased from Anjie Chemical Reagent Co., Ltd.

[0038] Example 1 A preparation method of an antibacterial conductive skeletal muscle repair hydrogel scaffold, comprising the following steps: S1, first add dextran into ultrapure water, stir to dissolve at room temperature, then add sodium periodate, and the molar ratio of dextran and sodium periodate is 1:0.5, after stirring at 40°C for 6h, add ethylene glycol and stir for 2h to terminate the oxidation reaction, then put into dialysis bag for dialysis purification for three to five days, finally get ODEX powder by vacuum freeze-drying for further use; the structure of ODEX is as follows: wherein x is 50 and y is 60.

[0039] S2, the preparation method of PVAMA polymer: add polyvinyl alcohol into ultrapure water, stir to dissolve at 60°C, then add methacrylic anhydride, and the molar ratio of polyvinyl alcohol and methacrylic anhydride is 1:0.5. Then avoid light reaction for 24 hours, after the reaction is completed, put the reaction solution into dialysis bag for dialysis purification for 3 days, finally concentrate to 70% of the original volume by rotary evaporation to obtain PVAMA solution. The structure of PVAMA is as follows: ; wherein n is 300.

[0040] S3, adjust the pH value of the PVAMA solution to 8, then add 0.43g of polypeptide ε-polylysine and 0.012g of potassium carbonate into the PVAMA solution, react at 60°C for 24h, after the reaction is completed, put into dialysis bag for dialysis purification for 3 days, finally get PVA-EPL powder by vacuum freeze-drying; the structure of PVA-EPL is as follows: ; wherein n1 is 278, n2 is 300 and n3 is 100.

[0041] S4, dissolve the obtained OEDX in ultrapure water to prepare a solution with a mass fraction of 5%, dissolve PVA-EPL in ultrapure water to prepare a solution with a mass fraction of 20%, dissolve boric acid in ultrapure water to prepare a solution with a mass fraction of 1%, ultrasonically disperse MWCNTs in ultrapure water at a concentration of 1mg / mL, quickly mix the PVA-EPL, OEDX, MWCNTs and boric acid solutions according to the volume ratio of 4:2:3:2 to obtain a super-stretching and fast-crosslinking antibacterial and conductive skeletal muscle repair hydrogel scaffold.

[0042] The prepared antibacterial and conductive skeletal muscle repair hydrogel scaffold is characterized, and the results are shown in Figure 1 As can be seen from A in Figure 1 , the multiple peaks of hydroxyl group are respectively located at 5.6ppm, 4.8ppm and 3.4ppm~4.0ppm, which belong to dextran, the chemical shift of hydrogen in aldehyde is close to 5.1ppm, indicating that the hydroxyl group is oxidized, the appearance of these peaks indicates that ODEX is successfully synthesized. In addition, Figure 1In Figure B, the peaks at 1.2ppm, 1.4ppm and 1.7ppm are the methylene peaks (-CH2) of the polypeptide ε-polylysine. The appearance of this result indicates that the polypeptide ε-polylysine has been successfully grafted onto PVAMA and a new PVA-EPL polymer has been formed.

[0043] The antibacterial conductive skeletal muscle repair hydrogel scaffold prepared above was subjected to antibacterial experiments, using a blank group (no hydrogel added), a hydrogel group without carbon nanotubes, a hydrogel group with low carbon nanotube concentration, and a hydrogel group with high carbon nanotube concentration. The carbon nanotube concentration in the low carbon nanotube hydrogel group was 0.5 mg / mL, and the carbon nanotube concentration in the high carbon nanotube hydrogel group was 1 mg / mL. The specific results are shown below. Figure 2 As shown. Figure 2 The results show that the hydrogel groups without carbon nanotubes, low carbon nanotube concentrations, and high carbon nanotube concentrations all exhibited good antibacterial effects, with the high-carbon nanotube concentration group showing the best antibacterial effect, achieving a 99% kill rate against Escherichia coli and Staphylococcus aureus. Furthermore, with the assistance of near-infrared light, the kill rate reached 99.99%, demonstrating that the antibacterial conductive skeletal muscle repair hydrogel scaffold of the present invention possesses excellent broad-spectrum antibacterial properties. The PVA-EPL synthesis process did not destroy the antibacterial ability of the ε-polylysine polypeptide.

