Flexible PEDOT: PSS hydrogel fiber neural electrode array and preparation method and application thereof

Abstract

The invention discloses a flexible PEDOT: PSS hydrogel fiber neural electrode array and a preparation method and application thereof. The preparation method comprises the following steps: preparing PEDOT: PSS hydrogel conductive fiber as an electrode by adopting a wet spinning technology; and carrying out insulation treatment on the PEDOT: PSS hydrogel conductive fiber by adopting uracil grafted polyvinyl alcohol, and assembling the PEDOT: PSS hydrogel conductive fiber, so as to prepare the flexible PEDOT: PSS hydrogel fiber neural electrode array. The hydrogel fiber neural electrode array has a tissue-level modulus matched with neurons, a submicron adjustable geometric dimension, an ion-rich water-containing characteristic and an open three-dimensional topological structure, can effectively form a fusion symbiotic interface with brain tissues, and realizes long-term stable tracking of spike signals distinguished by single neurons; and a feasible information interaction tool is provided for a new generation of biocompatible brain-computer interface equipment.

Description

Technical Field

[0001] This invention belongs to the fields of flexible electronics, neural engineering and biosensing technology, specifically relating to a flexible PEDOT:PSS hydrogel fiber neural electrode array and its preparation method and application. Background Technology

[0002] Implantable neural interface technology is a transformative tool in brain science research, providing a sub-millisecond window for analyzing the neural activity of individual neurons. Compared to traditional silicon and metal-based Michigan electrodes and Utah arrays, implantable neural electrodes with one-dimensional (1D) fiber structures offer superior flexibility and micrometer-scale diameters, allowing for implantation into deeper brain regions (compared to 2D electrode devices) and maintaining stable performance under repeated mechanical strain. Furthermore, due to their relatively simple manufacturing process, fiber-based flexible neural electrodes allow for the integration of optical and electrical stimulation with electrophysiological and biochemical information recording, resulting in significant flexibility and application prospects. However, the efficacy of neural interfaces hinges on the compatibility between the electrode device and the local brain environment, including characteristic dimensions, mechanical properties, topology, and biochemical characteristics. Mismatches in these characteristics can exacerbate the heterogeneity between neural electrodes and the biological matrix, leading to inflammation, glial proliferation, and even neuronal death. Currently, fiber electrodes based on metal-loaded polymers or carbon materials generally struggle to achieve both the mechanical modulus required for brain tissue compatibility and biocompatibility (metal corrosion releases toxic ions), making it difficult to meet the requirements for long-term, stable, and reliable in vivo use.

[0003] In recent years, hydrogel neuroelectronics has attracted increasing attention due to its high similarity and affinity to biological tissues. Its beneficial biological properties include high water content, tunable mechanical modulus, ion-rich environment, and all-organic characteristics. However, current hydrogel neural electrodes are still limited by finite microfabrication technology and poor charge transport efficiency, which restricts the miniaturization of electrode devices and the rapid detection of high-frequency action potentials in individual neurons. Furthermore, the porous hydrogel molecular framework lacks strong molecular bonds and crystal structure, making it susceptible to enzymatic degradation and structural collapse in physiological environments, leading to electrode device failure. How to transform the hydrogel concept into a device that both matches the geometry of neurons and maintains stability and durability remains an unresolved engineering challenge.

[0004] In summary, developing a micro-nano-sized hydrogel neural electrode array with excellent electrical activity and physiological stability for single-neuron resolution and long-term stable EEG signal monitoring has significant research value in the fields of sensors and brain science. Summary of the Invention

[0005] The main objective of this invention is to provide a flexible PEDOT:PSS hydrogel fiber neural electrode array, its preparation method, and its application, in order to overcome the shortcomings of the prior art.

[0006] To achieve the aforementioned objectives, the technical solution adopted by this invention includes: This invention provides a method for fabricating a flexible PEDOT:PSS hydrogel fiber neural electrode array, comprising: PEDOT:PSS hydrogel conductive fibers, used as electrodes, were prepared using wet spinning technology. Furthermore, the PEDOT:PSS hydrogel conductive fibers were insulated with uracil-grafted polyvinyl alcohol and assembled to obtain a flexible PEDOT:PSS hydrogel fiber neural electrode array.

[0007] The present invention also provides a flexible PEDOT:PSS hydrogel fiber neural electrode array prepared by the aforementioned preparation method.

