Core-shell structure type working electrode of electrochemical glucose sensor and preparation method thereof

Abstract

The application belongs to the field of glucose sensors, and discloses a core-shell structure type working electrode of an electrochemical glucose sensor and a preparation method, which comprises the following steps: sputtering a gold film and a ZnO film on a substrate in sequence to obtain a pretreated substrate; placing the pretreated substrate in a ZnO growth solution, growing ZnO nanoflowers on the ZnO film by using a water bath method, and then depositing an AZO film on the ZnO nanoflowers by using an atomic layer deposition technology to obtain an AZO-ZnO nanoflower core-shell structure; and solidifying glucose oxidase on the AZO-ZnO nanoflower core-shell structure to obtain the core-shell structure type working electrode of the electrochemical glucose sensor. The AZO film is prepared on the ZnO nanoflower by using the atomic layer deposition technology process, the core-shell structure type working electrode modified by the AZO is formed, the electronic transmission performance of the functionalized surface is enhanced, the electronic transmission efficiency of the working electrode is improved, the rapid transmission of electrons can be realized on the basis of stable enzyme adsorption, and the core-shell structure type working electrode can be used for preparing a high-performance electrochemical glucose sensor.

Description

Technical Field

[0001] This invention belongs to the field of glucose sensors, and relates to a core-shell structure working electrode of an electrochemical glucose sensor and its preparation method. Background Technology

[0002] Electrochemical glucose sensors represent the oldest and most comprehensive system for continuous blood glucose monitoring. Besides electrochemical methods, glucose sensors based on other measurement principles also exist. Among the most typical are chemiluminescent glucose sensors based on the Bruce blue colorimetric principle and optical fiber glucose sensors (OFGS) based on optical measurement principles. Comparing glucose sensors based on different measurement principles reveals that, for Bruce blue colorimetric glucose sensors, thanks to the unique determination method of colorimetric analysis, the trouble caused by external circuitry can be avoided. However, during the luminescence reaction, the chemical reaction between luminol and H₂O₂ requires at least 40 minutes to stabilize. This type of sensor has poor real-time detection, making it difficult to meet the functional requirements of continuous blood glucose monitoring in new glucose sensors. Glucose sensors based on the colorimetric principle face significant challenges. Optical fiber glucose sensors have become a hot research area in recent years. The basic detection principle of OFGS is mainly based on the spectral characteristics of glucose in the specific mid-infrared region; its absorption of a specific wavelength of light changes with the glucose concentration.

[0003] However, optical-based detection methods are susceptible to interference from ambient light, and their detection efficiency and accuracy need further improvement. Electrochemical sensors offer significant advantages such as fast response, high sensitivity, and accurate measurement, and are also the oldest and most well-established glucose detection system. However, significant research challenges remain in the development of electrochemical glucose sensors. Furthermore, signal processing in electrochemical sensors relies on the electrode system and external circuitry, posing significant challenges to real-time sensing and flexible applications. Additionally, the working electrodes of current electrochemical sensors are typically planar, resulting in a small specific surface area, which leads to low surface electron transport efficiency and weak enzyme adsorption performance. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a core-shell structure working electrode for an electrochemical glucose sensor and its preparation method.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] In a first aspect, the present invention provides a method for preparing a core-shell structured working electrode for an electrochemical glucose sensor, comprising:

[0007] A gold film and a ZnO film were sequentially sputtered onto the substrate to obtain a pretreated substrate.

[0008] The pretreated substrate was placed in a ZnO growth solution, and ZnO nanoflowers were grown on the ZnO film using a water bath method. Then, an AZO film was deposited on the ZnO nanoflowers using atomic layer deposition technology to obtain an AZO-ZnO nanoflower core-shell structure.

[0009] Glucose oxidase was immobilized on the core-shell structure of AZO-ZnO nanoflowers to obtain a core-shell structure working electrode for an electrochemical glucose sensor.

[0010] Optionally, the sequential sputtering of a gold film and a ZnO film on the substrate includes:

[0011] An ion sputtering deposition machine was used to sputter a gold film with a thickness of 50–100 nm onto the substrate;

[0012] Then, a ZnO thin film with a thickness of about 50-100 nm was sputtered onto the gold film using a magnetron sputtering machine.

[0013] Optionally, the ZnO growth solution is prepared in the following manner:

[0014] Hexamethylenetetramine and zinc nitrate hexahydrate were dissolved in deionized water at a mass ratio of 1:2-3 to obtain a ZnO growth solution; wherein, the ZnO growth solution contains Zn 2+ The concentration is 20-30 mM.

[0015] Optionally, the step of placing the pretreated substrate in a ZnO growth solution and growing ZnO nanoflowers on the ZnO film using a water bath method includes:

[0016] When the ZnO growth solution is stirred and heated until it becomes a white suspension, the pretreated substrate is placed in the ZnO growth solution and then placed in a water bath at 80℃-100℃ for 1.5-3 hours.

[0017] Optionally, when depositing AZO thin films on ZnO nanoflowers using atomic layer deposition technology, trimethylaluminum is used as the aluminum source, diethylzinc is used as the zinc source, and water is used as the oxygen precursor source; wherein, the pulse time of trimethylaluminum and diethylzinc is 0.1-0.3s, and the cleaning time is 5-10s; the pulse time of water is 0.1-0.3s, and the cleaning time is 5-10s.

