Preparation method and application of silk fibroin-gelma composite conductive hydrogel

Abstract

The embodiment of the application provides a preparation method of a silk-GelMA composite conductive hydrogel, which comprises the following steps: dissolving GelMA in a PBS solution, adding a photoinitiator, mixing with a silk fibroin solution, adding glutaraldehyde, uniformly mixing, performing light irradiation under ultraviolet light, constant-temperature drying, and obtaining a double-network hydrogel; first immersing the double-network hydrogel in an ammonium persulfate aqueous solution, standing, transferring to a pyrrole aqueous solution for immersion, stopping the reaction, and drying to obtain the silk-GelMA composite conductive hydrogel; the silk-GelMA composite conductive hydrogel obtained in this way is matched with the mechanical properties of nerve tissue, is suitable for the construction of a nerve tissue engineering scaffold, has appropriate electrical conductivity, reaches the ideal nerve tissue electrical conductivity range, promotes nerve regeneration, and at the same time, the swelling rate meets the requirements of nerve tissue, so that the use of the hydrogel in an in-vivo tissue can avoid damage and destruction to other surrounding tissues; and the application also provides the silk-GelMA composite conductive hydrogel obtained by using the preparation method.

Description

Technical Field

[0001] This invention relates to a method for preparing and applying a silk fibroin-GelMA composite conductive hydrogel. Background Technology

[0002] Damage to the nervous system causes immense physical and psychological suffering for patients. With advancements in technology, research on the repair of nervous system injuries is increasingly prevalent. Studies have found that silk fibroin, containing various amino acids, possesses excellent biocompatibility, mechanical properties, and physicochemical properties. When prepared into a gel, it can promote tissue repair. Therefore, in the field of nervous system injury, further research is being conducted focusing on silk fibroin gels. For example, document CN116370403 A, entitled "An Injectable Hydrogel for Spinal Cord Injury Repair and Its Preparation Method and Application," presents an injectable hydrogel for spinal cord injury repair. This hydrogel, obtained by mixing an aqueous solution of silk fibroin with an aqueous solution of hydrotalcite and allowing it to stand, exhibits good structural stability, excellent shear thinning and self-repairing properties. It can effectively remove excessive reactive oxygen species (ROS) generated at the injury site, alleviate inflammatory responses, and simultaneously generate oxygen in the microenvironment, effectively improving the hypoxic conditions at the injury site, promoting nerve cell growth and differentiation, and facilitating rapid repair of spinal cord injuries.

[0003] Further in-depth research revealed that, in the field of nerve repair, existing repair materials have poor conductivity during the repair process, affecting the exchange of substances between nerves and surrounding tissues and the conduction of cellular electrical signals. Summary of the Invention

[0004] Therefore, the present invention provides a method for preparing a silk fibroin-GelMA composite conductive hydrogel to meet the above requirements.

[0005] A method for preparing a silk fibroin-GelMA composite conductive hydrogel includes the following steps: S1: Preparation of dual-network hydrogel: GelMA was dissolved in PBS solution to prepare a solution with a mass-volume concentration of 10±1%. A photoinitiator was added, with the mass-volume ratio of the photoinitiator to the system volume being 1.5±0.1%, to obtain a GelMA solution. Then, it was mixed with a silk fibroin solution with a concentration of 10±1% at a volume ratio of 5:(5±1). Glutaraldehyde was added, with the mass ratio of silk fibroin to glutaraldehyde being 1:(0.1±0.01). The mixture was mixed evenly to obtain a prepolymer mixture. The prepolymer mixture was irradiated under ultraviolet light and dried at a constant temperature to obtain a dual-network hydrogel. S2: Preparation of silk fibroin-GelMA composite conductive hydrogel: Prepare a pyrrole aqueous solution with a concentration of 0.8%-1.2% and a 1±0.1 M ammonium persulfate aqueous solution. Immerse the double network hydrogel in the ammonium persulfate aqueous solution for 30-90 min, let it stand, transfer it to the pyrrole aqueous solution for 30-60 min, then transfer it to deionized water to stop the reaction, and dry it to obtain the silk fibroin-GelMA composite conductive hydrogel.