[0008] This invention also provides the application of the aforementioned flexible PEDOT:PSS hydrogel fiber neural electrode array in neuron resolution, EEG signal monitoring, or flexible brain-computer interfaces.

[0009] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) Compared with currently commercially available metal microfilaments, PI film neural electrodes and carbon fiber electrodes, the hydrogel fiber neural electrode array in this invention has tissue-level bending stiffness matching neurons, submicron-level adjustable geometry, ion-rich water-containing characteristics and open three-dimensional topology. (2) The present invention can realize ultra-fine size to support customized high-density, high-throughput device assembly, while meeting the requirements of efficient monitoring of single neuron signals, effectively reducing the surgical window and invasive damage; the tissue-matched bending stiffness can reduce electrode shear damage caused by environmental micro-movement; finally, the ion-rich environment after full water absorption and swelling is conducive to the formation of a symbiotic interface between the hydrogel electrode and brain tissue, which greatly reduces immune rejection and prolongs the in vivo lifespan. (3) The hydrogel fiber neural electrode array in this invention can achieve long-term in vivo stable tracking of spike signals with single neuron resolution, providing a feasible information interaction tool for a new generation of biocompatible brain-computer interface devices. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a schematic diagram of a wet spinning apparatus used in a typical embodiment of the present invention; Figure 2 This is a geometric morphology diagram of PEDOT:PSS hydrogel conductive fibers prepared in a typical embodiment of the present invention. Figure 3 This is a graph showing the mass and diameter changes during the swelling equilibrium process of PEDOT:PSS hydrogel fibers in a typical embodiment of the present invention. Figure 4 This is a diagram showing the mechanical properties of PEDOT:PSS hydrogel fibers under dehydration and swelling equilibrium conditions in a typical embodiment of the present invention. Figure 5 This is a graph showing the electrochemical performance of PEDOT:PSS hydrogel fibers in PBS solution in a typical embodiment of the present invention. Figures 6a-6b These are the NMR and IR spectra of the uracil-grafted polyvinyl alcohol insulating encapsulation layer in a typical embodiment of the present invention; Figure 7 This is a schematic diagram of the assembly process of a hydrogel neural electrode array in a typical embodiment of the present invention; Figure 8 This is a cross-sectional topography diagram of a 16-channel hydrogel fiber neural electrode array in a typical embodiment of the present invention; Figure 9 This is an impedance data graph of a single-channel hydrogel neural electrode placed in PBS solution for an extended period of time in a typical embodiment of the present invention. Figure 10 This is a graph of neural signal monitoring data of a hydrogel neural electrode array in a typical embodiment of the present invention; Figure 11 This is a long-term performance diagram of a hydrogel neural electrode array in a typical embodiment of the present invention. Figure 12 This is a schematic diagram illustrating the fabrication principle of a hydrogel neural electrode array in a typical embodiment of the present invention. Detailed Implementation

[0012] In view of the deficiencies of the prior art, the inventors of this case, through long-term research and extensive practice, have proposed the technical solution of this invention. The technical solution of this invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0013] Specifically, as one aspect of the technical solution of this invention, the method for preparing a flexible PEDOT:PSS hydrogel fiber neural electrode array includes: PEDOT:PSS hydrogel conductive fibers, used as electrodes, were prepared using wet spinning technology. Furthermore, the PEDOT:PSS hydrogel conductive fibers were insulated with uracil-grafted polyvinyl alcohol and assembled to obtain a flexible PEDOT:PSS hydrogel fiber neural electrode array.

[0014] In some preferred embodiments, the method for fabricating the flexible PEDOT:PSS hydrogel fiber neural electrode array includes: (1) Prepare materials with a diameter of 1-20 μm, a Young's modulus of 10-50 kPa, and a bending stiffness of 1-10 kPa. -11 nN•m 2 PEDOT:PSS hydrogel conductive fibers with a balanced swelling ratio of 40-60%.

[0015] (2) Preparation of uracil-grafted polyvinyl alcohol polymer.

[0016] (3) Use the polymer material prepared in step (2) to impregnate the conductive fiber prepared in step (1) with insulation, and connect and encapsulate it with the back-end module interface.

[0017] In some preferred embodiments, the diameter of the PEDOT:PSS hydrogel conductive fiber is 1~20 μm.

[0018] In some preferred embodiments, the PEDOT:PSS hydrogel conductive fiber has a Young's modulus of 10~50 kPa and a flexural stiffness of 1~10 kPa. -11 nN·m 2 .

