Non-enzyme glucose sensing electrode based on porous biological membrane, preparation method and application

Abstract

The invention belongs to the technical field of glucose sensing, and discloses an enzyme-free glucose sensing electrode based on a porous biological membrane, a preparation method and application, and the sensing electrode comprises a graphite substrate, a conductive silver layer, an egg shell membrane layer, a platinum conductive layer and a ferroferric oxide magnetic nanoparticle layer from bottom to top. The graphite substrate and the egg shell membrane layer are conductively glued through the conductive silver layer, and the structural advantages of the three-dimensional porous microstructure of the egg shell membrane are fully reserved. The platinum conducting layer improves the conductivity of the electrode substrate, and achieves efficient electron transmission performance through the synergistic effect of the platinum conducting layer and ferroferric oxide serving as nano-enzyme. The three-dimensional porous microstructure of the egg shell membrane increases the specific surface area of the surface of the sensor electrode, can provide a stable and solidified substrate for a nano-enzyme catalytic material, greatly enriches the active sites of the sensor working electrode, and ensures rapid and accurate enzyme-free glucose sensing detection. Meanwhile, the sensing electrode has the advantages of being easy to degrade, high in biocompatibility, environmentally friendly and the like.

Description

Technical Field

[0001] This invention belongs to the field of glucose sensing technology, and relates to an enzyme-free glucose sensing electrode based on a porous biomembrane, its preparation method, and its application. Background Technology

[0002] Diabetes is one of the three major chronic diseases threatening human health. Long-term hyperglycemia can lead to a series of serious complications, including kidney failure, vision loss, and cardiovascular and cerebrovascular diseases. Therefore, blood glucose monitoring has gradually become an indispensable part of modern health management. Glucose sensors, as biosensing elements, can convert glucose concentration into a quantifiable detection signal and have become the main technical tool for daily blood glucose monitoring.

[0003] Micro- and nanostructured materials play a crucial role in achieving high-precision glucose sensing. These materials primarily enhance their specific surface area and porosity by constructing three-dimensional surface microstructures, providing strong support for the adsorption of catalytic functional materials, increasing the contact area between the catalytic functional surface and the sample solution, improving the carrier yield of the working electrode, and thus enhancing the catalytic sensing performance of the sensor. Traditional glucose sensors designed using MEMS (Micro-Electro-Mechanical Systems) technology mainly employ three-dimensional structures such as nanospheres, nanorods, and nanoflowers to modify the surface of the working electrode, thereby improving sensing performance. However, with the development of smart wearable technology, these sensors exhibit significant shortcomings in terms of wearing comfort and flexibility, which to some extent limits their practical application.

[0004] Based on differences in catalytic mechanisms, glucose sensors can be divided into enzyme-based and enzyme-free glucose sensors. Enzyme-based glucose sensors offer advantages such as high selectivity and sensitivity in glucose detection, but suffer from insufficient stability and limited lifespan. Enzyme-free glucose sensors, on the other hand, boast advantages such as high stability, rapid response, simple preparation process, low material cost, and strong environmental adaptability. Noble metal materials, with their high catalytic activity and low biotoxicity, are the most common enzyme-free nanocatalytic functional materials; however, their high cost makes it difficult to meet the demands of large-scale market applications. Traditional transition metals and their oxides, while low in cost, have insufficient electron transport performance, which also affects the overall performance of glucose sensors. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an enzyme-free glucose sensing electrode based on a porous biomembrane, its preparation method, and its application.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] In a first aspect, the present invention provides an enzyme-free glucose sensing electrode based on a porous biomembrane, comprising, from bottom to top, a graphite substrate, a conductive silver layer, an eggshell membrane layer, a platinum conductive layer, and a layer of magnetite nanoparticles.

[0008] Optionally, the graphite substrate has a length of 3-6 cm and a width of 0.5-2 cm; the eggshell membrane layer has a length of 2-5 cm and a width of 1-3 cm; the conductive silver layer has a thickness of 10-50 μm; and the magnetite magnetic nanoparticles in the magnetite magnetic nanoparticle layer have a particle size of 10-50 nm.

