Coaxial spinning prepared biocompatible flexible carbon-based physiological electrode and application thereof

Abstract

The application relates to the technical field of flexible bioelectronic and biomedical sensors, in particular to a biocompatible flexible carbon-based physiological electrode prepared through coaxial spinning and an application thereof, which comprises a three-layer structure; a conductive core is crosslinked by graphene oxide, carbon nanotubes and the like; a buffer layer contains polyurethane and the like, and is added with shape memory microspheres and antibacterial nano-silver; a biological interface layer contains chitosan and the like, and is grafted with PEG-PE to reduce protein adsorption; the thickness ratio of the three layers is 1:(1.5-2):(0.5-1), and the thickness is 100-300 micrometers; the electrode has the functions of electric conduction, sensing and antibiosis, can load double enzymes for blood glucose monitoring, has strong interlayer combination, and is suitable for various biomedical scenes. Through the innovative three-layer structure and material design, the application has the advantages of high electric conduction, strong flexibility, excellent biocompatibility, can realize multi-parameter monitoring and electric stimulation treatment, has good bending resistance, has good antibacterial and anticoagulation effects, the preparation process is controllable, and has wide application prospects in the fields of wearable devices, implantation medical treatment and the like.

Description

Technical Field

[0001] This invention relates to the field of flexible bioelectronics and biomedical sensor technology, specifically to a biocompatible flexible carbon-based physiological electrode prepared by coaxial spinning and its application. Background Technology

[0002] In the field of biomedical monitoring and treatment, physiological electrodes are core devices for acquiring human electrical signals (such as electrocardiograms, electroencephalograms, and electromyograms) and implementing electrical stimulation therapy. Their performance directly affects diagnostic accuracy and treatment efficacy. Traditional physiological electrodes mostly use metallic materials (such as silver / silver chloride electrodes) or rigid carbon materials, which have drawbacks such as poor biocompatibility and incompatibility of mechanical properties with human tissues. Metallic electrodes are prone to causing skin allergies and inflammatory reactions, and signal attenuation occurs due to ion migration during prolonged use. Although rigid carbon electrodes have a certain degree of conductivity, they lack flexibility and cannot adapt to the dynamic deformation of the skin or organ surface, resulting in unstable signal acquisition and even tissue damage.

[0003] With the development of flexible electronics technology, flexible physiological electrodes have gradually become a research hotspot. Existing flexible electrodes are mainly prepared through processes such as solution coating and imprinting, which suffer from problems such as simple structure and low functional integration. For example, electrodes based on polydimethylsiloxane (PDMS) and carbon nanomaterial composites, while flexible, suffer from unevenly dispersed conductive networks, resulting in low electrode conductivity (<10 S / cm) and large resistance fluctuations during stretching. Single-component fiber electrodes prepared by electrospinning struggle to simultaneously achieve high conductivity, biocompatibility, and mechanical buffering performance, failing to meet the requirements for long-term stable use under complex physiological environments.

[0004] At the level of electrode-biointerface interaction, existing technologies face numerous challenges. Protein adsorption and cell adhesion on the electrode surface can lead to signal interference and inflammatory responses, affecting monitoring accuracy and safety. For implantable electrodes, the lack of effective antibacterial and anti-inflammatory functions increases the risk of infection. Furthermore, traditional electrodes have limited functionality, only capable of acquiring electrical signals, and cannot meet the needs of multi-parameter monitoring (such as blood glucose and hydrogen peroxide concentration) and synergistic electrical stimulation therapy, thus limiting their application in wearable medical devices and implantable medical devices.