[0019] In some preferred embodiments, the equilibrium swelling ratio of the PEDOT:PSS hydrogel conductive fiber is 40-60%.

[0020] In some preferred embodiments, the preparation method specifically includes: using wet spinning technology, using PEDOT:PSS solution as spinning solution, spinning using a double coagulation bath wet spinning system, and then performing an annealing treatment to obtain PEDOT:PSS hydrogel conductive fiber.

[0021] Furthermore, the content of PEDOT:PSS in the spinning solution is 0.5~2.0 wt%.

[0022] Furthermore, the solvent in the spinning solution includes, but is not limited to, dimethyl sulfoxide.

[0023] Furthermore, the dual coagulation bath wet spinning system includes a primary coagulation bath device and a secondary coagulation bath device.

[0024] Furthermore, the primary coagulation bath used in the dual coagulation bath wet spinning system includes, but is not limited to, a phosphoric acid isopropanol solution.

[0025] Furthermore, the temperature of the primary coagulation bath is 15~35℃.

[0026] Furthermore, the concentration of the primary coagulation bath is 0.05~0.1 mol / L.

[0027] Furthermore, the temperature of the secondary coagulation bath is 85~100℃.

[0028] Furthermore, the volume concentration of the secondary coagulation bath is 85 vol.

[0029] Furthermore, the secondary coagulation bath used in the dual coagulation bath wet spinning system includes, but is not limited to, an aqueous solution of N'N dimethylformamide.

[0030] Furthermore, when using wet spinning technology, the spinning speed of the fiber in the primary coagulation bath is 1.0~10 μL·min. -1 The fiber draw ratio in the secondary coagulation bath is 0.5~1.5.

[0031] Furthermore, the temperature of the first annealing treatment is 140~160℃, and the time is 15~45min.

[0032] In some more specific implementations, a diameter of 1–20 μm, a Young's modulus of 10–50 kPa, and a bending stiffness of 1–10 are prepared. -11 nN•m 2 The method for producing PEDOT:PSS hydrogel conductive fibers with a balanced swelling ratio of 40-60% includes the following steps: (1) Prepare a wet spinning solution based on PEDOT:PSS conductive polymer, including 0.5~2.0wt% PEDOT:PSS content and 5wt% dimethyl sulfoxide content.

[0033] (2) Fiber production is further carried out using a double coagulation bath wet spinning device, wherein the primary coagulation bath is an isopropanol solution of phosphoric acid (25℃, 0.05~0.1 M), and the secondary coagulation bath is... N'N Dimethylformamide aqueous solution (90℃, 85 vol%), with a spinneret pump rate of 1.0~10 μL·min. -1 The nascent fibers were drawn up to 0.5-1.5 in the secondary coagulation bath.

[0034] (3) Finally, the fibers prepared by the secondary coagulation bath are subjected to tension-induced annealing treatment at a temperature of 140~160℃ for 30 min.

[0035] In some preferred embodiments, the preparation method specifically includes: 2-Amino-4-hydroxy-6-methylpyrimidine and 1,6-diisocyanate hexane were mixed and reacted at 100 °C for 16 h to obtain the intermediate product; Furthermore, the intermediate product is mixed with polyvinyl alcohol and N-methyl-2-pyrrolidone, and stirred and reacted in a protective atmosphere at a temperature of 75°C for 1-3 hours to obtain uracil-grafted polyvinyl alcohol.

[0036] Furthermore, the molar ratio of 2-amino-4-hydroxy-6-methylpyrimidine to 1,6-diisocyanate hexane is 0.7:4.75.

[0037] Furthermore, the molar ratio of the intermediate product to polyvinyl alcohol is 0.75~1.25:5.

[0038] In some more specific embodiments, the preparation of a uracil-grafted polyvinyl alcohol polymer (PVA-UPy) for PEDOT:PSS hydrogel fiber insulating encapsulation includes the following steps: (1) Dissolve 0.7 mol of 2-amino-4-hydroxy-6-methylpyrimidine in 4.75 mol of 1,6-diisocyanate hexane and heat at 100 °C for 16 h. The resulting mixture is centrifuged, washed and dried with pentane solvent. (2) Dissolve the product (2.27 mol) obtained in step (1) and polyvinyl alcohol (11.3 mol) in N-methyl-2-pyrrolidone (NMP), stir at 75°C for 1 h under a nitrogen atmosphere, and place the reaction product in an oven at 70°C for 24 h to evaporate the NMP solvent to obtain uracil-grafted polyvinyl alcohol.