[0009] In a second aspect, the present invention provides a method for preparing an enzyme-free glucose sensing electrode based on a porous biomembrane, comprising: preparing a graphite substrate and an eggshell membrane; coating a conductive silver paste on the graphite substrate and laying the eggshell membrane flat on the conductive silver paste, allowing it to stand until the conductive silver paste solidifies, forming a composite structure of a graphite substrate, a conductive silver layer and an eggshell membrane layer; magnetron sputtering a platinum conductive layer on the eggshell membrane layer of the composite structure, and spin-coating a layer of magnetite magnetic nanoparticles on the platinum conductive layer to obtain an enzyme-free glucose sensing electrode based on a porous biomembrane.

[0010] Optionally, the preparation of the graphite substrate and eggshell membrane includes: cutting graphite sheets to a set size, immersing them in anhydrous ethanol solution for ultrasonic cleaning, and then drying them to obtain the graphite substrate; cutting eggshell membranes to a set size, rinsing them with deionized water, and then freeze-drying them.

[0011] Optionally, coating the graphite substrate with conductive silver paste includes coating a 10-50 μm layer of conductive silver paste onto the graphite substrate.

[0012] Optionally, the magnetron sputtering of a platinum conductive layer on the composite eggshell membrane layer includes: magnetron sputtering a platinum conductive layer on the composite eggshell membrane layer for 1 to 3 minutes.

[0013] Optionally, the preparation of the magnetite nanoparticle layer by spin coating on the platinum conductive layer includes: spin coating a suspension of 1-5 mg / mL magnetite nanoparticles onto the platinum conductive layer and drying it to form a magnetite nanoparticle layer.

[0014] Optionally, the particle size of the magnetite magnetic nanoparticles in the magnetite magnetic nanoparticle suspension is 10-50 nm.

[0015] Optionally, the step of spin-coating a 1-5 mg / mL iron oxide magnetic nanoparticle suspension onto a platinum conductive layer and drying it includes: spin-coating a 1-5 mg / mL iron oxide magnetic nanoparticle suspension onto a platinum conductive layer and then naturally drying it in air at 15-25°C.

[0016] In a third aspect, the present invention provides an application of the aforementioned enzyme-free glucose sensing electrode based on a porous biomembrane, or the method for preparing the aforementioned enzyme-free glucose sensing electrode based on a porous biomembrane, in an enzyme-free glucose sensor.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] This invention relates to an enzyme-free glucose sensing electrode based on a porous biomembrane. A graphite substrate and an eggshell membrane layer are conductively bonded together with a conductive silver layer, fully preserving the structural advantages of the eggshell membrane's three-dimensional porous microstructure. This increases the specific surface area of ​​the sensor electrode, and the three-dimensional structure provides a stable substrate for the solidification of nanoenzyme catalytic materials, greatly enriching the active sites of the sensor's working electrode. A platinum conductive layer and a layer of magnetite nanoparticles are then deposited on the eggshell membrane layer to form the enzyme-free glucose sensing electrode based on the porous biomembrane. This electrode enables efficient electron transport while maintaining stable nanoenzyme adsorption, achieving rapid and accurate enzyme-free glucose sensing and detection. Furthermore, this enzyme-free glucose sensing electrode based on a porous biomembrane, using the eggshell membrane as the substrate material, possesses advantages such as easy degradation, high biocompatibility, and environmental friendliness, showing broad application prospects and promotional value in the field of biosensing electrodes.

[0019] This invention discloses a method for preparing an enzyme-free glucose sensing electrode based on a porous biomembrane. It utilizes conductive silver paste to achieve conductive bonding between a graphite substrate and an eggshell membrane, fully preserving the structural advantages of the eggshell membrane's three-dimensional porous microstructure. This increases the specific surface area of ​​the sensor electrode, and the three-dimensional structure provides a stable substrate for the solidification of nano-enzyme catalytic materials, significantly enriching the active sites of the sensor's working electrode. Simultaneously, magnetron sputtering deposition enhances the electron transport performance of the sensing electrode, improving its electron transport efficiency. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of an enzyme-free glucose sensing electrode based on a porous biomembrane according to an embodiment of the present invention.