[0044] The antibacterial conductive skeletal muscle repair hydrogel scaffold prepared above was subjected to a bone repair experiment, as follows: Figure 3 Antibacterial and electrically conductive hydrogel scaffolds for skeletal muscle repair for mouse myoblasts (C2C12, Figure 3 A) and mouse red blood cells ( Figure 3 Cytotoxicity and hemolysis rate determination in B) It can be seen that the antibacterial conductive skeletal muscle repair hydrogel scaffold of the present invention has good biocompatibility.

[0045] Figure 4 In vitro myogenic differentiation results of hydrogel scaffolds for antimicrobial and electrically conductive skeletal muscle repair. Figure 4 The red light in A represents myosin heavy chain protein. Figure 4 The blue light in B represents the cell nucleus. Figure 4 The C in Figure 4 It can be seen that the scaffold can significantly promote myogenic differentiation. These results can prove that the antibacterial conductive skeletal muscle repair hydrogel scaffold of the present invention can be used as a skeletal muscle repair material.

[0046] Figure 5In vivo biological results of the antibacterial conductive skeletal muscle repair hydrogel scaffold. The tissue macroscopic pictures of the 7th day, 14th day and 28th day after the scaffold was transplanted into the defect site at the site of the rat tibialis anterior muscle defect (5mm x 3mm x 2mm) injected with Staphylococcus aureus bacterial solution. At the 7th day, compared with the normal group, the other four groups all had different degrees of infection, and the defect was obvious, and the blank group had the most serious infection, and the hydrogel group had lighter infection under the action of double antibacterial. At 14 days, the infection of the blank group was reduced, and the hydrogel group had almost no infection, and the defect began to repair rapidly, and at 28 days, the blank group still had obvious defect, while the hydrogel group under near-infrared light had almost complete repair of the defect. These results show that the antibacterial conductive skeletal muscle repair hydrogel scaffold can be used for skeletal muscle repair.

[0047] Example 2 A method for preparing an antibacterial conductive skeletal muscle repair hydrogel scaffold, comprising the following steps: S1, add dextran into ultrapure water, stir to dissolve at room temperature, then add sodium periodate, and the molar ratio of dextran and sodium periodate is 1:1. Then increase the reaction temperature to 45ºC and stir for 12 hours. After the reaction is completed, add ethylene glycol and stir for 2 hours to terminate the oxidation reaction. Then put the reaction solution into a dialysis bag for 4 days of dialysis purification, and finally obtain ODEX powder by vacuum freeze-drying; the structure of ODEX is as follows:

[0048] Wherein x is 40 and y is 70.

[0049] S2, add polyvinyl alcohol into ultrapure water, stir to dissolve at 65ºC, then add methacrylic anhydride, and the molar ratio of polyvinyl alcohol and methacrylic anhydride is 1:1. Then avoid light for 36 hours, after the reaction is completed, put the reaction solution into a dialysis bag for 4 days of dialysis purification, and finally obtain PVAMA solution by rotary evaporation concentration; PVAMA: ; wherein n is 400.

[0050] S3, adjust the pH value of the PVAMA solution to 8, then add 0.86g of polypeptide ε-polylysine and 0.024g of potassium carbonate into the PVAMA solution, react at 60ºC for 24 hours, after the reaction is completed, put the reaction solution into a dialysis bag for 4 days of dialysis purification, and finally obtain PVA-EPL powder by vacuum freeze-drying; the structure of PVA-EPL is as follows: ; wherein n1 is 200, n2 is 400, and n3 is 200.

[0051] S4, the obtained OEDX is dissolved in ultrapure water to prepare a solution with a mass fraction of 10%, PVA-EPL is dissolved in ultrapure water to prepare a solution with a mass fraction of 25%, boric acid is dissolved in ultrapure water to prepare a solution with a mass fraction of 1.5%, and MWCNTs are ultrasonically dispersed in ultrapure water at a concentration of 1 mg / mL. The PVA-EPL, OEDX, MWCNTs and boric acid solutions are quickly mixed in a volume ratio of 4.5:1.5:1.5:2 to obtain a super-stretching and fast-crosslinking antibacterial and conductive skeletal muscle repair hydrogel scaffold.