[0039] In some preferred embodiments, the preparation method specifically includes: A uracil-grafted polyvinyl alcohol is dissolved in water to form an encapsulation solution; The PEDOT:PSS hydrogel conductive fibers are impregnated with the encapsulation solution for insulation treatment, followed by drying to obtain an insulated fiber electrode. The insulating fiber electrodes are arrayed using a custom mold, the insulating layer at the connection between the electrodes and the PCB board gold electrodes is etched using a trace amount of ionized water, and the electrodes are connected using silver paste. The PCB board and mold connected with fiber electrodes were subjected to a second annealing treatment at 150°C for 30 min, and the gold-silver paste-fiber electrode connection of the PCB board was completely encapsulated with silicone rubber coating. Furthermore, a flexible PEDOT:PSS hydrogel fiber neural electrode array was fabricated by using liquid nitrogen to brittle the fiber electrodes and exposing the tail electrode points, removing the mold, and then fabricating the array.

[0040] Furthermore, the concentration of the encapsulation solution is 10~20 wt%.

[0041] Furthermore, the dip-coating insulation treatment uses a dip-coating speed of 1~5 mm·s. -1 .

[0042] Furthermore, the drying process is carried out at a temperature of 75°C.

[0043] In some more specific implementations, assembling a PEDOT:PSS hydrogel fiber neural electrode array includes the following steps: (1) Core-shell structured PVA-UPy@PEDOT:PSS hydrogel fibers were prepared by coating method. The concentration of the coating solution was 10~20 wt%, and the coating speed was 1~5 mm·s. -1 The drying temperature is 75℃; (2) Further take a 5cm long coated hydrogel fiber electrode, use a custom mold to arrange the fiber electrode in an array, use a small amount of ionized water under a microscope to melt the insulating layer at the connection between the fiber electrode and the PCB board gold electrode, and use 30wt% silver paste to connect the electrodes. (3) Further place the PCB board and mold connected with fiber electrodes in a 150℃ oven for secondary annealing for 30 min; (4) Further trim the fiber length to 2~8mm, use liquid nitrogen to brittle the fiber electrode and expose the tail electrode point, and remove the mold.

[0044] (5) Finally, the bulk fibers are bundled and dried using PEG solution, and the PCB board is thoroughly encapsulated using silicone rubber to obtain the PEDOT:PSS hydrogel fiber electrode array device.

[0045] A schematic diagram illustrating the fabrication principle of the hydrogel neural electrode array in a typical embodiment of the present invention is shown below. Figure 12 As shown.

[0046] Another aspect of the present invention provides a flexible PEDOT:PSS hydrogel fiber neural electrode array prepared by the aforementioned preparation method.

[0047] Another aspect of the present invention provides the application of the aforementioned flexible PEDOT:PSS hydrogel fiber neural electrode array in neuron resolution, EEG signal monitoring, or flexible brain-computer interfaces.

[0048] The technical solution of the present invention will be further described in detail below with reference to several preferred embodiments and accompanying drawings. This embodiment is implemented on the premise of the technical solution of the invention, and provides detailed implementation methods and specific operation processes. However, the protection scope of the present invention is not limited to the following embodiments.

[0049] Unless otherwise specified, the experimental materials used in the examples below can be purchased from conventional biochemical reagent companies.

