Injectable piezoelectric hydrogel and preparation method thereof

Abstract

The invention relates to the technical field of biomedical materials and application thereof in tissue engineering, in particular to injectable piezoelectric hydrogel and a preparation method thereof.The hydrogel comprises polyvinyl alcohol, polyacrylic acid, polydopamine and I-type collagen and further comprises sodium hydroxide, a cross-linking agent, a catalyst and an initiator, finally, the injectable polyvinyl alcohol / polyacrylic acid / polydopamine hydrogel is obtained, and the postoperative rehabilitation effect of anterior cruciate ligament reconstruction can be remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of biomedical materials and their application in tissue engineering, in particular to an injectable piezoelectric hydrogel and a preparation method thereof. Background Art

[0002] The anterior cruciate ligament is an important structure of the knee joint, responsible for maintaining the stability of the joint and preventing anterior displacement and excessive rotation of the tibia. Anterior cruciate ligament injuries are particularly common in adolescents and usually require repair through anterior cruciate ligament reconstruction. The operation involves fixing the transplanted tendon in the bone tunnel to replace the damaged anterior cruciate ligament. The existing fixation methods mainly include direct fixation with interference screws and indirect fixation with cortical suspension. Interference screw fixation achieves fixation through the friction between the screw and the tendon, but there is a risk of unstable fixation and tendon rupture. The indirect fixation method causes the "wiper effect" and "bungee effect" due to the gap between the graft and the bone tunnel, which affects the biological healing process. At present, the fixation method of anterior cruciate ligament reconstruction mainly relies on mechanical fixation. Although the use of interface screws improves the stability after reconstruction, it also brings about the problem of reduced graft strength. Smaller screws cannot provide sufficient mechanical force, while larger screws may cut sutures and grafts, resulting in unstable fixation. Although the indirect fixation method avoids direct mechanical damage, due to the presence of gaps, the graft will experience unstable swinging and expansion during movement, further affecting the biological healing of the tendon and bone. In addition, hydrogel, as a biocompatible material, has been widely used in tissue engineering, but its adhesion and strength will be reduced in a humid environment, limiting its application in anterior cruciate ligament reconstruction.

[0003] In the prior art, the deficiencies of fixation materials in anterior cruciate ligament (ACL) reconstruction surgery include the following aspects: first, the existing interface screw fixation method easily leads to a decrease in graft strength, increases the risk of tendon rupture, and affects the surgical effect; second, the indirect fixation method has gaps, resulting in a "wiper effect" and a "bungee effect", which affects the biological healing process of tendon-bone and may cause the expansion of bone tunnels, further affecting the patient's recovery; finally, the existing hydrogel has insufficient adhesion in a humid environment and cannot effectively support cell growth and tissue regeneration. Therefore, there is an urgent need for a new type of fixation material that can maintain good adhesion in a humid environment and promote biological healing of the tendon-bone interface. Summary of the invention

[0004] The present invention mainly solves the deficiencies of existing fixation materials in anterior cruciate ligament reconstruction surgery and provides a new type of fixation material that can maintain good adhesion properties in a moist environment and promote biological healing of the tendon-bone interface.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] An injectable piezoelectric hydrogel, the hydrogel comprising polyvinyl alcohol, polyacrylic acid, polydopamine and type I collagen;

[0007] The hydrogel also includes sodium hydroxide, a cross-linking agent, a catalyst and an initiator;

[0008] The cross-linking agent is N,N'-methylenebisacrylamide, the catalyst is tetramethylethylenediamine, and the initiator is potassium persulfate.

[0009] Preferably, the sodium hydroxide is 10 grams, the sodium hydroxide solution contains 10 mol / L sodium hydroxide, and the sodium hydroxide solution is 50 milliliters.

[0010] Preferably, the formula ratio of polyvinyl alcohol, polyacrylic acid, polydopamine, N,N'-methylenebisacrylamide, type I collagen, sodium hydroxide, tetramethylethylenediamine and potassium persulfate is 5:1:1:0.01:0.5:0.5:100:0.1.

[0011] Preferably, the weight of the polyvinyl alcohol is 2 grams, the polyacrylic acid is 1 gram, the polydopamine is 1 gram, the N,N'-methylenebisacrylamide is 0.01 gram, the type I collagen is 0.5 gram, the sodium hydroxide is 0.5 gram, the tetramethylethylenediamine is 0.0001 gram, and the weight of the potassium persulfate is 0.1 gram.

