A double-network hydrogel-based biosensor electrode and a preparation method thereof

Abstract

The application discloses a kind of biological sensor electrode based on double-network hydrogel and preparation method thereof, belong to electrochemical biosensing field.The biological sensor electrode includes electrode base material and its surface redox enzyme carrying double-network hydrogel;Redox enzyme carrying double-network hydrogel is obtained by mixing first network hydrogel precursor liquid containing redox enzyme and second network hydrogel stock solution and being treated by light curing, and the first network hydrogel and the second network hydrogel are interpenetrating network structures, which are obtained by physical crosslinking interpenetration;Wherein: the first network hydrogel precursor liquid is obtained by mixing polyetherimide, CHO-Os, crosslinking agent and redox enzyme and then standing reaction;The second network hydrogel stock solution includes acrylic monomer and photoinitiator.The biological sensor electrode obtained by the application has strong electrochemical working time stability, and can better protect the temperature stability of redox enzyme, and has wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical biosensing materials, and specifically relates to a biosensor electrode based on a dual-network hydrogel and its preparation method. Background Technology

[0002] The field of electrochemical biosensing materials integrates electrochemistry, materials science, and biotechnology to develop highly sensitive, selective, and fast-responding biosensors. These sensors have wide applications in fields such as medical diagnostics, environmental monitoring, food safety, and biopharmaceuticals.

[0003] The long-term stability of sensors is regulated by various factors, including the properties of the hydrogel matrix, electron transport efficiency, preservation of enzyme activity, and the stability of electronic devices. Electron mediators are low-molecular-weight, artificially constructed compounds used for electron transfer. They readily participate in redox reactions of biological components and facilitate rapid electron transfer. For example, in bio-enzyme sensors, electron mediators mediate the transfer of electrons generated during enzymatic reactions from the enzyme's active site to the electrode surface, causing a corresponding current change. However, while small-molecule electron mediators can lower the working potential of the enzyme electrode, improve the electron transfer efficiency between the enzyme and the electrode, and reduce interference from electroactive substances, they are also prone to leakage from the modification layer, leading to decreased stability of the prepared electrochemical enzyme sensor and thus limiting its performance. One solution to this problem is to use polymeric electron mediators, specifically those formed by covalently linking small-molecule electron mediators with polymer chains. Hydrogels are highly hydrophilic three-dimensional network gels that swell rapidly in water and retain a large volume of water without dissolving in this swollen state. The entanglement or cross-linking between hydrogel polymer chains can solve the problem of electron media leakage. However, the swelling process of the hydrogel itself can alter the concentration of electron mediators in the modified layer, thereby changing the response characteristics of the modified electrode and leading to decreased sensor stability. The structural and functional stability of enzymes is also a key factor determining the lifespan of a sensor. As protein-based biocatalysts, enzyme conformation is easily affected by temperature fluctuations and changes in the pH of the external environment; conformational changes directly lead to a decrease in their catalytic activity. Furthermore, the loss of enzyme molecules during long-term detection can also cause signal attenuation. These issues collectively limit the long-term stable application of enzyme electrodes in continuous glucose monitoring systems.

[0004] Therefore, it is of great significance to develop a stable dual-network electronic dielectric hydrogel and biosensor electrode based on electronic dielectric hydrogels with good electron transfer capabilities. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a biosensor electrode based on a dual-network hydrogel and its preparation method. This electrode exhibits good electron transfer capability and current response stability, excellent working stability, and superior enzyme functional stability.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a biosensor electrode based on a dual-network hydrogel, comprising an electrode substrate and a dual-network hydrogel carrying an oxidoreductase on the surface of the electrode substrate; the dual-gel network carrying the oxidoreductase is obtained by mixing a first network hydrogel precursor solution containing the oxidoreductase with a second network hydrogel stock solution and then performing photocuring treatment; the first network hydrogel and the second network hydrogel are interpenetrating network structures, obtained through physical cross-linking; wherein: The first network hydrogel precursor solution was obtained by mixing polyetherimide, CHO-Os (chlorinated (aldehyde pyridine)(bis(2,2'-bipyridine)) osmium chloride (II)), crosslinking agent and oxidoreductase and then allowing it to stand for reaction. The second network hydrogel stock solution includes acrylic monomers and photoinitiators.

[0007] According to the above scheme, in the dual-network hydrogel, the mass ratio of polyetherimide used in the first network and acrylic monomer used in the second network is 0.5~1.5:1, preferably 0.8~1.2:1.