[0021] Figure 2 This is an exploded view of the structure of an enzyme-free glucose sensing electrode based on a porous biomembrane according to an embodiment of the present invention.

[0022] Figure 3 This is a scanning electron microscope image of an eggshell membrane according to an embodiment of the present invention.

[0023] Figure 4 This is a current response curve of an enzyme-free glucose sensing electrode based on a porous biomembrane, according to an embodiment of the present invention.

[0024] Figure 5This is a linear calibration curve of the response current versus glucose concentration for an enzyme-free glucose sensing electrode based on a porous biomembrane according to an embodiment of the present invention.

[0025] Wherein: 1-Enzyme-free glucose sensing electrode; 2-Graphite substrate; 3-Conductive silver layer; 4-Eggshell membrane layer; 5-Platinum conductive layer; 6-Magnetic nanoparticle layer of iron oxide. Detailed Implementation

[0026] To enable those skilled in the art to understand the features and effects of this invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding this invention, and in case of conflict, the definitions in this specification shall prevail. The theories or mechanisms described and disclosed in this invention, whether right or wrong, shall not in any way limit the scope of this invention; that is, the content of this invention can be implemented without being limited by any specific theory or mechanism.

[0027] In this invention, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be regarded as covering and specifically disclosing all possible secondary ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0028] In this invention, unless otherwise specified, the terms "comprising," "including," "containing," "having," or similar terms encompass the meanings of "composed of" and "mainly composed of," for example, "A contains a" encompasses the meanings of "A contains a and others" and "A contains only a." In this invention, for the sake of brevity, not all possible combinations of the various technical features in the various embodiments or examples are described. Therefore, as long as the combinations of these technical features do not contradict each other, the various technical features in the various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0029] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims. The following embodiments use conventional instruments and equipment in the art. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. The following embodiments use various raw materials, and unless otherwise stated, all are conventional commercially available products with specifications in the art. In the specification of this invention and the following embodiments, unless otherwise specified, "%" represents weight percentage, "parts" represents parts by weight, and "ratio" represents weight ratio.

[0030] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. These descriptions are intended to explain the invention and not to limit it.

[0031] See Figure 1 and 2 In one embodiment of the present invention, an enzyme-free glucose sensing electrode based on a porous biomembrane is provided, which can achieve efficient electron transport on the basis of stable nanoenzyme adsorption, and further enable rapid and accurate enzyme-free glucose sensing and detection.

[0032] Specifically, the enzyme-free glucose sensing electrode based on a porous biomembrane of the present invention comprises, from bottom to top, a graphite substrate 2, a conductive silver layer 3, an eggshell membrane layer 4, a platinum conductive layer 5, and a layer of magnetite nanoparticles 6.

[0033] Explanatory, eggshell membrane layer 4 is prepared from the inner membrane of a natural eggshell, see [link to documentation]. Figure 3 The image shows a scanning electron microscope image of the eggshell membrane, which reveals a three-dimensional porous network structure.

[0034] This invention relates to an enzyme-free glucose sensing electrode based on a porous biomembrane. A graphite substrate 2 and an eggshell membrane layer 4 are conductively bonded together by a conductive silver layer 3. This process fully preserves the structural advantages of the eggshell membrane's three-dimensional porous microstructure, increasing the specific surface area of ​​the sensor electrode. The three-dimensional structure provides a stable and solidified substrate for nanoenzyme catalytic materials, greatly enriching the active sites of the sensor's working electrode. A platinum conductive layer 5 and a layer of magnetite nanoparticles 6 are then deposited on the eggshell membrane layer 4 to form the enzyme-free glucose sensing electrode based on the porous biomembrane. This electrode enables efficient electron transport while maintaining stable nanoenzyme adsorption, achieving rapid and accurate enzyme-free glucose sensing and detection. Furthermore, this enzyme-free glucose sensing electrode based on a porous biomembrane, using the eggshell membrane as the substrate material, possesses advantages such as easy degradation, high biocompatibility, and environmental friendliness, showing broad application prospects and promotional value in the field of biosensing electrodes.