[0012] Preferably, the polyvinyl alcohol is a linear high molecular polymer, which is polymerized from vinyl acetate and contains side groups - hydroxyl groups on the molecular chain; the polyacrylic acid is a negatively charged water-soluble polyelectrolyte; the polyacrylic acid polymer contains carboxyl groups on the main chain; the polydopamine includes a variety of functional groups that can serve as starting points for covalent modification of the molecule, including any one of catechol, amine and imine; the type I collagen includes an active protein with a triple helical structure.

[0013] A method for preparing an injectable piezoelectric hydrogel, the method comprising the following steps:

[0014] Step S1: completely dissolving polyvinyl alcohol in deionized water in a water bath to form a polyvinyl alcohol solution;

[0015] Step S2: uniformly mixing polyacrylic acid in a polyvinyl alcohol solution to prepare a polyvinyl alcohol / polyacrylic acid mixed solution;

[0016] Step S3: completely dissolving sodium hydroxide in a deionized solution to obtain a sodium hydroxide solution; then adding dopamine hydrochloride into deionized water to obtain a polydopamine solution;

[0017] Step S4: adding the polyvinyl alcohol / polyacrylic acid mixed solution and the polydopamine solution into a beaker and fully blending them to obtain a polyvinyl alcohol / polyacrylic acid and polydopamine mixed solution;

[0018] Step S5: adding N,N'-methylenebisacrylamide to the mixed solution of polyvinyl alcohol / polyacrylic acid and polydopamine, stirring and fusing to form a dispersion, adding type I collagen and 10 mol / L sodium hydroxide solution to the dispersion after ultrasonic oscillation for 30 minutes to obtain a dispersion / type I collagen / sodium hydroxide mixed solution;

[0019] Step S6: adding tetramethylethylenediamine to the dispersion / type I collagen / sodium hydroxide mixed solution, and finally adding potassium persulfate, reacting in a water bath, and finally obtaining an injectable polyvinyl alcohol / polyacrylic acid / polydopamine hydrogel.

[0020] Preferably, the deionized water in step S1 is 100 ml, the polyvinyl alcohol is 2 g, the water bath temperature is 90° C., the polyvinyl alcohol solution formed after the polyvinyl alcohol is melted is 2 wt %, and the polyacrylic acid in step S2 is 1 ml.

[0021] Preferably, the sodium hydroxide in step S3 is 10 grams, the sodium hydroxide solution formed after the sodium hydroxide is melted contains 10 mol / L sodium hydroxide, the sodium hydroxide solution is 50 milliliters, the dopamine hydrochloride is 0.01 grams, the deionized water is 100 milliliters, the polyvinyl alcohol / polyacrylic acid mixed solution in S4 is 5 milliliters, and the polydopamine solution is 1 milliliter.

[0022] Preferably, in step S5, the amount of N,N'-methylenebisacrylamide is 0.01 g, the amount of type I collagen is 0.5 ml, and the amount of 10 mol / L sodium hydroxide solution is 0.5 ml.

[0023] Preferably, in step S6, the amount of tetramethylethylenediamine is 100 μg, the amount of potassium persulfate is 0.1 g, and the temperature of the water bath is 50°C.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The injectable polyvinyl alcohol / polyacrylic acid / polydopamine hydrogel of the present invention exhibits excellent adhesion and mechanical properties in a moist environment, can effectively fix the graft, reduce the risk of tendon rupture, and promote the biological healing of the tendon-bone interface. By introducing polydopamine and collagen, the biocompatibility of the hydrogel is significantly improved, which can support cell growth and tissue regeneration, and improve the rehabilitation effect after anterior cruciate ligament reconstruction.

[0026] 2. Inject the polyvinyl alcohol / polyacrylic acid / polydopamine injectable hydrogel into the tendon-bone interface so that it can firmly adhere to the tendon in the bone tunnel in a moist environment, thereby achieving the purpose of fixing the transplanted tendon. The hydrogel has the advantages of strong viscosity in a moist environment, long-term stability, and the ability to resist shear stress.