[0005] While existing research has attempted to improve electrode performance through material modification and structural optimization, limitations remain. Most studies focus on improving only a single property, such as enhancing biocompatibility through surface coatings or increasing conductivity by adding conductive fillers, lacking a systematic and innovative design encompassing electrode materials, structure, and function. Regarding fabrication processes, current technologies struggle to precisely control the interfacial bonding of multilayer structures and the uniform dispersion of nanoscale functional units, leading to unstable electrode performance and significant batch-to-batch variations. Therefore, there is an urgent need to develop a flexible physiological electrode and its fabrication technology that combines high conductivity, biocompatibility, mechanical adaptability, and multifunctional integration to meet the growing clinical needs and technological upgrade requirements of the biomedical field. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] To address the shortcomings of existing technologies, this invention provides a biocompatible flexible carbon-based physiological electrode prepared by coaxial spinning and its application.

[0008] (II) Technical Solution

[0009] A biocompatible flexible carbon-based physiological electrode prepared by coaxial spinning, the electrode comprising a three-layer structure from the inside out:

[0010] The innermost layer is a conductive core, which is formed by cross-linking graphene oxide, carbon nanotubes, polypyrrole, 1-butyl-3-methylimidazolium hexafluorophosphate, bisphenol A diglycidyl ether, and benzoyl peroxide to form a conductive network; the structural formula of 1-butyl-3-methylimidazolium hexafluorophosphate is:

[0011]

[0012] The structural formula of the bisphenol A diglycidyl ether is:

[0013]

[0014] The structural formula of benzoyl peroxide is:

[0015]

[0016] The middle layer is a buffer layer composed of polyurethane, polycaprolactone, gelatin, glycerol and silver nanoparticles; the outermost layer is a bio-interface layer composed of chitosan, hyaluronic acid, polydopamine, RGD sequence integrin-binding peptide and triacetin ester. The thickness ratio of the three layers is 1:(1.5-2):(0.5-1), and the overall thickness is 100-300μm.

[0017] Preferably, it also includes porphyrin iron complex Fe-TPP uniformly dispersed in the conductive core, with a content of 0.5-2 parts.

[0018] Preferably, the buffer layer also includes shape memory polyurethane microspheres introduced in the buffer layer, with a content of 5-10 parts, a phase transition temperature of 40-45℃, and a particle size of 5-20μm.

[0019] Preferably, the bio-interface layer further includes polyethylene glycol-modified phosphatidylethanolamine (PEG-PE) grafted via click chemistry, with a grafting density of [missing information]. .

[0020] Preferably, a transition layer formed by dopamine self-polymerization is provided between the conductive core and the buffer layer, with a thickness of 50-200 nm, and gold nanoparticles with a diameter of 2-5 nm are uniformly distributed in the transition layer.

[0021] Preferably, the electrode surface is further loaded with glucose oxidase (GOx) and horseradish peroxidase (HRP), with enzyme loadings of respectively... Within the glucose concentration range of 1-20 mmol / L, the current response sensitivity is... .

[0022] Preferably, the method for preparing the biocompatible flexible carbon-based physiological electrode includes the following steps:

[0023] S1: Preparation of conductive core spinning solution

[0024] Graphene oxide was dispersed in N,N-dimethylformamide and sonicated for 2-4 hours. Carbon nanotubes were added and sonicated for 1-2 hours. Then, polypyrrole, ionic liquid, porphyrin iron complex, crosslinking agent and initiator were mixed and stirred at 300-500 rpm for 1-2 hours for degassing treatment.

[0025] S2: Preparation of buffer layer spinning solution

[0026] Polyurethane and polycaprolactone were dissolved in a dichloromethane / acetone mixed solvent, and gelatin, glycerin, nano-silver particles and shape memory polyurethane microspheres were added. The mixture was ultrasonically dispersed for 30-60 min and stirred at 200-400 rpm for 1-2 h.

[0027] S3: Preparation of bio-interface layer spinning solution

[0028] After chitosan is dissolved in acetic acid solution, hyaluronic acid, polydopamine, integrin-binding peptide and PEG-PE are added in sequence. Stir at 150-300 rpm to dissolve and add plasticizer.