[0035] In one possible implementation, the graphite substrate 2 has a length of 3-6 cm and a width of 0.5-2 cm; the eggshell membrane layer 4 has a length of 2-5 cm and a width of 1-3 cm; the conductive silver layer 3 has a thickness of 10-50 μm; and the magnetite magnetic nanoparticle layer 6 has a particle size of 10-50 nm.

[0036] In another embodiment of the present invention, a method for preparing an enzyme-free glucose sensing electrode based on a porous biomembrane is provided, which comprehensively employs conductive bonding, sputtering deposition, and spin coating processes. Specifically, the method for preparing the enzyme-free glucose sensing electrode based on a porous biomembrane of the present invention includes the following steps:

[0037] S1: Preparation of graphite substrate 2 and eggshell membrane.

[0038] S2: Coat the graphite substrate 2 with conductive silver paste and lay the eggshell membrane flat on the conductive silver paste. Let it stand until the conductive silver paste solidifies to form a composite structure of graphite substrate 2, conductive silver layer 3 and eggshell membrane layer 4.

[0039] S3: A platinum conductive layer 5 is magnetron sputtered onto the composite eggshell membrane layer 4, and a magnetic nanoparticle layer 6 of iron oxide is spin-coated onto the platinum conductive layer 5 to obtain an enzyme-free glucose sensing electrode based on a porous biomembrane.

[0040] This invention discloses a method for preparing an enzyme-free glucose sensing electrode based on a porous biomembrane. It utilizes conductive silver paste to achieve conductive bonding between a graphite substrate 2 and an eggshell membrane, fully preserving the structural advantages of the eggshell membrane's three-dimensional porous microstructure. This increases the specific surface area of ​​the sensor electrode, and the three-dimensional structure provides a stable substrate for the solidification of nano-enzyme catalytic materials, significantly enriching the active sites of the sensor's working electrode. Simultaneously, magnetron sputtering deposition enhances the electron transport performance of the sensing electrode, improving its electron transport efficiency.

[0041] In one possible implementation, the preparation of the graphite substrate 2 and the eggshell membrane includes: cutting graphite sheets to a set size, immersing them in anhydrous ethanol solution for ultrasonic cleaning, and then drying them to obtain the graphite substrate 2; cutting the eggshell membrane to a set size, rinsing it with deionized water, and then freeze-drying it.

[0042] For example, when cutting graphite sheets according to a set size, the graphite sheets can be cut into rectangular graphite sheets with a length of 3 to 6 cm and a width of 0.5 to 2 cm. The cut rectangular graphite sheets are immersed in anhydrous ethanol solution and ultrasonically cleaned for 10 to 30 minutes. Then, the cleaned rectangular graphite sheets are dried at room temperature to obtain graphite substrate 2.

[0043] For example, when cutting eggshell membranes to a set size, first take a hard-boiled egg, peel off the shell and remove the inner membrane, remove surface impurities from the inner membrane, and then carefully rinse the inner membrane with deionized water for 5 minutes. Next, flatten the washed inner membrane and place it in a freeze dryer to ensure no moisture remains. Then, cut the inner membrane into rectangles 2–5 cm long and 1–3 cm wide to obtain the pre-treated eggshell membrane.

[0044] In one possible implementation, coating the graphite substrate 2 with conductive silver paste includes coating the graphite substrate 2 with a conductive silver paste of 10-50 μm.

[0045] Specifically, a conductive silver paste with a thickness of approximately 10–50 μm is uniformly coated onto a graphite substrate 2. An eggshell membrane is then laid flat on the surface of the graphite substrate 2 coated with the conductive silver paste, ensuring that there are no air bubbles or voids between them. Under uniform pressure, the conductive silver paste is allowed to dry naturally until it solidifies, achieving a conductive bond between the graphite substrate 2 and the eggshell membrane. Finally, the excess eggshell membrane covering the area outside the graphite substrate 2 is trimmed, resulting in a composite structure (ESM / Ag / GS) ​​consisting of graphite substrate 2 (GS), conductive silver layer 3 (Ag), and eggshell membrane layer 4 (ESM).