[0027] 3. Polyvinyl alcohol / polyacrylic acid / polydopamine injectable hydrogel is used to fix transplanted tendons. It can prevent the cutting of sutures and transplants during fixation with interface screws, avoid tendon rupture and failure due to decreased strength of the transplanted tendon, and can also be used to shield the pressure of the interface screw in the bone tunnel. Polyvinyl alcohol / polyacrylic acid / polydopamine injectable hydrogel can fix transplanted tendons and fully fill the gap between tendon and bone. While firmly fixing the graft, it prevents the "wiper effect" and "bungee effect", avoids the expansion of the bone tunnel, and affects tendon-bone healing. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a flow chart of the preparation method of the present invention;

[0029] Figure 2 A coronal view of the present invention using a high-viscosity hydrogel to fix a transplanted tendon in anterior cruciate ligament reconstruction;

[0030] Figure 3 A cross-sectional view of the present invention using a high-viscosity hydrogel to fix a transplanted tendon in anterior cruciate ligament reconstruction;

[0031] Figure 4 The flowchart of the construction of the polyvinyl alcohol / polyacrylic acid / polydopamine injectable hydrogel of the present invention;

[0032] Figure 5 This is a diagram demonstrating the injectability of the polyvinyl alcohol / polyacrylic acid / polydopamine hydrogel of the present invention;

[0033] Figure 6 This is a demonstration diagram of the adhesion (glass) of the polyvinyl alcohol / polyacrylic acid / polydopamine injectable hydrogel of the present invention to dry tissue;

[0034] Figure 7 This is a demonstration diagram of the adhesion of the polyvinyl alcohol / polyacrylic acid / polydopamine injectable hydrogel of the present invention to wet tissue (tendon). DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present invention will be described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] See also Figures 1 to 7 The present invention provides an injectable piezoelectric hydrogel, and the technical solution is as follows:

[0037] An injectable piezoelectric hydrogel, the hydrogel comprising polyvinyl alcohol, polyacrylic acid, polydopamine and type I collagen;

[0038] The hydrogel also includes sodium hydroxide, a cross-linking agent, a catalyst and an initiator;

[0039] The cross-linking agent is N,N'-methylenebisacrylamide, the catalyst is tetramethylethylenediamine, and the initiator is potassium persulfate.

[0040] The polyvinyl alcohol is a linear high molecular polymer, which is polymerized from vinyl acetate under certain conditions. It contains a large number of side groups - hydroxyl groups on the molecular chain, can be dissolved in water in various proportions, and is a hard glassy solid at room temperature. It has good thermal stability. It can be dissolved in water in any proportion, and the aqueous solution is a uniform and transparent liquid. Since the widely distributed hydroxyl side chains on the polyvinyl alcohol molecules can be branched with various functional groups, the polyvinyl alcohol-based hydrogel has excellent cell compatibility, viscoelasticity and antibacterial properties, and has been widely used in tissue repair and regeneration.

[0041] The polyacrylic acid is a negatively charged water-soluble polyelectrolyte, and its polymer main chain contains carboxyl groups, which can interact with a variety of other polymers or molecules intermolecularly (e.g., hydrogen bonds, ionic bonds, complexation reactions, etc.), and is an excellent hydrogel matrix. Polyacrylic acid hydrogel has the advantages of high mechanical strength and ionic conductivity, and is an ideal candidate material for flexible electronic devices, sensors, and mobile energy. Cross-linking is achieved through the high hydrogen bond density between polyvinyl alcohol and polyacrylic acid and the physical entanglement of polymer chains, which enhances the cohesion of the hydrogel.

[0042] The polydopamine is a typical melanin analog, containing a variety of functional groups that can be used as starting points for molecular covalent modification, such as catechol, amine and imine, and is formed by polymerization of dopamine. During the polymerization process, the catechol group of dopamine loses an electron and becomes a dopamine-semiquinone structure. The dopamine-semiquinone free radical induces dimerization between molecules to form catechol-catechol dimers. Polydopamine is a multifunctional new bionic material that has non-selective strong adhesion properties to the surfaces of various solid materials, can simulate the function of adhesion proteins secreted by mollusks, and is durable and stable. The polydopamine undergoes a nucleophilic addition reaction with the hydroxyl group of polyvinyl alcohol through its aldehyde group to form a covalent bond, and at the same time undergoes an esterification reaction with the carboxyl group in polyacrylic acid, further enhancing the three-dimensional network structure of the hydrogel.