[0029] S4: Coaxial spinning forming

[0030] The three-layer spinning solution is extruded through a coaxial nozzle and coagulated in an ethanol / water solution containing 5-10% calcium chloride. The coagulation bath temperature is 10-15℃, and the solution is left to stand for 3-5 minutes. After washing with water, the solution is removed.

[0031] S5: Post-processing

[0032] The electrode was heat-treated at 60-80℃ with a heating rate of 5℃ / min for 1-2 hours, then immersed in an ethanol solution containing 5-20 mg / mL dexamethasone, loaded with drug at 25℃ and 50 rpm for 24-48 hours, and then pre-dried at 40℃ under a vacuum of <10 Pa for 2 hours.

[0033] Preferably, during the S4 coaxial spinning process, a 5-10kV DC electric field is applied to the nozzle to orient the carbon nanotubes along the direction of the electric field, with an orientation degree of 0.85-0.95. At the same time, a 1-2T magnetic field is applied to the surface of the receiving device to make the gold nanoparticles uniformly distributed in the transition layer.

[0034] Preferably, in the S5 post-treatment, the electrode is first soaked in 0.1-0.5% glutaraldehyde in a PBS solution for cross-linking for 1-2 hours, and then sequentially immersed in enzyme solutions of GOx and HRP to load the two enzymes through physical adsorption and covalent binding, with enzyme solution concentrations of 1-5 mg / mL and 0.5-3 mg / mL, respectively.

[0035] Preferably, the application of the biocompatible flexible carbon-based physiological electrode is in wearable continuous blood glucose monitoring systems, implantable neural signal recording devices, muscle electrical stimulation therapy for sports rehabilitation, and chronic wound healing monitoring and electrotherapy.

[0036] (iii) Beneficial technical effects

[0037] Compared with existing technologies, the beneficial effects of this invention are:

[0038] 1. The conductive core incorporates porphyrin iron complexes and oriented carbon nanotubes, enhancing electrode conductivity and providing hydrogen peroxide catalytic response, suitable for biomarker detection. The buffer layer, embedded with shape-memory polyurethane microspheres, imparts excellent stability to the electrode's resistance change rate, while nano-silver particles provide antibacterial protection. The bio-interface layer, through PEG-PE grafting and dual-enzyme loading, significantly reduces protein adsorption, enabling continuous blood glucose monitoring with high sensitivity. .

[0039] 2. Improved stability of electrode signal acquisition; enhanced interlayer bonding strength compared to traditional flexible electrodes, effectively preventing delamination. Furthermore, the dexamethasone loaded on the electrode surface can be continuously released for more than 14 days. Combined with the anticoagulant properties of PEG-PE, this reduces the risk of infection in implantation scenarios while maintaining good cell adhesion.

[0040] 3. Coaxial spinning combined with synergistic regulation of electric and magnetic fields enables precise orientation and uniform dispersion of nanomaterials; click chemistry grafting and dual-enzyme loading techniques ensure stable modification of functional molecules. This process allows for the mass production of electrodes with a batch-to-batch performance variation coefficient of <5%, meeting industrialization requirements.

[0041] 4. This electrode can be widely used in wearable medical devices, implantable monitoring systems, and electrical stimulation therapy. In continuous blood glucose monitoring, the detection range covers 1-20 mmol / L with an error of ≤3%. When used for muscle electrical stimulation rehabilitation, the stimulation intensity can be adjusted in real time according to electromyographic signals, improving treatment efficiency. Attached Figure Description

[0042] Figure 1 This is a flowchart of a method for preparing a biocompatible flexible carbon-based physiological electrode by coaxial spinning, as disclosed in this invention.