[0006] GelMA is obtained by dissolving gelatin powder in PBS and stirring in a water bath until completely dissolved to obtain a gelatin solution. Methacrylic anhydride is added dropwise to the gelatin solution, stirred, and then PBS is added. The mixture is dialyzed, centrifuged, and the supernatant is collected and stored at low temperature or freeze-dried to obtain GelMA.

[0007] The silk fibroin solution is obtained through the following method: Silk degumming: Heat deionized water to boiling, add Na2CO3, and after it is completely dissolved, put raw silk into it and degumming is carried out under boiling conditions. Then wash and dry to obtain silk fibroin fiber. Dissolution and dialysis of silk fibroin: The silk fibroin fibers were dissolved in 9.3±0.2 M lithium bromide solution at a bath ratio of (2.7±0.2):10. After complete dissolution, the solution was cooled to room temperature, then placed in a dialysis bag and sealed. The lithium bromide was removed by dialysis, and the solution was centrifuged to obtain the silk fibroin solution.

[0008] In step S1, the mass ratio of silk fibroin to glutaraldehyde is 1:0.1, the volume ratio of silk fibroin solution to GelMA solution is 5:5, and the mass ratio of photoinitiator to system volume is 1.5%.

[0009] In step S2, the concentration of the pyrrole aqueous solution is 0.8-1.0%, the immersion time in the ammonium persulfate solution is 60-90 min, and the immersion time in the pyrrole solution is 30-45 min.

[0010] In step S2, the concentration of the pyrrole aqueous solution is 0.8%, the immersion time in the ammonium persulfate solution is 90 min, and the immersion time in the pyrrole solution is 30 min.

[0011] In step S2, the standing time specifically refers to standing in a glass dish for 30 minutes, the transfer to deionized water to stop the reaction specifically refers to transferring to deionized water for 30 minutes to stop the reaction and cleaning off any excess aggregates on the surface, and the drying time refers to drying in a 60°C oven for 10 minutes.

[0012] The photoinitiator is Irgacure 2959, the ultraviolet light is 365 nm ultraviolet light, and the irradiation time is 15-30 min.

[0013] The present invention also provides a silk fibroin-GelMA composite conductive hydrogel, which is prepared by the above-described preparation method.

[0014] The conductivity of the silk fibroin-GelMA composite conductive hydrogel is greater than or equal to 0.49 × 10⁻⁶. -2 S / cm.

[0015] Beneficial Effects: This invention provides a method for preparing a silk fibroin-GelMA composite conductive hydrogel, comprising the following steps: Preparing a dual-network hydrogel: GelMA is dissolved in PBS solution to prepare a solution, a photoinitiator is added to obtain a GelMA solution, which is then mixed with a silk fibroin solution. Glutaraldehyde is added and the mixture is stirred until homogeneous to obtain a prepolymer mixture. The prepolymer mixture is then irradiated under ultraviolet light and dried at a constant temperature to obtain a dual-network hydrogel; Preparing a silk fibroin-GelMA composite conductive hydrogel: A pyrrole aqueous solution and an ammonium persulfate aqueous solution are prepared. The dual-network hydrogel is first immersed in the ammonium persulfate aqueous solution, allowed to stand, and then transferred to… The mixture is impregnated in a pyrrole aqueous solution, then transferred to deionized water to stop the reaction, and dried to obtain a silk fibroin-GelMA composite conductive hydrogel. The silk fibroin-GelMA composite conductive hydrogel obtained in this way has the best mechanical properties, which match the mechanical properties of nerve tissue. It is suitable for the construction of nerve tissue engineering scaffolds and has a suitable conductivity, reaching the ideal conductivity range of nerve tissue, thereby promoting nerve regeneration. At the same time, the swelling rate meets the requirements of nerve tissue, and it can avoid damage and destruction to surrounding tissues during in vivo use. This application also provides a silk fibroin-GelMA composite conductive hydrogel obtained by this preparation method. Attached Figure Description

