Conductive hydrogel for neural electrodes and methods of making and using the same

Abstract

The application provides a conductive hydrogel for a neural electrode and a preparation method and application thereof, the conductive hydrogel comprising a polymer three-dimensional network, the hydrogel being doped with a conductive polymer and a Lewis acid inside; the conductive polymer is phase-separated to form a conductive network under the action of the Lewis acid. The conductive hydrogel has excellent conductive performance and mechanical performance, and also has good biocompatibility.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of neural electrodes, and relates to a conductive hydrogel for neural electrodes and a preparation method and application thereof. BACKGROUND

[0002] Flexible neural electrodes can reduce post-implantation tissue damage and inflammatory response due to their high matching degree with neural tissue and the ability to adapt to brain tissue micro-movement, thus having a wide application prospect in the field of neural signal detection and helping to achieve more stable and long-term neural recording. Conductive hydrogels for flexible neural electrodes have become a potential alternative to traditional metal neural electrodes in the field of brain-computer interface bioelectronic interfaces due to their similarity to biological tissue (high water content, softness) and conductivity. Among them, conductive polymer hydrogels (conductive hydrogels based on conductive polymers) show a series of advantages compared with other conductive hydrogels based on metals (such as silver, gold, platinum) or carbon nanomaterials (such as carbon nanotubes, graphene and its derivatives), including good electrical performance, physiological environment stability and biocompatibility.

[0003] Although certain progress has been made in hydrogels simulating the mechanical properties of biological tissue, there are still challenges in the research of conductive polymer hydrogels with good mechanical properties. Existing tough conductive polymer hydrogels are usually prepared by mixing or polymerizing conductive polymers in a tough hydrogel matrix. Due to the low connectivity between the conductive phases in the hydrogel and / or the high stiffness and low water content different from biological tissue, they show low electrical conductivity. High electrical conductivity is usually achieved by increasing the content of conductive polymers (for example, pure conductive polymer hydrogels), which greatly reduces the mechanical properties of the hydrogels, limiting their application in flexible neural electrodes. This is because flexible neural electrodes need to have good mechanical and electrical properties at the same time to well reduce the inflammatory response caused by the neural electrodes as a foreign body and improve the signal-to-noise ratio of recorded neural electrical signals.

[0004] Therefore, it is very important to develop a conductive hydrogel that has both tissue-like mechanical properties and high electrical conductivity. SUMMARY

[0005] To solve the technical problems existing in the prior art, the present application provides a conductive hydrogel for neural electrodes and a preparation method and application thereof, which has excellent electrical and mechanical properties and good biocompatibility.

[0006] To achieve the above technical effects, the present application adopts the following technical solutions:

[0007] One of the purposes of the present application is to provide a conductive hydrogel for a neural electrode, which comprises a polymer three-dimensional network, and a conductive polymer and a Lewis acid are doped inside the hydrogel;

[0008] The conductive polymer is phase-separated to form a conductive network under the action of the Lewis acid.

[0009] As a preferred technical solution of the present application, the conductive polymer is poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid).

[0010] As a preferred technical solution of the present application, the Lewis acid comprises any one or a combination of at least two of sodium chloride, magnesium chloride, indium chloride, nickel chloride or iron chloride.

[0011] As a preferred technical solution of the present application, the polymer three-dimensional network is obtained by polymerization of an unsaturated base-sulfobetaine monomer and a crosslinking agent.

[0012] As a preferred technical solution of the present application, the unsaturated base-sulfobetaine comprises methacryloyl ethyl sulfobetaine.

[0013] And / or, the crosslinking agent comprises N,N'-methylene bisacrylamide.

[0014] The second purpose of the present application is to provide a preparation method of the conductive hydrogel for a neural electrode provided in the first purpose, which comprises:

[0015] Mixing the polymer monomer required to form the polymer three-dimensional network, a photoinitiator and a conductive polymer solution to perform a photopolymerization reaction to obtain a template hydrogel;

[0016] Soaking the template hydrogel in the aqueous Lewis acid solution to obtain the conductive hydrogel.

[0017] As a preferred technical solution of the present application, the mass fraction of the conductive polymer in the conductive polymer solution is 1-1.3%.

[0018] And / or, the mass ratio of the unsaturated base-sulfobetaine to the conductive polymer is 20-120:1.

[0019] And / or, the mass ratio of the unsaturated base-sulfobetaine to the crosslinking agent is 500-1000:1.