[0008] According to the above scheme, the crosslinking agent in the first network hydrogel precursor solution is one of glutaraldehyde, polyethylene glycol diglycidyl ether and its derivatives.

[0009] According to the above scheme, the mass ratio of crosslinking agent to polyetherimide in the first network hydrogel precursor solution is 0.05~2:1.

[0010] According to the above scheme, the mass ratio of CHO-Os electronic mediator to polyetherimide in the first network hydrogel precursor solution is 2~10:1.

[0011] According to the above scheme, the mass ratio of oxidoreductase to polyetherimide in the first network hydrogel precursor solution is 1~5:1.

[0012] According to the above scheme, the oxidoreductase is glucose oxidase or urate oxidase.

[0013] According to the above scheme, the photoinitiator in the second network hydrogel stock solution is 2959, which is 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone.

[0014] According to the above scheme, in the second network hydrogel stock solution, the mass ratio of photoinitiator to acrylic monomer is 0.002~0.05:1.

[0015] According to the above scheme, the thickness of the dual-network hydrogel is 50~200 μm.

[0016] According to the above scheme, the biosensor electrode further includes a protective layer covering the surface of the dual-network hydrogel. Preferably, the protective layer is made of at least one of Nafion (perfluorosulfonic acid polymer) or PU (polyurethane).

[0017] Secondly, the present invention provides a method for preparing the above-mentioned biosensor electrode based on a dual-network hydrogel, comprising the following steps: 1) Polyetherimide and CHO-Os are dissolved in water to prepare the first network hydrogel stock solution; photoinitiator and acrylic acid are mixed and dissolved in water to prepare the second network hydrogel stock solution; 2) Add oxidoreductase aqueous solution and glutaraldehyde aqueous solution to the first network hydrogel stock solution obtained in step 1), stir evenly and let stand to react to obtain the first network hydrogel precursor solution; 3) Add the second network hydrogel stock solution obtained in step 1) to the first network hydrogel precursor solution obtained in step 2), stir evenly to form a double network hydrogel precursor solution; wherein the mass ratio of polyetherimide to acrylic acid is 0.5~1.5:1; 4) Drop the dual-network hydrogel precursor liquid obtained in step 3) onto the electrode substrate, irradiate with ultraviolet light and then dry to obtain the biosensor electrode based on the dual-network hydrogel.

[0018] According to the above scheme, in step 1), the concentration of polyetherimide in the first network hydrogel stock solution is 1~10 mg / mL.

[0019] According to the above scheme, in step 1), the concentration of acrylic acid in the second network hydrogel stock solution is 1~5 mg / mL.

[0020] According to the above scheme, in step 2), the concentration of the oxidoreductase aqueous solution is 5~50 mg / mL; the concentration of the cross-linking agent solution is 0.5~20 mg / mL.

[0021] According to the above scheme, in step 2), the reaction time after adding the crosslinking agent is 1~10 min; preferably 1~5 min.

[0022] According to the above scheme, in step 4), the volume ratio of the dual-network hydrogel precursor solution to the electrode area is 1 μL : 0.01~0.03 cm². 2 .

[0023] According to the above scheme, in step 4), the irradiation power during ultraviolet irradiation is 100~500 W, preferably 400~500 W.

[0024] According to the above scheme, in step 4), the irradiation time during ultraviolet irradiation is 5~50 s; preferably 10~30 s, more preferably 15~25 s.

[0025] According to the above scheme, in step 4), the electrode substrate is a gold disk electrode or a glassy carbon electrode.

[0026] According to the above scheme, step 4) further includes spraying a protective layer, which covers the surface of the dual-network hydrogel to obtain a biosensor electrode based on the dual-network hydrogel.

[0027] Preferably, the protective layer is at least one of Nafion or PU.

[0028] More preferably, the Nafion is obtained by spraying an isopropanol solution of Nafion, wherein the concentration of the isopropanol solution of Nafion is 1~10 mg / mL; preferably 1~5 mg / mL.

[0029] More preferably, the PU is obtained by spraying a tetrahydrofuran solution of PU, wherein the concentration of the tetrahydrofuran solution of PU is 1~10 mg / mL, preferably 1~5 mg / mL.

[0030] Thirdly, the present invention provides an application of the above-mentioned biosensor electrode based on dual-network hydrogel as a working electrode in the field of biosensors.