[0043] Figure 2 This is a comparison chart of the conductivity and resistance change rate after 500 bends between the embodiment and the comparative example;

[0044] Figure 3 This is a line graph comparing the protein adsorption amounts of the examples and the comparative examples;

[0045] Figure 4 The example is a radar comparison chart produced after standardizing the basic performance parameters of the comparative example. Detailed Implementation

[0046] according to Figures 1 to 4 The specific embodiments of the present invention are as follows:

[0047] I. Preparation of Materials and Instruments

[0048] 1. Experimental Materials

[0049] Conductive core materials: graphene oxide (sheet diameter 2-3μm, Nanjing Xianfeng Nano), single-walled carbon nanotubes (tube diameter 15-25nm, length 8-12μm), polypyrrole (conductivity 60S / cm), 1-butyl-3-methylimidazolium hexafluorophosphate, bisphenol A diglycidyl ether, benzoyl peroxide, porphyrin iron complex (Fe-TPP), N,N-dimethylformamide (DMF, analytical grade).

[0050] Buffer layer raw materials: polyurethane (Shore hardness 85A), polycaprolactone (molecular weight 60,000 Da), gelatin (250 Bloom), glycerin, nano silver particles (particle size 30nm), shape memory polyurethane microspheres (phase change temperature 42℃, particle size 8-15μm), dichloromethane (chromatographic grade), acetone (chromatographic grade).

[0051] Bio-interface layer raw materials: chitosan (degree of deacetylation 92%), hyaluronic acid (molecular weight 2 million Da), polydopamine, RGD sequence integrin-binding peptide, polyethylene glycol-modified phosphatidylethanolamine (PEG-PE, molecular weight 5000 Da), triacetin, 2% acetic acid solution.

[0052] Functional loading ingredients: dexamethasone, glucose oxidase (GOx, ≥100U / mg), horseradish peroxidase (HRP, ≥250U / mg), glutaraldehyde (25% aqueous solution).

[0053] 2. Instruments and Equipment

[0054] Ultrasonic cell disruptor (1200W power), rotary evaporator, custom triaxial coaxial spinning machine (nozzle inner diameter: inner layer 0.3mm, middle layer 0.7mm, outer layer 1.2mm), vacuum drying oven, fluorescence microscope, electrochemical workstation (CHI660E), scanning electron microscope (SEM).

[0055] II. Example 1: Preparation of physiological electrodes using standard processes

[0056] Preparation of conductive core spinning solution

[0057] 35g of graphene oxide was dispersed in 1000mL of DMF and sonicated for 4 hours until homogeneous. 25g of carbon nanotubes were added and sonicated for another 2 hours. Then, 20g of polypyrrole, 8g of 1-butyl-3-methylimidazolium hexafluorophosphate, 3g of Fe-TPP, 4g of bisphenol A diglycidyl ether, and 1.5g of benzoyl peroxide were added sequentially. The mixture was stirred at 300rpm for 2 hours and then vacuum degassed for 30 minutes to obtain the desired viscosity. Spinning solution.

[0058] Preparation of buffer layer spinning solution

[0059] 45g of polyurethane and 25g of polycaprolactone were dissolved in 1200mL of a dichloromethane / acetone (2:1, v / v) mixed solvent. Then, 15g of gelatin, 8g of glycerol, 1g of silver nanoparticles, and 8g of shape memory polyurethane microspheres were added. The mixture was ultrasonically dispersed for 45 minutes and stirred at 200rpm for 1.5 hours to obtain the desired viscosity. Spinning solution.

[0060] Preparation of bio-interface layer spinning solution

[0061] Dissolve 35g of chitosan in 1500mL of 2% acetic acid solution, then add 20g of hyaluronic acid, 8g of polydopamine, 0.3g of RGD peptide, and 3g of PEG-PE sequentially. After stirring to dissolve, add 4g of triacetin and stir at 150rpm for 2 hours to obtain the viscosity. Spinning solution.

[0062] Coaxial spinning

[0063] The three spinning solutions were injected into the nozzle at the following flow rates: 1.2 mL / h for the conductive core, 1.5 mL / h for the buffer layer, and 1.0 mL / h for the bio-interface layer. Spinning was performed under an electric field strength of 12 kV and a receiving distance of 15 cm. The fibers were then placed in a 12°C coagulation bath containing 8% calcium chloride in an ethanol / water (1:1) solution and left for 4 minutes before being removed and washed three times with deionized water.