[0020] And / or, the mass ratio of the unsaturated base-sulfobetaine to the photoinitiator is 5000-10000:1.

[0021] As a preferred technical solution of the present application, the mass concentration of the aqueous Lewis acid solution is 10-30%.

[0022] As a preferred technical scheme of the present application, the template hydrogel is soaked in the aqueous solution of the Lewis acid for 2-4 hours in anhydrous ethanol before being soaked in the aqueous solution of the Lewis acid.

[0023] And / or, the template hydrogel is soaked in the aqueous solution of the Lewis acid for 48-72 hours in a buffer solution with a pH value of 7-7.4 after being soaked in the aqueous solution of the Lewis acid.

[0024] A third object of the present application is to provide an application of the conductive hydrogel for a neural electrode for the preparation of a neural electrode for monitoring a brain cortex field potential signal.

[0025] Compared with the prior art, the present application has at least the following beneficial effects:

[0026] (1) The present application provides a conductive hydrogel for a neural electrode, a preparation method and an application thereof, and the conductive hydrogel has excellent electrical conductivity and mechanical properties, the electrical conductivity of the conductive hydrogel is 3.2-9.2 S / m, and the Young's modulus can reach 16.85 kPa.

[0027] (2) The present application provides a conductive hydrogel for a neural electrode, a preparation method and an application thereof, and the conductive hydrogel has good biocompatibility.

[0028] (3) The present application provides a conductive hydrogel for a neural electrode, a preparation method and an application thereof, and the flexible neural electrode prepared from the conductive hydrogel can be used for recording a brain cortex LFP signal, and the signal-to-noise ratio can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The flowchart of the preparation method of the conductive hydrogel provided in the detailed description of the present application is shown.

[0030] Figure 2 The tensile stress-strain curve of the conductive hydrogel prepared in Example 4 of the present application is shown.

[0031] Figure 3 The Young's modulus data graph of the conductive hydrogel prepared in Examples 1-6 of the present application is shown.

[0032] Figure 4 The scanning electron microscope (SEM) graph of the conductive hydrogel prepared in Example 4 of the present application after freeze-drying is shown.

[0033] Figure 5 The conductivity graph of the hydrogel treated by different types and concentrations of Lewis acid solutions prepared in Examples 4 and 7-11 of the present application is shown.

[0034] Figure 6The conductivity change diagram of the conductive hydrogel prepared in the embodiment 1-6 immersed in the phosphate buffer for 14 days.

[0035] Figure 7 The impedance spectrum diagram of the gold electrode modified by the conductive hydrogel prepared in the embodiment 4 at different frequencies.

[0036] Figure 8 The impedance change diagram of the gold electrode modified by the conductive hydrogel prepared in the embodiment 4 at the frequency of 1000 Hz immersed in the phosphate buffer for 14 days.

[0037] Figure 9 The live and dead staining contrast diagram of the mouse hippocampal neuron cell (HT22) cells cultured by using the culture medium immersed by the conductive hydrogel prepared in the embodiment 4 and the culture medium of the control group without any treatment.

[0038] Figure 10 The contrast diagram of the long-term monitoring of the normal rat brain cortex LFP signal by using the conductive hydrogel-polyimide film electrode prepared in the embodiment 4 and the pure polyimide film electrode.

[0039] The application will be further described in detail below. However, the following examples are only simple examples of the application and do not represent or limit the protection scope of the application, and the protection scope of the application is subject to the claims. DETAILED DESCRIPTION

[0040] The technical scheme of the application will be further described below through the specific embodiments.

[0041] The specific embodiment of the application provides a conductive hydrogel for a neural electrode, which comprises a polymer three-dimensional network, and a conductive polymer and a Lewis acid are doped in the interior of the hydrogel.

[0042] The conductive polymer is phase-separated to form a conductive network under the action of the Lewis acid.

[0043] In the application, the introduced Lewis acid cation interacts with the negatively charged conductive polymer, so that the conductive polymer is phase-separated, and the conductive polymer forms a conductive network for further connection, so as to improve the conductivity of the hydrogel.

[0044] In one specific embodiment of the application, the conductive polymer is poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) (PEDOT:PSS). The PEDOT and PSS are phase-separated under the action of the conductive polymer, and the PEDOT conductive network is further connected.

[0045] In one embodiment of the present application, the Lewis acid includes any one or a combination of at least two of sodium chloride, magnesium chloride, indium chloride, nickel chloride, or iron chloride.