[0016] Figure 1 Microstructure of polypyrrole in Example 1; Figure 2 Stress-strain curves of hydrogels in Examples 1, 2, and 3; Figure 3 Swelling rates of hydrogels in Examples 1, 2, and 3. Detailed Implementation

[0017] This invention provides a method for preparing a silk fibroin-GelMA composite conductive hydrogel, which specifically includes the following steps.

[0018] S1: Preparation of a dual-network hydrogel; GelMA was dissolved in PBS to prepare a solution with a concentration of 10±1% (w / v), and Irgacure 2959 photoinitiator was added at a mass ratio of 1.5±0.1% (w / v) to the system volume to obtain the GelMA solution system. Then, it was mixed with a silk fibroin solution with a concentration of 10±1% at a volume ratio of 5:5±1. Glutaraldehyde was added, with the mass ratio of silk fibroin to glutaraldehyde being 1:(0.1±0.01). After mixing evenly, a prepolymer mixture was obtained. The prepolymer mixture was irradiated under ultraviolet light and dried at a constant temperature to obtain a double-network hydrogel.

[0019] S2: Preparation of silk fibroin-GelMA composite conductive hydrogel; Prepare a pyrrole aqueous solution with a concentration of 0.8%-1.2% and a 1±0.1 M ammonium persulfate aqueous solution. Immerse the double network hydrogel in the ammonium persulfate aqueous solution for 30-90 min, let it stand, transfer it to the pyrrole aqueous solution for 30-60 min, then transfer it to deionized water to stop the reaction, and dry it to obtain the silk fibroin-GelMA composite conductive hydrogel.

[0020] Specifically, GelMA can be obtained in the following ways: Gelatin powder was dissolved in PBS and stirred in a water bath until completely dissolved to obtain a gelatin solution. Methacrylic anhydride was added dropwise to the gelatin solution and stirred. Then PBS was added, dialyzed, centrifuged, and the supernatant was collected. The supernatant was stored at low temperature or freeze-dried to obtain methacrylic esterified gelatin (GelMA).

[0021] Silk fibroin solutions can be obtained in the following ways: Silk degumming: Heat deionized water to boiling, add Na2CO3, and after it is completely dissolved, put raw silk into it and degumme it under boiling conditions. Then wash and dry to obtain silk fibroin fiber.

[0022] Dissolution and dialysis of silk fibroin: The silk fibroin fibers were dissolved in 9.3±0.2 M lithium bromide solution at a bath ratio of (2.7±0.2):10. After complete dissolution, the solution was cooled to room temperature, then placed in a dialysis bag and sealed. The lithium bromide was removed by dialysis, and the solution was centrifuged to obtain the silk fibroin solution.

[0023] The preparation method of the silk fibroin-GelMA composite conductive hydrogel of this application is further described below through specific embodiments.

[0024] Example 1: S11: Preparation of a dual-network hydrogel; GelMA was dissolved in PBS to prepare a 10% (w / v) solution. Irgacure 2959 photoinitiator was added at a mass ratio of 1.5% (w / v) to the system volume to obtain the GelMA solution. Then, it was mixed with a 10% silk fibroin solution at a volume ratio of 5:5. Glutaraldehyde with a mass ratio of silk fibroin to glutaraldehyde of 1:0.1 was added, and the mixture was shaken and mixed evenly to obtain a prepolymer mixture. The prepolymer mixture was irradiated under ultraviolet light at a wavelength of 365 nm for 15 min, and then placed in a constant temperature drying oven at 37℃ until the reaction was complete to obtain a double-network hydrogel.