[0046] In one possible implementation, the magnetron sputtering of a platinum conductive layer 5 on the composite eggshell membrane layer 4 includes: magnetron sputtering a platinum conductive layer 5 on the composite eggshell membrane layer 4 for 1 to 3 minutes.

[0047] Specifically, a platinum conductive layer 5 was sputtered onto the surface of a composite structure consisting of a graphite substrate 2, a conductive silver layer 3, and an eggshell membrane layer 4 for 1–3 min using a magnetron sputtering machine (MSP-2S) to obtain the substrate material (Pt / ESM / Ag / GS) ​​for an enzyme-free glucose sensing electrode based on a porous biomembrane.

[0048] In one possible implementation, the preparation of the magnetite nanoparticle layer 6 by spin-coating on the platinum conductive layer 5 includes: spin-coating a suspension of 1-5 mg / mL magnetite nanoparticles onto the platinum conductive layer 5 and drying it to form the magnetite nanoparticle layer 6.

[0049] Optionally, the step of spin-coating a 1-5 mg / mL suspension of magnetite nanoparticles onto the platinum conductive layer 5 and drying it includes: spin-coating a 1-5 mg / mL suspension of magnetite nanoparticles onto the platinum conductive layer 5 and allowing it to dry naturally in air at 15-25°C.

[0050] Optionally, the particle size of the magnetite magnetic nanoparticles in the magnetite magnetic nanoparticle suspension is 10–50 nm. For example, it is typically 10 nm, 20 nm, 30 nm, 40 nm, or 50 nm.

[0051] Specifically, a suspension of magnetite magnetic nanoparticles with a concentration of 1–5 mg / mL was spin-coated onto the surface of the substrate material of an enzyme-free glucose sensing electrode based on a porous biomembrane, and then naturally dried in air at 15–25 °C to obtain an enzyme-free glucose sensing electrode modified with magnetite magnetic nanoparticles (Fe3O4MNPs / Pt / ESM / Ag / GS).

[0052] In one possible implementation, the method for preparing the enzyme-free glucose sensing electrode based on a porous biomembrane specifically includes the following detailed steps:

[0053] Step 1: Pretreatment of Graphite Substrate 2 and Eggshell Membrane. Cut graphite sheets into rectangles 3cm long and 1cm wide. Immerse the cut graphite sheets in anhydrous ethanol solution and ultrasonically clean for 20 minutes. Then dry the cleaned graphite sheets at room temperature to obtain pretreated graphite substrate 2. Take a hard-boiled egg, carefully peel off the eggshell and remove the inner membrane, removing surface impurities from the inner membrane, and then rinse thoroughly with deionized water for 5 minutes. Subsequently, flatten the cleaned inner membrane and place it in a freeze dryer to dry, ensuring no moisture residue remains. Cut the inner membrane into rectangles 2.5cm long and 1.5cm wide to obtain pretreated eggshell membrane.

[0054] Step 2: A conductive silver paste with a thickness of approximately 30 μm is uniformly coated onto the graphite substrate 2. The eggshell membrane is then laid flat on the surface of the graphite substrate 2 coated with the conductive silver paste, ensuring that there are no air bubbles or gaps between them. Under uniform pressure, the conductive silver paste is allowed to dry naturally until it solidifies, achieving conductive bonding between the graphite substrate 2 and the eggshell membrane. Finally, the excess eggshell membrane covering the area outside the graphite substrate 2 is trimmed off, resulting in a composite structure of graphite substrate 2, conductive silver layer 3, and eggshell membrane layer 4.

[0055] Step 3: Using a magnetron sputtering machine (MSP-2S), a platinum conductive layer 5 is sputtered onto the surface of the composite structure of graphite substrate 2, conductive silver layer 3 and eggshell membrane layer 4 for 2 minutes to obtain the substrate material of the enzyme-free glucose sensing electrode based on porous biomembrane.