[0050] Example 1 To achieve single-neuron resolution cell signal recording, the examples demonstrate the detailed method of preparing 1-20 micrometer diameter tunable PEDOT:PSS hydrogel fiber samples and a 16-channel neural array by adjusting the wet spinning process in this invention: 0.05 g of PEDOT:PSS was fully dissolved and dispersed in 5 ml of DMSO solvent with a solid content of 5 wt% to prepare the spinning solution. The solution was filtered using a 0.45 μm filter and defoamed under negative pressure (0.1 Pa). A self-made wet spinning apparatus (such as...) was used. Figure 1 Fiber preparation was performed using a spinneret with an inner diameter of 0.06 mm (34G) and a pump speed of 1.0 μL·min. -1 The primary coagulation bath is a 0.05 M isopropanol solution containing phosphoric acid. The nascent fibers enter the bath after being drawn by the spinning rollers. N'N A two-stage coagulation bath (90℃) was used with dimethylformamide solvent, and the front and rear roller speed ratio was set to 1:2 to achieve one-fold drawing. The dried and collected fibers were fixed and placed on a hot plate for annealing at 140℃ for 30 min. The morphology of the fibers prepared under these parameters is as follows. Figure 2As shown, the fiber diameter can reach 0.97 μm. Furthermore, by adjusting the concentration of the PEDOT:PSS spinning solution, the spinneret diameter, and the draw ratio, the diameter of the PEDOT:PSS hydrogel fibers can be controlled within the range of 1-20 micrometers. PEDOT:PSS hydrogel fibers with a diameter of approximately 5 μm were immersed in PBS solution to simulate a physiological environment. After 72 hours of full swelling, the equilibrium swelling rates for the mass and size of the hydrogel fibers were 46% and 65%, respectively (e.g., ...). Figure 3 (As shown). Further stress-strain tests were performed on the sample, and Young's modulus was calculated (e.g., ...). Figure 4 As shown in the figure, the Young's moduli of the hydrogel fiber in its dehydration and swelling equilibrium states are 575 MPa and 67 kPa, respectively. This variable rigidity is beneficial for electrode implantation and long-term use. Finally, the charge storage and charge injection capabilities of the material were evaluated using cyclic voltammetry and chronovoltammetry tests on the fiber using an electrochemical workstation. The results are as follows. Figure 5 As shown, their values ​​are 56.73 mC·cm⁻¹. -2 6.1 mC·cm - ² These excellent electrochemical properties lay the foundation for the material's application in high-frequency electroencephalogram (EEG) signal detection and electrostimulation.

[0051] The specific steps for preparing PVA-UPy polymer include: dissolving 0.7 mol of 2-amino-4-hydroxy-6-methylpyrimidine in 4.75 mol of 1,6-diisocyanate hexane and heating at 100 °C for 16 h; centrifuging, washing, and drying the resulting mixture with pentane solvent; then dissolving the obtained product (2.27 mol) and polyvinyl alcohol (11.3 mol) in N-methyl-2-pyrrolidone (NMP), stirring at 75 °C for 1 h under a nitrogen atmosphere, and placing the reaction product in an oven at 70 °C for 24 h to evaporate the NMP solvent, thereby obtaining uracil-grafted polyvinyl alcohol (PVA-UPy). Figures 6a-6b The NMR and IR spectra of the product PVA-UPy are shown. Figure 7 A schematic diagram of the assembly of the hydrogel fiber electrode array is shown. First, a 15 wt% PVA-UPy polymer aqueous solution was prepared, and a vertical dip-coating method was used with a coating speed of 2 mm / s. -1 Hydrogel fibers were arrayed on a self-made mold, with the ends of the fibers connected to metal electrode plates via conductive silver paste after the insulating layer was dissolved with deionized water. Dry curing and annealing were then performed to improve the water stability of the insulating layer. The fibers were cut to a length of 5 mm, and the tips were further brittled using liquid nitrogen to expose the electrode cross-section. An electrode release device was then used to bundle the scattered electrode filaments into a single fiber in a PEG solution. Figure 8The diagram shows the interface of the 16-channel bundled fiber electrodes. Finally, the PCB board was fully encapsulated with silicone rubber to obtain the PEDOT:PSS hydrogel fiber electrode array device. Figure 9 Impedance data for a single-channel PEDOT:PSS hydrogel fiber electrode were stored in PBS solution for 60 days, demonstrating its stable electrical performance. Figure 10 The analysis of 16 channels of EEG signals from the implanted electrode device in the M2 brain region of mice, as well as the Spike signal of single neuron firing obtained from the processing, demonstrates the good signal acquisition capability of the hydrogel fiber electrode array. Figure 11 The signal changes of representative channels over 6 months demonstrate the stable and reliable in vivo performance of the hydrogel fiber electrode array.

[0052] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0053] It should be understood that the technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made to the technical solutions of the present invention without departing from the spirit and scope of the claims are within the scope of protection of the present invention.

Claims

1. A method for preparing a flexible PEDOT:PSS hydrogel fiber neural electrode array, characterized in that, include: PEDOT:PSS hydrogel conductive fibers, used as electrodes, were prepared using wet spinning technology. Furthermore, the PEDOT:PSS hydrogel conductive fibers were insulated with uracil-grafted polyvinyl alcohol and assembled to obtain a flexible PEDOT:PSS hydrogel fiber neural electrode array.