[0064] Post-processing

[0065] The electrode was heat-treated at 70℃ for 1.5 hours; then immersed in 10 mg / mL dexamethasone ethanol solution and shaken at 25℃ and 50 rpm for 48 hours to load the drug. After vacuum drying, it was first immersed in 0.3% glutaraldehyde PBS solution for crosslinking for 1.5 hours, and then successively immersed in 5 mg / mL GOX and 3 mg / mL HRP solutions for 2 hours each to obtain the finished product.

[0066] III. Example 2: Optimizing Blood Glucose Monitoring Performance

[0067] Preparation of conductive core spinning solution

[0068] 35 g of graphene oxide was dispersed in 1000 mL of DMF and sonicated for 4 hours until homogeneous. 25 g of carbon nanotubes were added and sonicated for another 2 hours. 20 g of polypyrrole, 8 g of 1-butyl-3-methylimidazolium hexafluorophosphate, 1.8 g of Fe-TPP, 4 g of bisphenol A diglycidyl ether, and 1.5 g of benzoyl peroxide were added sequentially. The mixture was stirred at 300 rpm for 2 hours and then degassed under vacuum for 30 minutes to obtain a spinning solution with a viscosity of 800 mPa·s.

[0069] Preparation of buffer layer spinning solution

[0070] Same as in Example 1: 45 g of polyurethane and 25 g of polycaprolactone were dissolved in 1200 mL of a dichloromethane / acetone (2:1, v / v) mixed solvent, and 15 g of gelatin, 8 g of glycerol, 1 g of silver nanoparticles and 8 g of shape memory polyurethane microspheres were added. The mixture was ultrasonically dispersed for 45 minutes and stirred at 200 rpm for 1.5 hours to obtain a spinning solution with a viscosity of 1200 mPa·s.

[0071] Preparation of bio-interface layer spinning solution

[0072] Same as in Example 1: 35 g of chitosan was dissolved in 1500 mL of 2% acetic acid solution, and 20 g of hyaluronic acid, 8 g of polydopamine, 0.3 g of RGD peptide and 3 g of PEG-PE were added in sequence. After stirring and dissolving, 4 g of triacetin was added and stirred at 150 rpm for 2 hours to obtain a spinning solution with a viscosity of 600 mPa·s.

[0073] Coaxial spinning

[0074] The three spinning solutions were injected into the nozzle at different flow rates: 1.2 mL / h for the conductive core, 1.5 mL / h for the buffer layer, and 1.0 mL / h for the bio-interface layer. An 8 kV auxiliary electric field was applied to the nozzle, and the receiving distance was 15 cm. The fibers fell into a 12°C coagulation bath containing 8% calcium chloride in an ethanol / water (1:1) solution. After 4 minutes, the fibers were removed and washed three times with deionized water.

[0075] Post-processing

[0076] The electrode was heat-treated at 70℃ for 1.5 hours; then immersed in 10 mg / mL dexamethasone ethanol solution and shaken at 25℃ and 50 rpm for 48 hours to load the drug. After vacuum drying, it was first immersed in 0.3% glutaraldehyde PBS solution for crosslinking for 1.5 hours, and then successively immersed in 8 mg / mL GOx and 5 mg / mL HRP solution for 2 hours each to obtain the finished product.

[0077] IV. Example 3: Scale-up Production Verification

[0078] Preparation of conductive core spinning solution (10 times the amount of raw material)

[0079] 350 g of graphene oxide was dispersed in 10000 mL of DMF and sonicated for 4 hours until homogeneous. 250 g of carbon nanotubes were added and sonicated for another 2 hours. 200 g of polypyrrole, 80 g of 1-butyl-3-methylimidazolium hexafluorophosphate, 30 g of Fe-TPP, 40 g of bisphenol A diglycidyl ether, and 15 g of benzoyl peroxide were added sequentially. The mixture was stirred at 300 rpm for 2 hours and then degassed under vacuum for 30 minutes to obtain a spinning solution with a viscosity of 800 mPa·s.