[0052] Example 3 A method for preparing an antibacterial and conductive skeletal muscle repair hydrogel scaffold, comprising the following steps: S1, first, dextran is added to ultrapure water, and the dextran is dissolved by stirring at room temperature. Then, sodium periodate is added, and the molar ratio of dextran to sodium periodate is 1:1.5. Subsequently, the reaction temperature is increased to 50 ºC and stirring is performed for 18 hours. After the reaction is completed, ethylene glycol is added and stirred for 2 hours to terminate the oxidation reaction. Then, the reaction solution is placed in a dialysis bag for dialysis purification for 5 days, and finally ODEX powder is obtained by vacuum freeze-drying; the structure of ODEX is as follows:

[0053] wherein x is 30 and y is 80.

[0054] S2, polyvinyl alcohol is added to ultrapure water, and the polyvinyl alcohol is dissolved by stirring at 70 ºC. Then, methacrylic anhydride is added, and the molar ratio of polyvinyl alcohol to methacrylic anhydride is 1:1.5. Then, the reaction is carried out in the dark for 36 hours. After the reaction is completed, the reaction solution is placed in a dialysis bag for dialysis purification for 5 days, and finally a PVAMA solution is obtained by rotary evaporation; PVAMA: ; wherein n is 450.

[0055] S3, the pH value of the PVAMA solution is adjusted to 8.0. Then, 1.02 g of polypeptide ε-polylysine and 0.048 g of potassium carbonate are added to the PVAMA solution, and the reaction is carried out at 70 ºC for 48 hours. After the reaction is completed, the reaction solution is placed in a dialysis bag for dialysis purification for 5 days, and finally PVA-EPL powder is obtained by vacuum freeze-drying; the structure of PVA-EPL is as follows: ; wherein n1 is 150, n2 is 450, and n3 is 300.

[0056] S4, the obtained OEDX is dissolved in ultrapure water to prepare a solution with a mass fraction of 10%, PVA-EPL is dissolved in ultrapure water to prepare a solution with a mass fraction of 30%, boric acid is dissolved in ultrapure water to prepare a solution with a mass fraction of 1.5%, and MWCNTs are ultrasonically dispersed in ultrapure water at a concentration of 1 mg / mL. The PVA-EPL, OEDX, MWCNTs and boric acid solutions are quickly mixed in a volume ratio of 5:2:2:2 to obtain a super-strong tensile and fast-crosslinked antibacterial conductive skeletal muscle repair hydrogel scaffold.

[0057] Example 4 A method for preparing an antibacterial conductive skeletal muscle repair hydrogel scaffold, comprising the following steps: S1, dextran is added to ultrapure water, stirred and dissolved at room temperature, then sodium periodate is added, and the molar ratio of dextran to sodium periodate is 1:2. Then the reaction temperature is increased to 50 ºC and stirred for 24 hours. After the reaction is completed, add ethylene glycol and stir for 2 hours to terminate the oxidation reaction. Then the reaction liquid is placed in a dialysis bag for dialysis purification for three to five days, and finally vacuum freeze-dried to obtain ODEX powder for further use; the structure of ODEX is as follows:

[0058] wherein x is 20 and y is 90.

[0059] S2, polyvinyl alcohol is added to ultrapure water, stirred and dissolved at 70°C, then methacrylic anhydride is added, and the molar ratio of polyvinyl alcohol to methacrylic anhydride is 1:2. Then avoid light reaction for 48 hours, after the reaction is completed, the reaction liquid is placed in a dialysis bag for dialysis purification for three to five days, and finally concentrated by rotary evaporation to obtain a PVAMA solution for further use; PVAMA: ; wherein n is 500.

[0060] S3, the pH value of the PVAMA solution is adjusted to 8.0, then 2.04 g of polypeptide ε-polylysine and 0.096 g of potassium carbonate are added to the PVAMA solution, and the reaction is carried out at 70ºC for 72 hours. After the reaction is completed, the reaction liquid is placed in a dialysis bag for dialysis purification for three to five days, and finally vacuum freeze-dried to obtain PVA-EPL powder for further use; the structure of PVA-EPL is as follows: ; wherein n1 is 100, n2 is 500, and n3 is 400.