[0046] In one embodiment of the present application, the polymer three-dimensional network is obtained by polymerization of the unsaturated group-sulfobetaine monomer and the crosslinking agent.

[0047] In one embodiment of the present application, the unsaturated group-sulfobetaine includes methacryloyl ethyl sulfobetaine (SBMA).

[0048] In one embodiment of the present application, the crosslinking agent includes N,N'-methylene bisacrylamide (MBAA).

[0049] In the present application, due to the super-hydrophilicity of the zwitterionic polymer polymethacrylic acid sulfobetaine, the conductivity of the conductive hydrogel is further improved, and the conductive hydrogel also has low Young's modulus and good biocompatibility.

[0050] The embodiment of the present application provides a preparation method of a conductive hydrogel for a neural electrode, and the preparation method comprises the following steps:

[0051] Mixing polymer monomers required for forming the polymer three-dimensional network, a photoinitiator, and a conductive polymer solution to perform a photopolymerization reaction to obtain a template hydrogel;

[0052] Soaking the template hydrogel in the aqueous Lewis acid solution to obtain the conductive hydrogel.

[0053] In one embodiment of the present application, the mass fraction of the conductive polymer in the conductive polymer solution is 1-1.3%, such as 1%, 1.1%, 1.2%, or 1.3%, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0054] In one embodiment of the present application, the mass ratio of the unsaturated group-sulfobetaine to the conductive polymer is 20-120:1, such as 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, 90:1, 100:1, 110:1, or 120:1, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0055] In one embodiment of the present application, the mass ratio of the unsaturated group-sulfobetaine to the crosslinking agent is 500-1000:1, such as 500:1, 600:1, 700:1, 800:1, 900:1, or 1000:1, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0056] In one embodiment of the present application, the mass ratio of the unsaturated group-sulfobetaine to the photoinitiator is 5000-10000:1, such as 5000:1, 6000:1, 7000:1, 8000:1, 9000:1, or 10000:1, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0057] In one embodiment of the present application, the photoinitiator is preferably 2-hydroxy-2-methyl-1-phenylpropanone (1173).

[0058] In one embodiment of the present application, the polymer monomer, photoinitiator, and conductive polymer solution required for the three-dimensional network of the polymer are mixed under light-proof conditions for 1-2 hours.

[0059] In one embodiment of the present application, the photopolymerization reaction is carried out under ultraviolet light irradiation, and the reaction time is 1-1.5 hours.

[0060] In one embodiment of the present application, the wavelength of the ultraviolet light irradiation can be 302 nm.

[0061] In one embodiment of the present application, the mass concentration of the aqueous Lewis acid solution is 10-30%, such as 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, or 30%, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0062] In one embodiment of the present application, the template hydrogel is soaked in the aqueous Lewis acid solution for 72-96 hours, such as 72 hours, 76 hours, 80 hours, 84 hours, 88 hours, 92 hours, or 96 hours, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0063] In one embodiment of the present application, before the template hydrogel is soaked in the aqueous Lewis acid solution, it is soaked in anhydrous ethanol solution for 2-4 hours, such as 2 hours, 2.2 hours, 2.5 hours, 2.8 hours, 3 hours, 3.2 hours, 3.5 hours, 3.8 hours, or 4 hours, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0064] In one embodiment of the present application, after the template hydrogel is soaked in the aqueous Lewis acid solution, it is soaked in a buffer solution with a pH value of 7-7.4 for 48-72 hours. The pH value can be 7, 7.1, 7.2, 7.3, or 7.4, and the soaking time can be 48 hours, 54 hours, 60 hours, 66 hours, or 72 hours, but is not limited to the listed values, and other values not listed in the range are also applicable.

[0065] To better illustrate the present application, facilitate understanding of the technical solutions of the present application, the typical but non-limiting embodiments of the present application are as follows:

[0066] Embodiment 1

[0067] The present embodiment provides a preparation method of a conductive hydrogel for a neural electrode, the flowchart of which is shown as Figure 1 The preparation method comprises:

[0068] 0.4g of SBMA monomer, 0.44mg of MBAA crosslinking agent and 0.047mg of photoinitiator 1173 are dissolved in 2mL of PEDOT:PSS (1wt%) solution, stirred at room temperature for 1h in the dark, and then cured under 302nm ultraviolet light for 1h to obtain a template hydrogel;

[0069] The template hydrogel is sequentially immersed in anhydrous ethanol for 4h, in a 30wt% NaCl solution for 96h, and in a pH 7-7.4 phosphate buffer for 48h to obtain a conductive hydrogel with a mass ratio of SBMA monomer to PEDOT:PSS of 20:1.