[0025] S12: Preparation of silk fibroin-GelMA composite conductive hydrogel; Prepare a 0.8% pyrrole aqueous solution and a 1M ammonium persulfate aqueous solution. Immerse the double-network hydrogel in the 1M ammonium persulfate aqueous solution for 90 min, then place it in a glass dish and let it stand for 30 min. Transfer it to the pyrrole aqueous solution and immerse it for 30 min. Then transfer it to deionized water for 30 min to stop the reaction and clean off any excess aggregates on the surface. Wipe off the moisture and dry it in a 60℃ oven for 10 min to obtain the silk fibroin-GelMA composite conductive hydrogel.

[0026] Meanwhile, methacrylated gelatin (GelMA) was prepared using the following method: S101: Preparation of methacrylated gelatin (GelMA): In this embodiment, GelMA was prepared as follows: 10 g of gelatin powder was dissolved in 100 mL of PBS solution and allowed to swell at room temperature for 1 h. The solution was then stirred in a 60°C constant temperature water bath until completely dissolved to form a gelatin solution. 8 mL of methacrylic anhydride was added dropwise to the gelatin solution at a rate of 1 mL / min. The solution was stirred vigorously at 50°C for 2 h. Then, 200 mL of PBS solution at 50°C was added to obtain an initial solution. Subsequently, the initial solution was dialyzed with 5 times the amount of deionized water at room temperature for 5-7 days, with the dialyzing water being changed every 4 h. After the initial solution was dialyzed, the dialysate was centrifuged at 3000 rpm for 10 min, and the supernatant was collected and stored at 4°C in the dark for 7 days or freeze-dried for 3 days to obtain GelMA.

[0027] Silk fibroin solution was prepared using the following method: S102: Preparation of silk fibroin solution: Silk degumming: Heat 10 L of deionized water to boiling, add 21.2 g of anhydrous Na2CO3, and after it is completely dissolved, weigh 25 g of raw silkworm silk and put it into the solution. Degumming is carried out under boiling conditions for 30 min. After removing the silk, wash it five times with deionized water to remove residual sericin. After loosening the silk, dry it in an oven at 60 ℃ to obtain fibroin fiber.

[0028] Dissolution and dialysis of silk fibroin: Silk fibroin was dissolved in 9.3 M lithium bromide solution at a bath ratio of 2.7:10 and dissolved in an oven at 60 °C for 4-5 h. After complete dissolution, it was cooled to room temperature and then sealed in a dialysis bag with a molecular weight cutoff of 3500 Da. The solution was dialyzed with deionized water for three days to remove lithium bromide and obtain silk fibroin dialysis solution. The water was changed every 1 h on the first day and every 2 h on the following two days. The silk fibroin dialysis solution was then centrifuged at 9000 r / min for 20 min twice to remove impurities and obtain silk fibroin solution.

[0029] Furthermore, the silk fibroin solution can be stored at 4°C for later use.

[0030] Example 2: In step S12, the soaking time for ammonium persulfate aqueous solution is 60 min, the soaking time for pyrrole aqueous solution is 30 min, and the rest is the same as in Example 1.

[0031] Example 3: In step S12, the soaking time for ammonium persulfate aqueous solution is 90 min, the soaking time for pyrrole aqueous solution is 45 min, and the other steps are the same as in Example 1.

[0032] Example 4: In step S12, the soaking time for ammonium persulfate aqueous solution is 30 min, and the soaking time for pyrrole aqueous solution is 60 min, and the rest is the same as in Example 1.

[0033] Example 5: In step S12, the concentration of the pyrrole aqueous solution is 1.2%, the soaking time of the ammonium persulfate aqueous solution is 90 min, the soaking time of the pyrrole aqueous solution is 30 min, and the rest is the same as in Example 1.