[0061] S4, the obtained OEDX is dissolved in ultrapure water to prepare a solution with a mass fraction of 10%, PVA-EPL is dissolved in ultrapure water to prepare a solution with a mass fraction of 30%, boric acid is dissolved in ultrapure water to prepare a solution with a mass fraction of 2%, and MWCNTs are ultrasonically dispersed in ultrapure water at a concentration of 1.5 mg / mL. The PVA-EPL, OEDX, MWCNTs and boric acid solutions are quickly mixed in a volume ratio of 5:2:3:2 to obtain a super-strong tensile and fast-crosslinked antibacterial conductive skeletal muscle repair hydrogel scaffold.

[0062] Example 5 A method for preparing an antibacterial conductive skeletal muscle repair hydrogel scaffold, comprising the following steps: S1, first, dextran is added to ultrapure water, and the dextran is dissolved by stirring at room temperature. Then, sodium periodate is added, and the molar ratio of dextran to sodium periodate is 1:2. The reaction temperature is then increased to 50°C and stirred for 24 hours. After the reaction is completed, ethylene glycol is added and stirred for 2 hours to terminate the oxidation reaction. Then, the reaction solution is placed in a dialysis bag for dialysis purification for three to five days, and finally, ODEX powder is obtained by vacuum freeze-drying for further use; the structure of ODEX is as follows:

[0063] wherein x is 10 and y is 100.

[0064] S2, polyvinyl alcohol is added to ultrapure water, and the polyvinyl alcohol is dissolved by stirring at 70°C. Then, methacrylic anhydride is added, and the molar ratio of polyvinyl alcohol to methacrylic anhydride is 1:2. Then, the reaction is carried out in the dark for 48 hours. After the reaction is completed, the reaction solution is placed in a dialysis bag for dialysis purification for three to five days, and finally, a PVAMA solution is obtained by rotary evaporation for further use; PVAMA: ; wherein n is 550.

[0065] S3, the pH value of the PVAMA solution is adjusted to 8.0. Then, 2.04 g of polypeptide ε-polylysine and 0.096 g of potassium carbonate are added to the PVAMA solution, and the reaction is carried out at 70°C for 72 hours. After the reaction is completed, the reaction solution is placed in a dialysis bag for dialysis purification for three to five days, and finally, PVA-EPL powder is obtained by vacuum freeze-drying for further use; the structure of PVA-EPL is as follows: ; wherein n1 is 50, n2 is 550, and n3 is 500.

[0066] S4, the obtained OEDX is dissolved in ultrapure water to prepare a solution with a mass fraction of 10%, PVA-EPL is dissolved in ultrapure water to prepare a solution with a mass fraction of 30%, boric acid is dissolved in ultrapure water to prepare a solution with a mass fraction of 2%, and MWCNTs are ultrasonically dispersed in ultrapure water at a concentration of 2mg / mL, and the PVA-EPL, OEDX, MWCNTs and boric acid solutions are quickly mixed in a volume ratio of 5:2:3:2 to obtain an antibacterial and conductive skeletal muscle repair hydrogel scaffold with super tensile strength and rapid crosslinking.

[0067] The performance of the antibacterial and conductive skeletal muscle repair hydrogel scaffold of embodiments 1-4 was determined, and the results are shown in Table 1.

[0068] The shape recovery degree is determined by using a rotational rheometer to test the shape adaptability of the hydrogel, and the diameter of the parallel plate of the rheometer is 20mm. The storage modulus (G') and loss modulus (G'') of the hydrogel are determined at an environmental temperature of 25℃ within a strain range of 1%, so as to indicate the strength of the gel. Subsequently, the environmental temperature is selected as 25℃, the strain is selected as 1% and 1000%, the hydrogel is set to cycle between the two strains for 5 times, and the modulus change obtained by the oscillation scan can directly reflect the shape adaptability of the hydrogel.

[0069] Table 1: Performance determination results of the antibacterial and conductive skeletal muscle repair hydrogel scaffold The ε-polylysine used in the application is an additive widely used in food, industry and medical treatment, which has good biocompatibility, high antibacterial efficiency, environmental friendliness and low cost. After grafting with polyvinyl alcohol, the antibacterial property of polyvinyl alcohol can be effectively improved. The multi-walled carbon nanotubes can effectively ensure the photothermal antibacterial property and conductivity of the hydrogel scaffold. The solvent used is ultrapure water, and the skeletal muscle repair material prepared by the hydrogel scaffold does not contain any organic solvent. Moreover, the preparation method is fast and simple, the raw materials are green and environmentally friendly, and the cost is low. The prepared hydrogel scaffold can effectively resist pathogenic bacteria and has good biocompatibility in vivo and in vitro. Under the actions of excellent tensile property, self-healing property and shape adaptability, the hydrogel scaffold can well adapt to the dynamic microenvironment of skeletal muscle tissue, and therefore has a good application prospect in skeletal muscle tissue engineering.