[0031] According to the above scheme, a biosensor electrode based on a dual-network hydrogel is used as the working electrode, a platinum sheet electrode is used as the counter electrode, and Ag / AgCl is used as the reference electrode to assemble the biosensor.

[0032] The aforementioned biosensors can be used in wearable devices. For example, adding glucose oxidase during the dual-network hydrogel process can determine the concentration of glucose; adding uric acid oxidase during the dual-network hydrogel process can determine the concentration of uric acid; and cross-linking and immobilizing them on microneedle electrodes can create wearable microneedle arrays to detect markers in the interstitial fluid of the skin.

[0033] This invention provides a biosensor electrode based on a dual-network hydrogel. A dual-network PEI-Os / PAA is constructed using polyetherimide / CHO-Os and acrylic acid, and an oxidoreductase is incorporated. This electrode exhibits excellent electron transport capability and anti-swelling properties, strong operational stability, and superior enzyme activity retention. Wherein: Polyacrylic acid hydrogel serves as the rigid main network, while polyetherimide hydrogel acts as the flexible secondary network. The two intertwine to form a dual-network hydrogel, which effectively improves the overall mechanical strength and deformation resistance of the hydrogel structure, reduces swelling deformation and structural relaxation in physiological environments, and effectively reduces the risk of oxidoreductase leakage. At the same time, while maintaining the electron transfer capability of the electron medium, it significantly reduces the decrease in electron transfer efficiency caused by swelling of the electron medium hydrogel, thereby improving the working stability of the electrochemical sensor.

[0034] The first network constructed from polyetherimide / CHO-Os not only provides excellent electron transport capabilities through covalent electron mediators, but also enhances enzyme structural stability by interacting with amino acid residues on the surface of oxidoreductases through its polyamine structure, including weak interactions such as hydrogen bonds. This ensures efficient electron transport while maintaining high enzyme structural stability. Meanwhile, the second network constructed from acrylic acid features abundant carboxyl groups (-COOH / -COO) on its molecular chain. - ); among which the negatively charged carboxylate ion (-COO) - The carboxyl group can form stable electrostatic interactions with the positively charged amino acid residues on the surface of oxidoreductase molecules. In addition, the carboxyl group can form a dense hydrogen bond network with the hydroxyl (-OH), amino (-NH2), and amide (-CONH2) groups on the surface of oxidoreductase. These electrostatic interactions and hydrogen bond networks can effectively "anchor" oxidoreductase, reduce the movement of enzyme molecules inside the hydrogel and the changes in conformation, significantly reduce the risk of protein unfolding caused by temperature changes or pH fluctuations, and significantly improve the functional stability of the enzyme.

[0035] The beneficial effects of this invention are as follows: 1. This invention provides a biosensor electrode based on a dual-network hydrogel, which has good electron transfer capability and current response stability, excellent electrode working stability, and excellent enzyme functional stability, effectively maintaining oxidoreductase activity, improving structural stability and enhancing environmental adaptability.