[0080] Preparation of buffer layer spinning solution (10 times the amount of raw material)

[0081] 450 g of polyurethane and 250 g of polycaprolactone were dissolved in 12000 mL of a dichloromethane / acetone (2:1, v / v) mixed solvent. 150 g of gelatin, 80 g of glycerol, 10 g of silver nanoparticles, and 80 g of shape memory polyurethane microspheres were added, and the mixture was ultrasonically dispersed for 45 minutes and stirred at 200 rpm for 1.5 hours to obtain a spinning solution with a viscosity of 1200 mPa·s.

[0082] Preparation of bio-interface layer spinning solution (10 times the amount of raw material)

[0083] 350 g of chitosan was dissolved in 15000 mL of 2% acetic acid solution, and then 200 g of hyaluronic acid, 80 g of polydopamine, 3 g of RGD peptide and 30 g of PEG-PE were added in sequence. After stirring and dissolving, 40 g of triacetin was added and stirred at 150 rpm for 2 hours to obtain a spinning solution with a viscosity of 600 mPa·s.

[0084] Coaxial spinning (5 consecutive batches produced)

[0085] Inject 10 times the amount of the three-layer spinning solution into the storage tank of the industrial spinning equipment, and continuously produce 5 batches according to the following parameters:

[0086] Flow rates: Conductive core 1.2 mL / h, buffer layer 1.5 mL / h, bio-interface layer 1.0 mL / h (single nozzle parameters, multiple nozzles operating in parallel)

[0087] Electric field strength: 12 kV

[0088] Reception distance: 15 cm

[0089] Coagulation bath conditions: 12℃ ethanol / water (1:1) solution containing 8% calcium chloride, fiber residence time 4 minutes.

[0090] Washing: Each batch of fibers is washed three times with deionized water before entering the drying process.

[0091] Post-processing (batch processing)

[0092] Each batch of electrodes was subjected to the following treatments: Oven treatment at 70°C for 1.5 hours; immersion in 100 mg / mL dexamethasone ethanol solution (total volume scaled up proportionally) at 25°C and 50 rpm for 48 hours; vacuum drying; crosslinking in 3% glutaraldehyde PBS solution for 1.5 hours; followed by immersion in 50 mg / mL GOx and 30 mg / mL HRP solutions for 2 hours each.

[0093] V. Comparative Example: Traditional Single-Layer Carbon-Based Electrode

[0094] Mix carbon nanotubes (20g) with PDMS (80g), add curing agent and stir evenly; coat onto PET substrate and cure at 60℃ for 2 hours; spray chitosan solution onto surface and then dry.

[0095] The basic performance parameters of the examples and comparative examples are compared in the table below:

[0096] Table 1

[0097]

[0098] The electrode in this embodiment exhibits an electrode conductivity of 120-135 S / cm, excellent bending stability (resistance change rate ≤13%), interlayer strength exceeding 20 N / cm, and protein adsorption <5 μg / cm². In contrast, the comparative embodiment has a conductivity of only 12 S / cm, poor stability, and high protein adsorption, demonstrating that the material and structural design of this invention significantly improves overall performance.

[0099] The blood glucose monitoring performance of the examples and comparative examples is compared in the table below:

[0100] Table 2

[0101]

[0102] Examples 1-2 electrodes, through optimized enzyme loading and carbon nanotube orientation, achieve a wide blood glucose monitoring range of 0.5-20 mmol / L, with a maximum sensitivity of [missing information]. The detection limit is as low as 0.5 mmol / L; the comparative sample had no enzyme loading and no blood glucose response, verifying the effectiveness of the functional design of this invention.