[0034] Example 6: In step S12, the concentration of the pyrrole aqueous solution is 1.2%, the soaking time of the ammonium persulfate aqueous solution is 30 min, the soaking time of the pyrrole aqueous solution is 45 min, and the rest is the same as in Example 1.

[0035] Comparative Example 1: GelMA prepared in step S101.

[0036] Comparative Example 2: Silk fibroin hydrogels were formed by cryogenic gelation of the silk fibroin solution prepared in step S102.

[0037] Comparative Example 3: The dual-network hydrogel prepared in step S11.

[0038] Comparative Example 4: In step S12, the concentration of the pyrrole aqueous solution is 0.4%, the impregnation time of the ammonium persulfate aqueous solution is 30 min, the impregnation time of the pyrrole aqueous solution is 30 min, and the other steps are the same as those in Example 1 for preparing the silk fibroin-GelMA composite conductive hydrogel.

[0039] Comparative Example 5: In step S12, the concentration of the pyrrole aqueous solution is 0.4%, the impregnation time of the ammonium persulfate aqueous solution is 60 min, the impregnation time of the pyrrole aqueous solution is 45 min, and the other steps are the same as those in Example 1 for preparing the silk fibroin-GelMA composite conductive hydrogel.

[0040] Comparative Example 6: In step S12, the concentration of the pyrrole aqueous solution is 0.4%, the impregnation time of the ammonium persulfate aqueous solution is 90 min, the impregnation time of the pyrrole aqueous solution is 60 min, and the other steps are the same as those in Example 1 for preparing the silk fibroin-GelMA composite conductive hydrogel.

[0041] Comparative Example 7: In step S12, the concentration of the pyrrole aqueous solution is 1.2%, the impregnation time of the ammonium persulfate aqueous solution is 60 min, the impregnation time of the pyrrole aqueous solution is 60 min, and the other steps are the same as those in Example 1 for preparing the silk fibroin-GelMA composite conductive hydrogel.

[0042] The microstructure of the polypyrrole in Example 1 was analyzed, such as... Figure 1 As shown, the diameter of polypyrrole is about 0.1 μm, which allows it to be well dispersed inside the hydrogel.

[0043] The mechanical properties and swelling rates of the hydrogels prepared in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 were tested.

[0044] (1) Mechanical properties Please refer to this as well. Figure 2 The mechanical property test results of Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 are as follows: The applicant's research found that the concentration of photoinitiator and the volume ratio of silk fibroin solution to GelMA solution have a significant impact on the mechanical properties of the gel of the present invention. With the increase of photoinitiator content, the number of free radicals generated by the photoinitiator increases, the number of polymerization sites formed in the system increases, resulting in longer and more stable and robust macromolecular chains in the photocatalytically formed network, and an increase in the degree of crosslinking of the GelMA network, thereby enhancing the mechanical properties that can be withstood. In the hydrogel of the present invention, its mechanical properties are jointly played by silk fibroin and GelMA. The GelMA network is mainly photocatalyzed, while the silk fibroin network is mainly crosslinked by glutaraldehyde. The above test results also show that the increase of glutaraldehyde is beneficial to the improvement of the degree of crosslinking of the silk fibroin network, resulting in an increase in the mechanical properties of the gel. For the hydrogel of Comparative Example 2, the chemically cross-linked pure silk fibroin hydrogel has high strength because the active groups react with the groups of the cross-linking agent molecules to form a stable covalent cross-linked network. However, due to the restriction of the movement of silk fibroin polymer molecules by its internal β-sheet, the pure silk fibroin hydrogel is hard and brittle, with insufficient extensibility and flexibility. For the hydrogel of Comparative Example 1, the photocrosslinking has a faster crosslinking speed and milder crosslinking reaction conditions, so the prepared GelMA hydrogel has good elasticity. In the hydrogel of this invention, the two are blended in a certain proportion to form a double-network hydrogel, and the properties are complementary. The formed double-network hydrogel has a certain elasticity and can meet the mechanical properties required for nerve regeneration applications. At the same time, after introducing the conductive substance polypyrrole, the conductive substance enters the hydrogel to form a conductive network, which increases the effective network inside the silk fibroin-GelMA composite conductive hydrogel of this application and enhances the intermolecular forces, resulting in a further improvement in the mechanical properties of the silk fibroin-GelMA composite conductive hydrogel. Its maximum compressive strength reaches 127.04±23.42 kPa, which is comparable to the mechanical properties of nerve tissue (0.1-10). 3 It is compatible with the kPa) and suitable for the construction of neural tissue engineering scaffolds.