[0036] 2. This invention provides a method for preparing the above-mentioned biosensor electrode, which is obtained by mixing a first network hydrogel precursor solution containing oxidoreductase with a second network hydrogel stock solution and then dropping the mixture onto an electrode substrate, followed by photocatalytic in-situ polymerization. The preparation method is simple, the conditions are mild, and it has prospects for industrial application. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the synthesis route of the dual-network hydrogel in Example 1; Figure 2 This refers to the hydrogel thickness of the biosensor electrode based on the dual-network hydrogel obtained in Example 1; Figure 3The cyclic voltammetric curves of the biosensor electrode based on dual-network hydrogel obtained in Example 1 and the biosensor electrode based on single-network hydrogel in Comparative Example 1 are shown in 0.2 M potassium chloride solution (containing 4 mM glucose). Figure 4 The time stability of the biosensor electrode based on dual-network hydrogel obtained in Example 1 and the biosensor electrode based on single-network hydrogel in Comparative Example 1 in 0.2 M potassium chloride solution (containing 4 mM glucose); Figure 5 The cyclic voltammetric curves of the biosensor electrode based on the dual-network hydrogel obtained in Example 1 in 0.2 M potassium chloride solution (containing 0 and 8 mM glucose); Figure 6 This is a comparison of the thermal stability of the biosensor electrode based on dual-network hydrogel obtained in Example 1 and the biosensor electrode based on single-network hydrogel obtained in Comparative Example 1 after a 65 °C water bath. Figure 7 The comparison shows the cyclic voltammetric characteristics of the biosensor electrodes based on dual-network hydrogels obtained in Example 1 and Comparative Example 2 in 0.2 M potassium chloride solution (containing 4 mM glucose). Figure 8 This is a comparison of the time stability of the biosensor electrodes based on dual-network hydrogels obtained in Example 1 and Comparative Example 2 in 0.2 M potassium chloride solution (containing 4 mM glucose); Figure 9 This is a comparison of the time stability of the biosensor electrode based on the polyetherimide-CHO-Os / polyacrylic acid dual network obtained in Example 1 and the electronic dielectric hydrogel based on the polyvinyl imidazole-CHO-Os / polyethylene glycol diacrylate dual network obtained in Comparative Example 3. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0039] Example 1 A method for fabricating a biosensor based on a dual-network hydrogel, see [link to documentation]. Figure 1 It includes the following steps: 1) Weigh 10 mg of polyetherimide and 40 mg of CHO-Os and dissolve them in 4 mL of deionized water. Stir until completely dissolved to obtain the first network hydrogel stock solution, wherein the concentration of polyetherimide is 2.5 mg / mL and the concentration of CHO-Os is 10 mg / mL. 2) Weigh 10 mg of photoinitiator 2959 and dissolve it in 1 g of acrylic acid, then sonicate until completely dissolved. Next, weigh 50 mg of acrylic acid containing photoinitiator 2959 and dissolve it in 20 mL of deionized water, stirring until completely dissolved to prepare the second network hydrogel stock solution, wherein the total concentration of acrylic acid and photoinitiator is 2.5 mg / mL; 3) Take 10 μL of the first network hydrogel monomer obtained in step 1), add 2.5 μL of 30 mg / mL glucose oxidase aqueous solution and 1.25 μL of 20 mg / mL glutaraldehyde aqueous solution, stir evenly and let stand for 2 min to obtain the first network hydrogel precursor solution.

[0040] 4) Add 10 μL of the second network hydrogel stock solution obtained in step 2) to the first network hydrogel precursor solution obtained in step 3) and stir evenly to form a dual network hydrogel precursor solution, wherein the mass ratio of polyetherimide, the raw material of the first network hydrogel, to acrylic acid, the raw material of the second network hydrogel, is approximately 1:1.

[0041] 5) Take 1.5 μL of the dual-network conductive hydrogel precursor obtained in step 4) and drop it onto a 2 mm diameter circular gold electrode. Irradiate it under a 500 W UV lamp for 20 s, then allow it to dry naturally. Figure 2 The thickness of the hydrogel obtained is shown to be 102 μm.

[0042] 6) Spray the electrode obtained in step 5) sequentially with 5 mg / mL Nafion isopropanol solution and 5 mg / mL PU tetrahydrofuran solution, and allow it to dry naturally to obtain the biosensor electrode.

[0043] Comparative Example 1 This comparative example, Example 1, uses the same materials and evaluation methods as the examples, except that the resulting product is a single-network hydrogel, and includes the following steps: 1) Weigh 10 mg of polyetherimide and 40 mg of CHO-Os and dissolve them in 4 mL of deionized water. Stir until completely dissolved to prepare the first network hydrogel stock solution. 2) Take 10 μL of the first network hydrogel stock solution obtained in step 1) and add 2.5 μL of 30 mg / mL glucose oxidase and 1.25 μL of 20 mg / mL glutaraldehyde aqueous solution. After stirring evenly, let it stand for 2 min to obtain the hydrogel precursor solution.

[0044] 3) Take 1.5 μL of the hydrogel precursor liquid obtained in step 2) and drop it onto a 2 mm diameter circular gold electrode, and let it dry naturally.

[0045] Using the biosensor electrodes obtained in Example 1 and Comparative Example 1 as working electrodes, a platinum sheet electrode as a counter electrode, and Ag / AgCl as a reference electrode, respectively, the electrochemical performance was evaluated as follows: Cyclic voltammetry curves of the biosensor electrodes obtained in Example 1 and Comparative Example 1 in a 0.2 M potassium chloride solution containing 4 mM glucose were tested using an electrochemical analyzer; the results are as follows: Figure 3 As shown.