[0056] Step 4: Using a high-precision balance (accuracy 0.001g), weigh 0.25g of 10nm magnetite nanoparticles and dilute to 50mL with deionized water to obtain a magnetite nanoparticle mixed solution with a concentration of approximately 5mg / mL. Place the magnetite nanoparticle mixed solution in an ultrasonic cleaner and ultrasonically disperse it at 100% power for 15min until the mixture presents a uniform and stable suspension, obtaining a magnetite magnetic nanoparticle suspension. Then, spin-coat 10μL of the magnetite magnetic nanoparticle suspension onto a rectangular area of ​​approximately 1cm × 1cm on the surface of the substrate material of the enzyme-free glucose sensing electrode based on a porous biomembrane. Allow it to air dry naturally at 25℃ to obtain the magnetite magnetic nanoparticle modified enzyme-free glucose sensing electrode based on a porous biomembrane.

[0057] In this embodiment, three repeated experiments were conducted. In addition to the experiment mentioned above, the concentrations of the magnetite magnetic nanoparticle suspension in the other two experiments were 1 mg / mL and 3 mg / mL, respectively; the thicknesses of the conductive silver paste were 10 μm and 50 μm, respectively; the magnetron sputtering times for the platinum conductive layer 5 on the composite eggshell membrane layer 4 were 1 min and 3 min, respectively; and the drying temperatures of the magnetite magnetic nanoparticle suspension were 15℃ and 20℃, respectively. The three repeated experiments successfully prepared an enzyme-free glucose sensing electrode based on a porous biomembrane.

[0058] Below, the enzyme-free glucose sensing electrode based on a porous biomembrane prepared by the preparation method of the enzyme-free glucose sensing electrode based on a porous biomembrane in the previous embodiment of the present invention is subjected to glucose response testing.

[0059] A three-electrode system was used, and the tests were performed on a CHI660 electrochemical workstation. The IT response of the electrodes was measured using the current-time (IT) method, with an operating voltage of 0.8V. This invention uses a porous biomembrane-based enzyme-free glucose sensing electrode as the working electrode, and employs a platinum wire (Pt) counter electrode and a silver-silver chloride (Ag / AgCl) reference electrode.

[0060] First, prepare 100 mL of the test buffer solution containing 100 mM sodium hydroxide (NaOH) and 10 mM phosphate buffered saline (PBS, pH 7.4). Then, immerse the prepared three-electrode system (enzyme-free glucose sensing electrode based on a porous biomembrane, platinum wire counter electrode, and silver-silver chloride reference electrode) in the test buffer solution. Start the electrochemical workstation and stabilize the system for 10–60 min until the background current reaches equilibrium. Subsequently, add 200 μL of 0.25 M glucose solution to the test buffer solution every 10 min, recording the current response for 50 s each time. Repeat the above steps until the current response saturates.

[0061] The final current response curve of the sensor is as follows: Figure 4 As shown, the corresponding linear calibration curve of response current versus glucose concentration is as follows: Figure 5 As shown in the figure, the current-time response curve exhibits a stepped structure, and the current increase is basically consistent after adding an equal amount of glucose solution. The test results indicate that the porous biomembrane enzyme-free electrochemical glucose sensor prepared by this invention can identify glucose concentration within a certain linear range, and the measurement sensitivity of the sensor is 380.022 μA·mM. -1 ·cm -2 .

[0062] In summary, the enzyme-free glucose sensing electrode based on porous biomembranes of this invention can achieve efficient electron transport on the basis of stable nanoenzyme adsorption, enabling rapid and accurate enzyme-free glucose sensing and detection. Furthermore, using eggshell membrane as the substrate material has advantages such as easy degradation, high biocompatibility, and environmental friendliness, and has broad application prospects and promotional value in the field of biosensing electrodes.

[0063] In another embodiment of the present invention, an application is provided of the above-mentioned enzyme-free glucose sensing electrode based on a porous biomembrane, or the above-mentioned method for preparing the enzyme-free glucose sensing electrode based on a porous biomembrane, in an enzyme-free glucose sensor. Specifically, when applied in an enzyme-free glucose sensor, this electrode can significantly improve sensing performance, ensure the accuracy and reliability of detection results, and demonstrate broad application prospects and promotional value.