[0070] The above is only a preferred embodiment of the application, and is not intended to limit the application. Any modification, equivalent replacement and improvement made within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. An antibacterial conductive skeletal muscle repair hydrogel scaffold, characterized in that: It is prepared by the following method: Polylysine-modified polyvinyl alcohol, aldehyde-modified dextran, and carbon nanotubes are dispersed in a boric acid solution. The aldehyde groups in the aldehyde-modified dextran undergo a nucleophilic addition reaction with the amino groups of the polylysine-modified polyvinyl alcohol to form imine bonds, resulting in a dynamic Schiff base structure. The carbon nanotubes react with the hydroxyl groups of the polylysine-modified polyvinyl alcohol and the aldehyde-modified dextran to form hydrogen bonds. The hydroxyl groups in the polylysine-modified polyvinyl alcohol react with boric acid to form borate ester bonds to cross-link into a gel, resulting in an antibacterial and conductive skeletal muscle repair hydrogel scaffold. The cross-linking time is 5s to 30s.

2. The antibacterial conductive skeletal muscle repair hydrogel scaffold according to claim 1, characterized in that: The aldehyde-dextran is obtained by oxidation of dextran under the action of periodic acid.

3. The antibacterial conductive skeletal muscle repair hydrogel scaffold according to claim 1, characterized in that: The polylysine-modified polyethylene is prepared by esterifying polyvinyl alcohol with methacrylic anhydride to obtain methacrylated polyvinyl alcohol, and then grafting polylysine onto the methacrylated polyvinyl alcohol through Michael addition reaction under the action of a catalyst to obtain polylysine-modified polyvinyl alcohol.

4. A method for preparing the antibacterial conductive skeletal muscle repair hydrogel scaffold according to any one of claims 1 to 3, characterized in that: The following steps are involved: Polyvinyl alcohol and methacrylic anhydride are subjected to an esterification reaction in an aqueous environment to obtain methacrylated polyvinyl alcohol; polylysine is grafted onto the methacrylated polyvinyl alcohol through a Michael addition reaction under the action of a catalyst to obtain polylysine-modified polyvinyl alcohol; Dextran is treated with sodium periodate in a water environment and protected from light, and the hydroxyl groups of the dextran are oxidized into aldehyde groups through an oxidation reaction to obtain aldehyde-modified dextran; Dispersing poly(vinyl alcohol) modified with polylysine, aldehyde-modified dextran and carbon nanotubes in a boric acid solution to obtain the antibacterial conductive skeletal muscle repair hydrogel scaffold; The mass percentage of the boric acid solution is 2% to 2.5%; The mass ratio of polylysine-modified polyvinyl alcohol, oxidized dextran, carbon nanotubes, and boric acid solution is 5-4: 1-2:1-3:

2.

5. The preparation method according to claim 4, characterized in that The molar ratio of the methacrylic anhydride to the polyvinyl alcohol is 0.5 to 2:1; The esterification reaction temperature is 60° C. to 70° C., and the reaction time is 24 h to 48 h.

6. The preparation method according to claim 4, characterized in that The molar ratio of the polylysine to the methacrylated polyvinyl alcohol is 0.5 to 2:1; The temperature of the Michael addition reaction is 60° C. to 70° C., and the reaction time is 48 h to 72 h.

7. The preparation method according to claim 4, characterized in that The catalyst is potassium carbonate or cesium carbonate, and the molar ratio of the catalyst to polylysine is 0.5-3:

1.

8. The preparation method according to claim 4, characterized in that The molar ratio of the sodium periodate to the dextran is 0.5-3:1; The oxidation reaction temperature is 30° C. to 50° C., and the stirring reaction is carried out for 24 h to 48 h.

9. Use of the antibacterial conductive skeletal muscle repair hydrogel scaffold according to any one of claims 1 to 3 in the preparation of a product that promotes myogenic differentiation and healing of infected skeletal muscle defects.

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