[0043] The type I collagen is an active protein with a triple helix structure. It has good low immunogenicity and biocompatibility, commonly known as "physiological glue", and has strong adhesion and contractility. The type I collagen promotes cell adhesion and proliferation by binding to cell surface receptors, while enhancing the mechanical properties of the hydrogel to form a stable three-dimensional network structure.

[0044] The N,N'-methylenebisacrylamide can form covalent bonds between polymer chains through polymerization reaction, thereby achieving cross-linking. Therefore, N,N'-methylenebisacrylamide can form cross-links in polyacrylamide gel to create a network structure, which can significantly improve the strength and stability of the material.

[0045] The type I collagens are further connected by covalent cross-linking, and these cross-linking bonds can enhance the stability and strength of the collagen network.

[0046] The tetramethylethylenediamine can reduce the activation energy of the chemical reaction, so that the reactants can more easily reach the energy state required for the reaction, thereby accelerating the formation of the gel.

[0047] The potassium persulfate generates free radicals by decomposition and initiates chain growth and cross-linking reactions, thereby significantly improving the performance of the polymer and making the polymerization reaction more rapid and efficient.

[0048] The sodium hydroxide is 10 grams, the sodium hydroxide solution contains 10 mol / L sodium hydroxide, the sodium hydroxide solution is 50 milliliters, and the sodium hydroxide can adjust the pH value, promote the dissolution and catalysis of collagen, and accelerate the reaction process.

[0049] The formula ratio of the polyvinyl alcohol, polyacrylic acid, polydopamine, N,N'-methylenebisacrylamide, type I collagen, sodium hydroxide, tetramethylethylenediamine and potassium persulfate is 5:1:1:0.01:0.5:0.5:100:0.1.

[0050] The formula ratio precisely controls the proportion of each component through the synergistic effect between the components, realizes the integration and optimization of multiple functions, and has broad application prospects.

[0051] The weight of the polyvinyl alcohol is 2 grams, the weight of the polyacrylic acid is 1 gram, the weight of the polydopamine is 1 gram, the weight of the N,N'-methylenebisacrylamide is 0.01 gram, the weight of the type I collagen is 0.5 gram, the weight of the sodium hydroxide is 0.5 gram, the weight of the tetramethylethylenediamine is 0.0001 gram, and the weight of the potassium persulfate is 0.1 gram. By using these ingredients in specific gram weights for formulation, the strength and stability of the hydrogel can be improved, and the graft can be effectively fixed.

[0052] The polyvinyl alcohol is a linear high molecular polymer, which is polymerized from vinyl acetate and contains a side group - hydroxyl group on the molecular chain. The polyacrylic acid is a water-soluble polyelectrolyte with a negative charge, and the main chain of the polyacrylic acid polymer contains a carboxyl group. The polydopamine includes a variety of functional groups that can be used as starting points for molecular covalent modification, including any one of catechol, amine and imine, etc. The type I collagen includes an active protein with a triple helical structure.

[0053] A cross-linked structure is formed through the interaction of hydrogen bonds, ionic bonds, etc. in polyvinyl alcohol and polyacrylic acid, thereby improving the stability and strength of the hydrogel. The adhesion and functional groups of polydopamine can react with the functional groups of polyvinyl alcohol and polyacrylic acid to further promote cross-linking and stabilization of type I collagen to promote the dissolution and dispersion of collagen.

[0054] A method for preparing an injectable piezoelectric hydrogel, the method comprising:

[0055] Step S1: dissolving polyvinyl alcohol in deionized water to form a polyvinyl alcohol solution.