[0046] Measurements were taken every 24 hours, and after each test, the sample was immersed in a 0.2 M potassium chloride solution to test its time stability; the results are as follows. Figure 4 As shown in the figure, the dual-network hydrogel biosensor obtained in Example 1 exhibits a more stable current response in a 0.2 M potassium chloride solution containing 4 mM glucose. After 3 days of testing, the current response signal showed virtually no attenuation, while Comparative Example 1 showed an attenuation of 52%, almost half. After another 7 days of testing, the measured current response signal of Example 1 only attenuated by 12%, while Comparative Example 1 attenuated by 59%. This is because the dual-network hydrogel forms a denser hydrogel network, reducing enzyme leakage. The electronic conductivity of the dual-network hydrogel also decreases less, resulting in better current response stability and excellent electrode stability.

[0047] Cyclic voltammetry was performed on a 0.2 M potassium chloride solution containing 0.8 mM glucose, using a polyetherimide-CHO-Os / polyacrylic acid dual-network electronic dielectric hydrogel as the working electrode, a platinum sheet electrode as the counter electrode, and Ag / AgCl as the reference electrode. The results are as follows: Figure 5 As shown, the current is 0.4 μA when the glucose concentration is 0 mM and 1.2 μA when the glucose concentration is 8 mM. When glucose enters the active site of glucose oxidase and is oxidized, the electron-medium hydrogel can acquire the electrons generated during the oxidation process and conduct them to the electrode to generate a change in current, thereby detecting the glucose concentration.

[0048] The enzyme activity of the biosensor electrodes obtained in Example 1 and Comparative Example 1 was evaluated, specifically as follows: In Example 1, insufficient hydrogel on the electrode prevented the instrument from detecting enzyme activity. To verify the protective effect of the dual-network electronic medium hydrogel on enzyme activity, the amount of hydrogel layer was increased, resulting in a larger hydrogel membrane for enzyme activity determination. Following steps 1-4 of Example 1, a dual-network hydrogel precursor solution was obtained. 10 μL of this solution was dropped onto a glass plate that had been impacted with Plasma, and the membrane was irradiated with a 500 W UV lamp for 20 s to obtain the dual-network hydrogel membrane. Similarly, following steps 1 and 3 of Example 1, a single-network hydrogel precursor solution was obtained. 10 μL of this solution was dropped onto a glass plate that had been impacted with Plasma, and the membrane was allowed to dry naturally to obtain the single-network hydrogel membrane.

[0049] Enzyme activity evaluation methods: The two types of hydrogel membranes were incubated at 65 °C for 0, 1, 2, and 3 hours, and the enzyme activity was tested at 500 nm using a UV spectrophotometer. The stability test results are as follows. Figure 6 As shown in the figure. In Example 1, after 3 hours of incubation with the PEI / PAA group immobilized by the dual-network hydrogel, the enzyme activity remained at 69%, significantly better than the 10.9% in the PEI group of Comparative Example 1. This indicates that the dual-network hydrogel obtained by using polyetherimide and acrylic acid in this invention has excellent enzyme functional stability and better enzyme protection.

[0050] Comparative Example 2 This comparative example refers to Example 1. The materials, steps and evaluation methods used are the same as in Example 1. The difference is that in step 4), the mass ratio of the first network hydrogel raw material polyetherimide to the second network hydrogel raw material acrylic acid is 2:1.

[0051] Cyclic voltammetric response results are as follows Figure 7 As shown in the figure, it can be seen that the cyclic voltammetric responses of Example 1 and Comparative Example 2 in a 0.2 M potassium chloride solution containing 4 mM glucose are comparable, which proves that the change in the ratio of the two hydrogels has little effect on the response current.

[0052] Working time stability results are as follows Figure 8 As shown in the figure, the biosensor obtained in Example 1 showed no decay in current response after 24 hours in a 0.2 M potassium chloride solution containing 4 mM glucose, while the biosensor obtained in Comparative Example 2 had decayed by 67%.

[0053] Comparative Example 3 This comparative example refers to Example 1. The materials, steps, and evaluation methods used are the same as in Example 1. The difference is that in step 1), the raw material of the first network hydrogel is polyvinyl imidazole instead of polyetherimide; in step 2), the raw material of the second network hydrogel is polyethylene glycol diacrylate instead of acrylic acid; finally, a biosensor electrode based on polyvinyl imidazole-CHO-Os / polyethylene glycol diacrylate dual network electronic dielectric hydrogel is obtained.