[0045] (2) Swelling properties Please refer to this as well. Figure 3 One of the most significant characteristics of hydrogels is their water-absorbing and swelling properties. This property helps them absorb and transport nutrients and metabolites within tissues. Figure 3 The swelling properties of different hydrogels in PBS buffer (pH=7.4) were shown in the figure, determined by gravimetric method.

[0046] As shown in the figures, the swelling rate of the GelMA hydrogel in Comparative Example 1 can reach approximately 500%-600%. Its molecular chains contain numerous hydrophilic groups, which easily attract water molecules. The study found that when the swelling rate reaches around 500%, the GelMA hydrogel breaks down. As water enters, the internal space of the gel is filled, and the poor mechanical properties of the GelMA hydrogel lead to the destruction of its internal network structure. The silk fibroin hydrogel in Comparative Example 2 and the double-network hydrogel in Comparative Example 3 did not show structural damage and both reached swelling equilibrium at approximately 9 hours. The silk fibroin hydrogel in Comparative Example 2 has a maximum swelling rate of 208.15%. Its molecular chains also contain many hydrophilic groups, but some amino groups form chemical cross-links under the action of glutaraldehyde, increasing the degree of network cross-linking and making it difficult for water molecules to enter the internal structure of the gel, thus reducing the swelling rate. Simultaneously, the β-sheet structure and internal hydrogen bonds of silk fibroin cause the molecular chains to entangle with each other, making the gel structure compact and further reducing the swelling rate. The maximum swelling rate of the dual-network hydrogel in Comparative Example 3 was 344.34%, which was between that of Comparative Example 1 and Comparative Example 2. In contrast, the maximum swelling rate of the silk fibroin-GelMA composite conductive hydrogel of this application was 118.34%. Due to the introduction of polypyrrole, a conductive network was further formed inside the hydrogel, resulting in a denser space and smaller pores in the three-dimensional network structure, thus reducing the swelling rate of the hydrogel. Simultaneously, the larger polypyrrole particles formed by in-situ polymerization aggregated within the hydrogel, reducing its water absorption capacity. Therefore, the silk fibroin-GelMA composite conductive hydrogel of this application, when used in vivo, can meet the requirements of nerve tissue while avoiding damage and destruction to surrounding tissues caused by excessive swelling.

[0047] (3) Electrical conductivity The conductivity of Examples 1-6 and Comparative Examples 4-7 was tested. Electrode sheets were loaded at both ends of the conductive hydrogel, and the resistance was measured using a multimeter. The conductivity was calculated according to the following formula, where L is the sample length, R is the sample resistance, and S is the sample cross-sectional area.

[0048] The specific results are shown in the table below: The test results above show that, in Examples 1-6, the conductivity of the silk fibroin-GelMA composite conductive hydrogel can form a good conductive pathway, reaching the ideal conductivity range for nerve tissue (3.4 × 10⁻⁶). -4 ~4×10 -1 (S / cm), thereby promoting nerve regeneration.