2. The preparation method according to claim 1, characterized in that: The diameter of the PEDOT:PSS hydrogel conductive fiber is 1~20μm; And / or, the PEDOT:PSS hydrogel conductive fiber has a Young's modulus of 10~50 kPa and a flexural stiffness of 1~10 kPa. -11 nN·m 2 ; And / or, the equilibrium swelling ratio of the PEDOT:PSS hydrogel conductive fiber is 40~60%.

3. The preparation method according to claim 1, characterized in that, Specifically, it includes: PEDOT:PSS hydrogel conductive fibers were prepared by using wet spinning technology, with PEDOT:PSS solution as the spinning solution and a double coagulation bath wet spinning system. After a first annealing treatment, PEDOT:PSS hydrogel conductive fibers were obtained.

4. The preparation method according to claim 3, characterized in that: The content of PEDOT:PSS in the spinning solution is 0.5~2.0 wt%; and / or, the solvent in the spinning solution includes dimethyl sulfoxide; And / or, the dual coagulation bath wet spinning system includes a primary coagulation bath device and a secondary coagulation bath device; And / or, the primary coagulation bath of the dual coagulation bath wet spinning system comprises an isopropanol solution of phosphoric acid; preferably, the temperature of the primary coagulation bath is 15~35℃; preferably, the concentration of the primary coagulation bath is 0.05~0.1mol / L; preferably, the temperature of the secondary coagulation bath is 85~100℃; preferably, the volume concentration of the secondary coagulation bath is 85vol% And / or, the secondary coagulation bath used in the dual coagulation bath wet spinning system includes an aqueous solution of N,N-dimethylformamide; And / or, when using wet spinning technology, the spinning speed of the fiber in the primary coagulation bath is 1.0~10 μL·min. -1 The fiber draw ratio in the secondary coagulation bath is 0.5~1.5; And / or, the temperature of the first annealing treatment is 140~160℃, and the time is 15~45min.

5. The preparation method according to claim 1, characterized in that, Specifically, it includes: 2-Amino-4-hydroxy-6-methylpyrimidine and 1,6-diisocyanate hexane were mixed and reacted at 100 °C for 16 h to obtain the intermediate product; Furthermore, the intermediate product is mixed with polyvinyl alcohol and N-methyl-2-pyrrolidone, and stirred and reacted in a protective atmosphere at a temperature of 75°C for 1-3 hours to obtain uracil-grafted polyvinyl alcohol.

6. The preparation method according to claim 5, characterized in that: The molar ratio of 2-amino-4-hydroxy-6-methylpyrimidine to 1,6-diisocyanate hexane is 0.7:4.75; And / or, the molar ratio of the intermediate product to polyvinyl alcohol is 0.75 to 1.25:

5.

7. The preparation method according to claim 1, characterized in that, Specifically, it includes: A uracil-grafted polyvinyl alcohol is dissolved in water to form an encapsulation solution; The PEDOT:PSS hydrogel conductive fibers are impregnated with the encapsulation solution for insulation treatment, followed by drying to obtain an insulated fiber electrode. The insulating fiber electrodes are arrayed using a custom mold, the insulating layer at the connection between the electrodes and the PCB board gold electrodes is etched using a trace amount of ionized water, and the electrodes are connected using silver paste. The PCB board and mold connected with fiber electrodes were subjected to a second annealing treatment at 150°C for 30 min, and the gold-silver paste-fiber electrode connection of the PCB board was completely encapsulated with silicone rubber coating. Furthermore, a flexible PEDOT:PSS hydrogel fiber neural electrode array was fabricated by using liquid nitrogen to brittle the fiber electrodes and exposing the tail electrode points, removing the mold, and then fabricating the array.

8. The preparation method according to claim 7, characterized in that: The concentration of the encapsulation solution is 10~20 wt%; And / or, the dip-coating insulation treatment uses a dip-coating speed of 1~5 mm·s. -1 ; And / or, the drying process is carried out at a temperature of 75°C.

9. A flexible PEDOT:PSS hydrogel fiber neural electrode array prepared by any one of claims 1-8.

10. The application of the flexible PEDOT:PSS hydrogel fiber neural electrode array of claim 9 in neuron resolution, EEG signal monitoring, or flexible brain-computer interface.

Images