[0054] The biosensor electrodes obtained in Comparative Example 3 and Example 1 were subjected to working time stability tests, and the results are as follows: Figure 9As shown, the results indicate that after 4 days of measurement, the response current of Example 1 in a 0.2 M potassium chloride solution containing 4 mM glucose remained at 97% of that on day 0; while in Comparative Example 3, the response current dropped to 81% of that on day 0 after 1 day of measurement, and further to 61% of that on day 0 after 4 days, showing a significant decrease. These results demonstrate that the glucose current response stability of the biosensor electrode based on polyetherimide-CHO-Os / polyacrylic acid dual-network electronic dielectric hydrogel obtained in Example 1 is significantly better than that of the biosensor electrode based on polyvinylimidazole-CHO-Os / polyethylene glycol diacrylate dual-network electronic dielectric hydrogel obtained in Comparative Example 3, exhibiting excellent electrode operational stability.

[0055] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A biosensor electrode based on a dual-network hydrogel, characterized in that, The invention comprises an electrode substrate and a oxidoreductase-loaded dual-network hydrogel on the surface of the electrode substrate; the oxidoreductase-loaded dual-gel network is obtained by mixing a first network hydrogel precursor solution containing oxidoreductase and a second network hydrogel stock solution and then photocuring the mixture; the first network hydrogel and the second network hydrogel are interpenetrating network structures obtained through physical cross-linking; wherein: The first network hydrogel precursor solution was obtained by mixing polyetherimide, CHO-Os, crosslinking agent and oxidoreductase and then allowing it to react statically. The second network hydrogel stock solution includes acrylic monomers and photoinitiators.

2. The biosensor electrode according to claim 1, characterized in that, In the dual-network hydrogel, the mass ratio of the polyetherimide used in the first network to the acrylic monomer used in the second network is 0.5~1.5:

1.

3. The biosensor electrode according to claim 1, characterized in that, In the first network hydrogel precursor solution, the mass ratio of crosslinking agent to polyetherimide is 0.05~2:1; the mass ratio of CHO-Os electron mediator to polyetherimide is 2~10:1; the mass ratio of oxidoreductase to polyetherimide is 1~5:1; in the second network hydrogel stock solution, the mass ratio of photoinitiator to acrylic monomer is 0.002~0.05:

1.

4. The biosensor electrode according to claim 1, characterized in that, In the first network hydrogel precursor solution, the crosslinking agent is one of glutaraldehyde, polyethylene glycol diglycidyl ether and its derivatives; the oxidoreductase is glucose oxidase or urate oxidase; in the second network hydrogel stock solution, the photoinitiator is photoinitiator 2959.

5. The biosensor electrode according to claim 1, characterized in that, The thickness of the dual-network hydrogel is 50~200μm; the biosensor electrode also includes a protective layer covering the surface of the dual-network hydrogel.

6. The biosensor electrode according to claim 5, characterized in that, The protective layer is made of at least one of Nafion or polyurethane.

7. A method for fabricating a biosensor electrode based on a dual-network hydrogel as described in any one of claims 1-6, characterized in that, Includes the following steps: 1) Polyetherimide and CHO-Os were dissolved in water to prepare a first network hydrogel stock solution; a photoinitiator and acrylic acid were mixed and dissolved in water to prepare a second network hydrogel stock solution; 2) Add an aqueous solution of oxidoreductase and an aqueous solution of crosslinking agent to the first network hydrogel stock solution obtained in step 1), stir evenly, and let it stand to react to obtain the first network hydrogel precursor solution; 3) Add the second network hydrogel stock solution obtained in step 1) to the first network hydrogel precursor solution obtained in step 2), stir evenly to form a double network hydrogel precursor solution; wherein the mass ratio of polyetherimide to acrylic acid is 0.5~1.5:1; 4) Drop the dual-network hydrogel precursor liquid obtained in step 3) onto the electrode substrate, irradiate with ultraviolet light and then dry to obtain the biosensor electrode based on the dual-network hydrogel.

8. The preparation method according to claim 7, characterized in that, In step 2), the reaction time after adding the crosslinking agent is 1~10 min; in step 4), the irradiation power is 100~500 W and the irradiation time is 5~50 s; in step 4), a protective layer is sprayed on, which covers the surface of the dual-network hydrogel to obtain a biosensor electrode based on the dual-network hydrogel.

9. The preparation method according to claim 7, characterized in that, In step 4), the volume ratio of the dual-network hydrogel precursor solution to the electrode area is 1 μL : 0.01~0.03 cm². 2 .

10. The application of the biosensor electrode based on a dual-network hydrogel as a working electrode according to any one of claims 1-6 in the field of biosensors.

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