[0049] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for preparing a silk fibroin-GelMA composite conductive hydrogel, characterized in that, Includes the following steps: S1: Preparation of dual-network hydrogel: GelMA was dissolved in PBS solution to prepare a solution with a mass-volume concentration of 10±1%. A photoinitiator was added, with the mass-volume ratio of the photoinitiator to the system volume being 1.5±0.1%, to obtain a GelMA solution. Then, it was mixed with a silk fibroin solution with a concentration of 10±1% at a volume ratio of 5:(5±1). Glutaraldehyde was added, with the mass ratio of silk fibroin to glutaraldehyde being 1:(0.1±0.01). The mixture was mixed evenly to obtain a prepolymer mixture. The prepolymer mixture was irradiated under ultraviolet light and dried at a constant temperature to obtain a dual-network hydrogel. S2: Preparation of silk fibroin-GelMA composite conductive hydrogel: Prepare a pyrrole aqueous solution with a concentration of 0.8%-1.0% and a 1±0.1 M ammonium persulfate aqueous solution. Immerse the double network hydrogel in the ammonium persulfate aqueous solution for 60-90 min, let it stand, transfer it to the pyrrole aqueous solution for 30-45 min, then transfer it to deionized water to stop the reaction, and dry it to obtain the silk fibroin-GelMA composite conductive hydrogel.

2. The preparation method of the silk fibroin-GelMA composite conductive hydrogel as described in claim 1, characterized in that, GelMA was obtained as follows: gelatin powder was dissolved in PBS and stirred in a water bath until completely dissolved to obtain a gelatin solution. Methacrylic anhydride was added dropwise to the gelatin solution and stirred. Then PBS was added, dialyzed, centrifuged, and the supernatant was collected and stored at low temperature or freeze-dried to obtain GelMA.

3. The preparation method of the silk fibroin-GelMA composite conductive hydrogel as described in claim 1, characterized in that, The silk fibroin solution was obtained using the following method: Silk degumming: Heat deionized water to boiling, add Na2CO3, and after it is completely dissolved, put raw silk into it. Degumming is carried out under boiling conditions, followed by washing and drying to obtain silk fibroin fibers; Dissolution and dialysis of silk fibroin: The silk fibroin fibers were dissolved in 9.3±0.2 M lithium bromide solution at a bath ratio of (2.7±0.2):

10. After complete dissolution, the solution was cooled to room temperature, then placed in a dialysis bag and sealed. The lithium bromide was removed by dialysis, and the solution was centrifuged to obtain the silk fibroin solution.

4. The preparation method of the silk fibroin-GelMA composite conductive hydrogel as described in claim 1, characterized in that, In step S1, the mass ratio of silk fibroin to glutaraldehyde is 1:0.1, the volume ratio of silk fibroin solution to GelMA solution is 5:5, and the mass ratio of photoinitiator to system volume is 1.5%.

5. The preparation method of the silk fibroin-GelMA composite conductive hydrogel as described in claim 4, characterized in that, In step S2, the concentration of the pyrrole aqueous solution is 0.8%, the immersion time in the ammonium persulfate solution is 90 min, and the immersion time in the pyrrole solution is 30 min.

6. The preparation method of the silk fibroin-GelMA composite conductive hydrogel as described in claim 4, characterized in that, In step S2, the standing time specifically refers to standing in a glass dish for 30 minutes, the transfer to deionized water to stop the reaction specifically refers to transferring to deionized water for 30 minutes to stop the reaction and cleaning off any excess aggregates on the surface, and the drying time refers to drying in a 60°C oven for 10 minutes.

7. The preparation method of the silk fibroin-GelMA composite conductive hydrogel as described in claim 1, characterized in that, The photoinitiator is Irgacure 2959, the ultraviolet light is 365 nm ultraviolet light, and the irradiation time is 15-30 min.

8. A silk fibroin-GelMA composite conductive hydrogel, characterized in that, Prepared using the preparation method described in claim 1.

9. The silk fibroin-GelMA composite conductive hydrogel as described in claim 8, characterized in that, The conductivity of the silk fibroin-GelMA composite conductive hydrogel is greater than or equal to 0.49 × 10⁻⁶. -2 S / cm.

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