[0056] Step S2: uniformly mixing polyacrylic acid in a polyvinyl alcohol solution to prepare a polyvinyl alcohol / polyacrylic acid mixed solution;

[0057] Step S3: completely dissolving sodium hydroxide in a deionized solution to obtain a sodium hydroxide solution; then adding dopamine hydrochloride into deionized water to obtain a polydopamine solution;

[0058] Step S4: adding the polyvinyl alcohol / polyacrylic acid mixed solution and the polydopamine solution into a beaker and fully blending them to obtain a polyvinyl alcohol / polyacrylic acid and polydopamine mixed solution;

[0059] Step S5: Add N,N'-methylenebisacrylamide to the mixed solution of polyvinyl alcohol / polyacrylic acid and polydopamine, stir and blend thoroughly to form a dispersion, add type I collagen and 10 mol / L sodium hydroxide solution to the dispersion after ultrasonic oscillation for 30 minutes to obtain a dispersion / type I collagen / sodium hydroxide mixed solution.

[0060] Step S6: adding tetramethylethylenediamine to the dispersion / type I collagen / sodium hydroxide mixed solution, and finally adding potassium persulfate, reacting in a water bath, and finally obtaining an injectable polyvinyl alcohol / polyacrylic acid / polydopamine hydrogel.

[0061] The deionized water in step S1 is 100 ml, the polyvinyl alcohol is 2 g, the water bath temperature is 90° C., the polyvinyl alcohol solution formed after the polyvinyl alcohol is melted is 2 wt%, and the polyacrylic acid in step S2 is 1 ml. The mixture of polyvinyl alcohol and deionized water is placed in a 90° C. water bath and stirred for 30 minutes until the polyvinyl alcohol is completely dissolved to form a 2 wt% polyvinyl alcohol solution. The polyacrylic acid is added to the polyvinyl alcohol solution and stirred for 15 minutes to ensure that the polyacrylic acid is evenly dispersed in the polyvinyl alcohol solution.

[0062] In the step S3, the sodium hydroxide is 10 grams, the sodium hydroxide solution formed after the sodium hydroxide is melted contains 10 mol / L sodium hydroxide, the sodium hydroxide solution is 50 milliliters, the dopamine hydrochloride is 0.01 grams, the deionized water is 100 milliliters, the polyvinyl alcohol / polyacrylic acid mixed solution in S4 is 5 milliliters, and the polydopamine solution is 1 milliliter. When the polyvinyl alcohol / polyacrylic acid mixed solution and the polydopamine solution are added to the beaker, stir for 15 minutes to ensure that the two are fully mixed.

[0063] In the step S5, the amount of N,N'-methylenebisacrylamide is 0.01 g, the amount of type I collagen is 0.5 ml, and the amount of 10 mol / L sodium hydroxide solution is 0.5 ml. N,N'-methylenebisacrylamide is added to the polyvinyl alcohol / polyacrylic acid / polydopamine mixture, and stirring is continued for 15 minutes to form a dispersion having a cross-linked structure, good dispersion stability and improved performance.

[0064] In step S6, the amount of tetramethylethylenediamine is 100 μg, the amount of potassium persulfate is 0.1 g, and the temperature of the water bath is 50°C. When potassium persulfate and tetramethylethylenediamine act together, the cross-linking reaction between type I collagen and polyvinyl alcohol / polyacrylic acid / polydopamine can be promoted. The water bath temperature of 50°C can further accelerate the cross-linking reaction between type I collagen and polyvinyl alcohol / polyacrylic acid / polydopamine.

[0065] Through the above implementation scheme, the present invention successfully constructed an injectable vinyl alcohol / polyacrylic acid / polydopamine hydrogel with excellent adhesion and mechanical properties, which can effectively fix the graft in anterior cruciate ligament reconstruction, reduce the risk of tendon rupture, and promote the biological healing of the tendon-bone interface. The experimental results show that the hydrogel has good prospects in biomedical applications, can effectively solve many problems in the existing technology, and significantly improve the rehabilitation effect after anterior cruciate ligament reconstruction.

Claims

1. An injectable piezoelectric hydrogel, characterized in that: The hydrogel comprises polyvinyl alcohol, polyacrylic acid, polydopamine and type I collagen; The hydrogel also includes sodium hydroxide, a cross-linking agent, a catalyst and an initiator; The cross-linking agent is N,N'-methylenebisacrylamide, the catalyst is tetramethylethylenediamine, and the initiator is potassium persulfate.

2. The injectable piezoelectric hydrogel according to claim 1, characterized in that: The sodium hydroxide is 10 grams, the sodium hydroxide solution contains 10 mol / L sodium hydroxide, and the sodium hydroxide solution is 50 milliliters.