[0070] Embodiment 2

[0071] The present embodiment provides a preparation method of a conductive hydrogel for a neural electrode, the preparation method comprising:

[0072] 0.8g of SBMA monomer, 0.88mg of MBAA crosslinking agent and 0.094mg of photoinitiator 1173 are dissolved in 2mL of PEDOT:PSS (1wt%) solution, stirred at room temperature for 1h in the dark, and then cured under 302nm ultraviolet light for 1h to obtain a template hydrogel;

[0073] The template hydrogel is sequentially immersed in anhydrous ethanol for 4h, in a 30wt% NaCl solution for 96h, and in a pH 7-7.4 phosphate buffer for 48h to obtain a conductive hydrogel with a mass ratio of SBMA monomer to PEDOT:PSS of 40:1.

[0074] Embodiment 3

[0075] The present embodiment provides a preparation method of a conductive hydrogel for a neural electrode, the preparation method comprising:

[0076] 1.2g of SBMA monomer, 1.32mg of MBAA crosslinking agent and 0.141mg of photoinitiator 1173 are dissolved in 2mL of PEDOT:PSS (1wt%) solution, stirred at room temperature for 1h in the dark, and then cured under 302nm ultraviolet light for 1h to obtain a template hydrogel;

[0077] The template hydrogel is sequentially soaked in anhydrous ethanol for 4 h, soaked in a 30 wt% NaCl solution for 96 h, and soaked in a pH 7-7.4 phosphate buffer for 48 h to obtain a conductive hydrogel with a mass ratio of SBMA monomer to PEDOT:PSS of 60:1.

[0078] Example 4

[0079] The embodiment provides a preparation method of a conductive hydrogel for a neural electrode, and the preparation method comprises the following steps:

[0080] 1.6 g of SBMA monomer, 0.88 mg of MBAA crosslinking agent, and 0.094 mg of a photoinitiator 1173 are dissolved in 2 mL of a PEDOT:PSS (1 wt%) solution, stirred at room temperature and in the dark for 1 h, and then cured under 302 nm ultraviolet light for 1 h to obtain a template hydrogel;

[0081] The template hydrogel is sequentially soaked in anhydrous ethanol for 4 h, soaked in a 30 wt% NaCl solution for 96 h, and soaked in a pH 7-7.4 phosphate buffer for 48 h to obtain a conductive hydrogel with a mass ratio of SBMA monomer to PEDOT:PSS of 80:1.

[0082] Example 5

[0083] The embodiment provides a preparation method of a conductive hydrogel for a neural electrode, and the preparation method comprises the following steps:

[0084] 2.0 g of SBMA monomer, 1.1 mg of MBAA crosslinking agent, and 0.118 mg of a photoinitiator 1173 are dissolved in 2 mL of a PEDOT:PSS (1 wt%) solution, stirred at room temperature and in the dark for 1 h, and then cured under 302 nm ultraviolet light for 1 h to obtain a template hydrogel;

[0085] The template hydrogel is sequentially soaked in anhydrous ethanol for 4 h, soaked in a 30 wt% NaCl solution for 96 h, and soaked in a pH 7-7.4 phosphate buffer for 48 h to obtain a conductive hydrogel with a mass ratio of SBMA monomer to PEDOT:PSS of 100:1.

[0086] Example 6

[0087] The embodiment provides a preparation method of a conductive hydrogel for a neural electrode, and the preparation method comprises the following steps:

[0088] 2.4 g of SBMA monomer, 1.32 mg of MBAA crosslinking agent, and 0.141 mg of a photoinitiator 1173 are dissolved in 2 mL of a PEDOT:PSS (1 wt%) solution, stirred at room temperature and in the dark for 1 h, and then cured under 302 nm ultraviolet light for 1 h to obtain a template hydrogel;

[0089] The template hydrogel was sequentially soaked in anhydrous ethanol for 4 h, 30 wt% NaCl solution for 96 h, and pH 7-7.4 phosphate buffer for 48 h, to obtain a conductive hydrogel with a mass ratio of SBMA monomer to PEDOT:PSS of 120:1.