[0064] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0065] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. Technical details not described in detail in this invention can all be implemented using any existing technology in the art. In particular, all technical features not described in detail in this invention can be implemented using any existing technology.

Claims

1. An enzyme-free glucose sensing electrode based on a porous biomembrane, characterized in that, It includes, from bottom to top, a graphite substrate, a conductive silver layer, an eggshell membrane layer, a platinum conductive layer, and a layer of magnetite nanoparticles.

2. The enzyme-free glucose sensing electrode based on a porous biomembrane according to claim 1, characterized in that, The graphite substrate has a length of 3–6 cm and a width of 0.5–2 cm; the eggshell membrane layer has a length of 2–5 cm and a width of 1–3 cm; the conductive silver layer has a thickness of 10–50 μm; and the magnetite magnetic nanoparticles in the magnetite magnetic nanoparticle layer have a particle size of 10–50 nm.

3. A method for preparing an enzyme-free glucose sensing electrode based on a porous biomembrane, characterized in that, include: Preparation of graphite substrate and eggshell membrane; A conductive silver paste is coated on a graphite substrate and an eggshell membrane is laid flat on the conductive silver paste. The substrate is left to stand until the conductive silver paste solidifies, forming a composite structure of a graphite substrate, a conductive silver layer, and an eggshell membrane layer. A platinum conductive layer was magnetron sputtered onto a composite eggshell membrane layer, and a layer of iron oxide magnetic nanoparticles was spin-coated onto the platinum conductive layer to obtain an enzyme-free glucose sensing electrode based on a porous biomembrane.

4. The method for preparing the enzyme-free glucose sensing electrode based on a porous biomembrane according to claim 3, characterized in that, The preparation of the graphite substrate and eggshell membrane includes: Graphite sheets were cut to the set dimensions, immersed in anhydrous ethanol solution, ultrasonically cleaned, and then dried to obtain a graphite substrate; eggshell membranes were cut to the set dimensions, rinsed with deionized water, and then freeze-dried.

5. The method for preparing an enzyme-free glucose sensing electrode based on a porous biomembrane according to claim 3, characterized in that, The process of coating a conductive silver paste onto a graphite substrate includes: A 10–50 μm thick conductive silver paste is coated onto a graphite substrate.

6. The method for preparing an enzyme-free glucose sensing electrode based on a porous biomembrane according to claim 3, characterized in that, The magnetron sputtering of a platinum conductive layer on the composite eggshell membrane layer includes: A platinum conductive layer was magnetron sputtered onto the composite eggshell membrane layer for 1–3 min.

7. The method for preparing an enzyme-free glucose sensing electrode based on a porous biomembrane according to claim 3, characterized in that, The preparation of the iron oxide magnetic nanoparticle layer by spin coating on the platinum conductive layer includes: A suspension of 1–5 mg / mL iron oxide magnetic nanoparticles was spin-coated onto a platinum conductive layer and dried to form an iron oxide magnetic nanoparticle layer.

8. The method for preparing an enzyme-free glucose sensing electrode based on a porous biomembrane according to claim 7, characterized in that, The magnetic nanoparticles in the iron oxide suspension have a particle size of 10–50 nm.

9. The method for preparing an enzyme-free glucose sensing electrode based on a porous biomembrane according to claim 7, characterized in that, The step of spin-coating a 1-5 mg / mL iron oxide magnetic nanoparticle suspension onto a platinum conductive layer and drying it includes: spin-coating a 1-5 mg / mL iron oxide magnetic nanoparticle suspension onto a platinum conductive layer and then naturally drying it in air at 15-25°C.

10. The application of the enzyme-free glucose sensing electrode based on a porous biomembrane as described in claim 1 or 2, or the preparation method of the enzyme-free glucose sensing electrode based on a porous biomembrane as described in any one of claims 3 to 7, in an enzyme-free glucose sensor.

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