3. The injectable piezoelectric hydrogel according to claim 1, characterized in that: The formula ratio of the polyvinyl alcohol, polyacrylic acid, polydopamine, N,N'-methylenebisacrylamide, type I collagen, sodium hydroxide, tetramethylethylenediamine and potassium persulfate is 5:1:1:0.01:0.5:0.5:100:0.

1.

4. The injectable piezoelectric hydrogel according to claim 1, characterized in that: The weight of the polyvinyl alcohol is 2 grams, the polyacrylic acid is 1 gram, the polydopamine is 1 gram, the N,N'-methylenebisacrylamide is 0.01 gram, the type I collagen is 0.5 gram, the sodium hydroxide is 0.5 gram, the tetramethylethylenediamine is 0.0001 gram, and the weight of the potassium persulfate is 0.1 gram.

5. The injectable piezoelectric hydrogel according to claim 1, characterized in that: The polyvinyl alcohol is a linear high molecular polymer, which is polymerized from vinyl acetate and contains side groups - hydroxyl groups on the molecular chain; The polyacrylic acid is a water-soluble polyelectrolyte with a negative charge; The polyacrylic acid polymer main chain contains carboxyl groups; The polydopamine includes a variety of functional groups that can be used as starting points for covalent modification of molecules, including any one of catechol, amine and imine; The type I collagen includes active proteins having a triple helical structure.

6. A method for preparing an injectable piezoelectric hydrogel according to any one of claims 1 to 5, characterized in that: The preparation method comprises the following steps: Step S1: completely dissolving polyvinyl alcohol in deionized water in a water bath to form a polyvinyl alcohol solution; Step S2: uniformly mixing polyacrylic acid in a polyvinyl alcohol solution to prepare a polyvinyl alcohol / polyacrylic acid mixed solution; Step S3: completely dissolving sodium hydroxide in a deionized solution to obtain a sodium hydroxide solution; then adding dopamine hydrochloride into deionized water to obtain a polydopamine solution; Step S4: adding the polyvinyl alcohol / polyacrylic acid mixed solution and the polydopamine solution into a beaker and fully blending them to obtain a polyvinyl alcohol / polyacrylic acid and polydopamine mixed solution; Step S5: adding N,N'-methylenebisacrylamide to the mixed solution of polyvinyl alcohol / polyacrylic acid and polydopamine, stirring and fusing to form a dispersion, adding type I collagen and 10 mol / L sodium hydroxide solution to the dispersion after ultrasonic oscillation for 30 minutes to obtain a dispersion / type I collagen / sodium hydroxide mixed solution; Step S6: adding tetramethylethylenediamine to the dispersion / type I collagen / sodium hydroxide mixed solution, and finally adding potassium persulfate, reacting in a water bath, and finally obtaining an injectable polyvinyl alcohol / polyacrylic acid / polydopamine hydrogel.

7. The method for preparing the injectable piezoelectric hydrogel according to claim 6, characterized in that: The deionized water in step S1 is 100 ml, the polyvinyl alcohol is 2 g, the water bath temperature is 90° C., the polyvinyl alcohol solution formed after the polyvinyl alcohol is melted is 2 wt %, and the polyacrylic acid in step S2 is 1 ml.

8. The method for preparing the injectable piezoelectric hydrogel according to claim 6, characterized in that: In the step S3, the sodium hydroxide is 10 g, the sodium hydroxide solution formed after the sodium hydroxide is melted contains 10 mol / L sodium hydroxide, the sodium hydroxide solution is 50 ml, the dopamine hydrochloride is 0.01 g, the deionized water is 100 ml, the polyvinyl alcohol / polyacrylic acid mixed solution in S4 is 5 ml, and the polydopamine solution is 1 ml.

9. The method for preparing the injectable piezoelectric hydrogel according to claim 6, characterized in that: In the step S5, the amount of N,N'-methylenebisacrylamide is 0.01 g, the amount of type I collagen is 0.5 ml, and the amount of 10 mol / L sodium hydroxide solution is 0.5 ml.

10. The method for preparing the injectable piezoelectric hydrogel according to claim 6, characterized in that: In step S6, the amount of tetramethylethylenediamine is 100 μg, the amount of potassium persulfate is 0.1 g, and the temperature of the water bath is 50° C.

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