[0090] Example 7

[0091] This example provides a preparation method of a conductive hydrogel for a neural electrode, which is identical to that of Example 4 except that the concentration of sodium chloride is replaced by 0 wt%, 10 wt%, and 20 wt%.

[0092] Example 8

[0093] This example provides a preparation method of a conductive hydrogel for a neural electrode, which is identical to that of Example 4 except that sodium chloride is replaced by magnesium chloride, and the concentration of magnesium chloride is 0 wt%, 10 wt%, 20 wt%, and 30 wt%.

[0094] Example 9

[0095] This example provides a preparation method of a conductive hydrogel for a neural electrode, which is identical to that of Example 8 except that magnesium chloride is replaced by indium chloride.

[0096] Example 10

[0097] This example provides a preparation method of a conductive hydrogel for a neural electrode, which is identical to that of Example 8 except that magnesium chloride is replaced by nickel chloride.

[0098] Example 11

[0099] This example provides a preparation method of a conductive hydrogel for a neural electrode, which is identical to that of Example 8 except that magnesium chloride is replaced by iron chloride.

[0100] Performance Test I

[0101] The tensile properties of the conductive hydrogel obtained in Example 4 were tested on a universal material tester 3365, and the tensile stress-strain curve was obtained as shown in FIG. 4. Figure 2 It can be seen that the hydrogel has good tensile properties, and the maximum elongation is greater than 170%.

[0102] Performance Test II

[0103] The tensile properties of the conductive hydrogels obtained in Examples 1-6 were tested on a universal material tester 3365, and the Young's modulus data were calculated from the tensile stress-strain curves as shown in FIG. 5. Figure 3As shown, it can be seen that the Young's modulus of the conductive hydrogel with SBMA monomer and PEDOT:PSS mass ratio of 80:1, 100:1 and 120:1 is lower, and the modulus is more matched with the brain tissue.

[0104] Performance test three

[0105] The internal structure of the conductive hydrogel obtained in Example 4 was tested on a field emission scanning electron microscope, and the operating method included:

[0106] The above prepared hydrogel was placed in liquid nitrogen, and then freeze-dried, 25 mA gold spraying for 3 min, and the scanning electron microscope was used to observe the microstructure of the hydrogel (as shown in Figure 4 As shown by the scanning electron microscope, the conductive hydrogel has a micro-porous structure.

[0107] Performance test four

[0108] The conductivity of the hydrogel treated by different kinds and concentrations of Lewis acid solutions provided in Examples 4 and 7-11 was tested by an ST2242 four-probe instrument, as shown in Figure 5 As shown, it can be seen that the conductivity of the hydrogel treated by 30% NaCl solution is the highest.

[0109] Performance test five

[0110] The conductivity change of the hydrogel with different mass ratios of SBMA monomer and PEDOT:PSS treated by 30% NaCl solution and immersed in phosphate buffer for 14 days was tested by an ST2242 four-probe instrument, as shown in Figure 6 As shown, the conductivity of the conductive hydrogel tends to be stable after the second day.

[0111] Performance test six

[0112] The change of impedance at different frequencies of the conductive hydrogel provided in Example 4 before and after modification was tested by an electrochemical workstation using a three-electrode system, in which the reference electrode was an Ag / AgCl electrode and the counter electrode was a platinum sheet electrode, and the final result was as shown in Figure 7 As shown, the impedance of the conductive hydrogel after modification is significantly reduced when the frequency is less than 10000.

[0113] Performance test seven

[0114] The change of impedance at 1000 Hz frequency of the gold electrode modified by the conductive hydrogel provided in Example 4 immersed in phosphate buffer for 14 days was continuously monitored by an electrochemical workstation, as shown in Figure 8 As shown, the impedance is basically stable.

[0115] Performance test eight

[0116] The dead / live cell staining method was used to determine the cell survival and cell proliferation of HT22 cells in the conductive hydrogel leaching medium in Example 4. The operation method includes:

[0117] The conductive hydrogel prepared in Example 4 was placed in 20 mL of culture medium and incubated for 24 h at 37°C. The culture medium after the hydrogel was then filtered with a filter to obtain a conductive hydrogel leaching medium. The culture medium without incubation was used as the control group.