[0103] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A biocompatible flexible carbon-based physiological electrode prepared by coaxial spinning, characterized in that, The electrode comprises a three-layer structure from the inside out: The innermost layer is a conductive core, which is a conductive network formed by cross-linking graphene oxide, carbon nanotubes, polypyrrole, 1-butyl-3-methylimidazolium hexafluorophosphate, bisphenol A diglycidyl ether, and benzoyl peroxide. The middle layer is a buffer layer composed of polyurethane, polycaprolactone, gelatin, glycerol and nano-silver particles; the outermost layer is a bio-interface layer composed of chitosan, hyaluronic acid, polydopamine, RGD sequence integrin-binding peptide and triacetin ester. The thickness ratio of the three layers is 1:(1.5-2):(0.5-1), and the overall thickness is 100-300μm. The conductive core also contains uniformly dispersed porphyrin iron complex Fe-TPP; Shape memory polyurethane microspheres are also introduced into the buffer layer. The phase transition temperature of the microspheres is 40-45℃, and the particle size of the shape memory polyurethane microspheres is 5-20μm. The bio-interface layer also includes polyethylene glycol-modified phosphatidylethanolamine (PEG-PE) grafted via click chemistry, with a grafting density of 0.2-0.5 μmol / cm². The electrode surface is also loaded with glucose oxidase (GOx) and horseradish peroxidase (HRP), with enzyme loadings of 5-10 U / cm² and 3-8 U / cm², respectively. Within a glucose concentration range of 1-20 mmol / L, the current response sensitivity is 0.5-2 μA. mmol - ¹ cm - ².

2. The method for preparing the biocompatible flexible carbon-based physiological electrode according to claim 1, characterized in that, Includes the following steps: S1: Preparation of conductive core spinning solution Graphene oxide was dispersed in N,N-dimethylformamide and sonicated for 2-4 hours. Carbon nanotubes were added and sonicated for 1-2 hours. Then, polypyrrole, 1-butyl-3-methylimidazolium hexafluorophosphate, porphyrin iron complex, bisphenol A diglycidyl ether and benzoyl peroxide were mixed and stirred at 300-500 rpm for 1-2 hours for degassing treatment. S2: Preparation of buffer layer spinning solution Polyurethane and polycaprolactone were dissolved in a dichloromethane / acetone mixed solvent, and gelatin, glycerin, nano-silver particles and shape memory polyurethane microspheres were added. The mixture was ultrasonically dispersed for 30-60 min and stirred at 200-400 rpm for 1-2 h. S3: Preparation of bio-interface layer spinning solution After chitosan is dissolved in acetic acid solution, hyaluronic acid, polydopamine, RGD sequence integrin-binding peptide and PEG-PE are added in sequence. The mixture is stirred at 150-300 rpm to dissolve and then triacetin is added. S4: Coaxial spinning forming The three-layer spinning solution is extruded through a coaxial nozzle and coagulated in an ethanol / water solution containing 5-10% calcium chloride. The coagulation bath temperature is 10-15℃, and the solution is left to stand for 3-5 minutes. After washing with water, the solution is removed. S5: Post-processing The electrode was heat-treated at 60-80℃ with a heating rate of 5℃ / min for 1-2 hours, then immersed in an ethanol solution containing 5-20 mg / mL dexamethasone, and loaded with the drug at 25℃ and 50 rpm for 24-48 hours. Subsequently, it was pre-dried at 40℃ under a vacuum of <10 Pa for 2 hours. After vacuum pre-drying, the electrode was first immersed in a PBS solution containing 0.1-0.5% glutaraldehyde for 1-2 hours for cross-linking, and then sequentially immersed in enzyme solutions of GOx and HRP. The two enzymes were loaded through physical adsorption and covalent binding to obtain the finished product. The enzyme solution concentrations were 1-5 mg / mL and 0.5-3 mg / mL, respectively.

3. The application of a biocompatible flexible carbon-based physiological electrode according to claim 1 or a biocompatible flexible carbon-based physiological electrode prepared by the preparation method according to claim 2 in a wearable continuous blood glucose monitoring system and an implantable neural signal recording device.

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