[0118] HT22 cells were cultured in the two culture media for 1 day, then the culture medium was removed and washed three times with phosphate buffer. Cell activity was measured using a Live / Dead kit, and observed under a laser confocal microscope at excitation wavelengths of 488 / 561 nm. Live cells were stained with calcein to emit green fluorescence, while dead cells were stained with propidium iodide to emit red fluorescence.

[0119] like Figure 9 The cell survival in the conductive hydrogel group was similar to that in the control group, indicating that the conductive hydrogel had essentially no cytotoxicity and good biocompatibility.

[0120] Performance Test Nine

[0121] With the help of a stereotaxic device, a 5x5 mm cranial window was opened in the rat brain. A conductive hydrogel-polyimide film electrode or polyimide film electrode was attached to the cranial window and fixed with dental cement. After the electrode implantation process was completed, the LFP signal of the rat cerebral cortex could be monitored at the specified time using an electrophysiological instrument. The two-week long-term signal monitoring results are as follows. Figure 10 As shown, the signal-to-noise ratio of the signal measured by the electrode modified with the conductive hydrogel provided in Example 4 is higher than that of the unmodified electrode, and the polyimide film electrode modified with the conductive hydrogel can stably monitor the LFP signal within two weeks.

[0122] The applicant declares that the present invention is intended to illustrate the detailed structural features of the present invention through the above-described embodiments, but the present invention is not limited to the above-described detailed structural features. This does not mean that the present invention must rely on the above-described detailed structural features in order to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent replacements for selected components, additions of auxiliary components, and selection of specific embodiments, etc., fall within the scope of protection and disclosure of the present invention.

[0123] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0124] It should be noted that various technical features described in the above detailed description are capable of being combined in any suitable manner, and that the application is not limited to the specific combinations described in the above detailed description, which are provided for illustrative purposes only.

[0125] Furthermore, the various embodiments of the application can also be combined with each other, as long as it does not violate the spirit of the application, it should also be considered as disclosed by the present application.

Claims

1. A conductive hydrogel for neural electrodes, characterized in that: The conductive hydrogel comprises a three-dimensional polymer network, wherein the hydrogel is doped with a conductive polymer and a Lewis acid; The conductive polymer undergoes phase separation under the action of the Lewis acid to form a conductive network; The conductive polymer is poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid); The Lewis acid comprises any one or a combination of at least two of sodium chloride, magnesium chloride, indium chloride, nickel chloride or ferric chloride; The three-dimensional polymer network is obtained by polymerizing an unsaturated-sulfobetaine monomer and a cross-linking agent; The unsaturated-sulfobetaine monomer includes methacryloylethylsulfobetaine; The cross-linking agent includes N,N'-methylenebisacrylamide; The conductive hydrogel is prepared by the following preparation method: An unsaturated sulfobetaine monomer, a crosslinking agent, a photoinitiator and a conductive polymer solution are mixed and subjected to photopolymerization to obtain a template hydrogel; The template hydrogel is immersed in the Lewis acid aqueous solution to obtain the conductive hydrogel.

2. A method for preparing the conductive hydrogel for neural electrodes according to claim 1, characterized in that: The preparation method comprises: An unsaturated sulfobetaine monomer, a crosslinking agent, a photoinitiator and a conductive polymer solution are mixed and subjected to photopolymerization to obtain a template hydrogel; The template hydrogel is immersed in the Lewis acid aqueous solution to obtain the conductive hydrogel.

3. The preparation method according to claim 2, characterized in that The mass fraction of the conductive polymer in the conductive polymer solution is 1-1.3%; And / or, the mass ratio of the unsaturated-sulfobetaine monomer to the conductive polymer is 20-120:1; and / or, the mass ratio of the unsaturated-sulfobetaine monomer to the cross-linking agent is 500-1000:1; And / or, the mass ratio of the unsaturated-sulfobetaine monomer to the photoinitiator is 5000-10000:

1.

4. The preparation method according to claim 2, characterized in that The mass concentration of the Lewis acid aqueous solution is 10-30%.

5. The preparation method according to claim 2, characterized in that The template hydrogel is soaked in anhydrous ethanol for 2 to 4 hours before being soaked in the Lewis acid aqueous solution; And / or, after the template hydrogel is immersed in the Lewis acid aqueous solution, it is immersed in a buffer solution with a pH value of 7 to 7.4 for 48 to 72 hours.

6. A use of the conductive hydrogel for neural electrodes according to claim 1, characterized in that: The conductive hydrogel is used for preparing neural electrodes for monitoring cerebral cortical field potential signals.

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