[0018] Optionally, the Al concentration in the AZO film is expressed as the recycling percentage of Al2O3, which is 65%-75%.

[0019] Optionally, the annealing temperature after the AZO film growth is completed is 100-120°C, and the thickness is 8-12 nm.

[0020] Optionally, the immobilization of glucose oxidase on the AZO-ZnO nanoflower core-shell structure includes:

[0021] The concentration is 35–55 mg / ml -1 A GOx solution was spin-coated onto the surface of the AZO-ZnO nanoflower core-shell structure and then naturally dried in air at 5–15°C to obtain the AZO-ZnO nanoflower core-shell structure modified with GOx.

[0022] Nafion solution was coated onto a GOx-modified AZO-ZnO nanoflower core-shell structure to obtain a core-shell structure working electrode for an electrochemical glucose sensor.

[0023] Optionally, the substrate is a PET substrate; when sputtering a gold film and a ZnO film sequentially on the substrate, the substrate after sputtering the gold film is cut into a rectangle of 0.5-1cm × 2-2.5cm, and then the ZnO film is sputtered.

[0024] In a second aspect, the present invention provides a core-shell structure working electrode for an electrochemical glucose sensor, wherein the core-shell structure working electrode for the electrochemical glucose sensor is prepared by the above-described method for preparing a core-shell structure working electrode for an electrochemical glucose sensor.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] This invention discloses a method for fabricating a core-shell structured working electrode for an electrochemical glucose sensor. The method employs an ion sputtering combined with a water bath method to prepare a ZnO nanoflower-like functional surface with a three-dimensional structure at the nanoscale. This increases the specific surface area of ​​the sensor's working electrode, and the three-dimensional structure enables stable adsorption and solidification of glucose oxidase. Simultaneously, an AZO thin film is prepared on the ZnO nanoflowers using atomic layer deposition (ALD) technology, forming an AZO-modified core-shell structured working electrode. This enhances the electron transport performance of the functionalized surface and improves the electron transport efficiency of the working electrode. The core-shell structured working electrode can achieve rapid electron transport while maintaining stable enzyme adsorption, and can be used to fabricate high-performance electrochemical glucose sensors. Attached Figure Description

[0027] Figure 1 This is a morphological diagram of the ZnO nanoflower structure in an embodiment of the present invention.

[0028] Figure 2 This is a transmission electron microscope (TEM) image of the AZO-ZnO nanoflower core-shell structure according to an embodiment of the present invention.

[0029] Figure 3 This is an EDS image of the core-shell structure of the AZO-ZnO nanoflower according to an embodiment of the present invention.

[0030] Figure 4 This is a time-current response curve of the core-shell structure working electrode of the electrochemical glucose sensor according to an embodiment of the present invention. Detailed Implementation

[0031] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0032] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0033] The present invention will now be described in further detail with reference to the accompanying drawings:

[0034] In one embodiment of the present invention, a method for fabricating a core-shell structured working electrode for an electrochemical glucose sensor is provided. A combined water bath method and ALD process are used to fabricate an electrochemical sensor working electrode with an AZO-ZnO nanoflower core-shell structure, achieving a linear response to glucose concentration within a certain range. This method can be applied to the fabrication of high-performance electrochemical sensors. Specifically, the method for fabricating the core-shell structured working electrode for the electrochemical glucose sensor includes the following steps:

[0035] Step 1: Sputter a gold film and a ZnO film sequentially onto the substrate to obtain a pretreated substrate.

[0036] Step 2: Place the pretreated substrate in a ZnO growth solution and grow ZnO nanoflowers on the ZnO film using a water bath method. Then, deposit an AZO film on the ZnO nanoflowers using atomic layer deposition technology to obtain an AZO-ZnO nanoflower core-shell structure.

[0037] Step 3: Immobilize glucose oxidase on the AZO-ZnO nanoflower core-shell structure to obtain the core-shell structure working electrode of the electrochemical glucose sensor.

[0038] In one possible implementation, the sequential sputtering of a gold film and a ZnO film on the substrate includes: using an ion sputtering deposition machine to sputter a gold film with a thickness of 50-100 nm on the substrate; and then using a magnetron sputtering machine to sputter a ZnO film with a thickness of approximately 50-100 nm on the gold film.

[0039] In one possible embodiment, the ZnO growth solution is prepared by dissolving hexamethylenetetramine and zinc nitrate hexahydrate in deionized water at a mass ratio of 1:2-3 to obtain the ZnO growth solution; wherein, the ZnO growth solution contains Zn 2+ The concentration is 20-30 mM.

[0040] In one possible implementation, the step of placing the pretreated substrate in a ZnO growth solution and growing ZnO nanoflowers on a ZnO film using a water bath method includes: stirring and heating the ZnO growth solution until it becomes a white suspension, placing the pretreated substrate in the ZnO growth solution, and placing it in a water bath at 80-100°C for 1.5-3 hours for water bath growth.

[0041] In one possible implementation, when depositing AZO thin films on ZnO nanoflowers using atomic layer deposition (ALD), trimethylaluminum is used as the aluminum source, diethylzinc is used as the zinc source, and water is used as the oxygen precursor source. The pulse duration for trimethylaluminum and diethylzinc is 0.1–0.3 s, and the rinsing time is 5–10 s. The pulse duration for water is 0.1–0.3 s, and the rinsing time is 5–10 s.

[0042] In one possible implementation, the Al concentration in the AZO film is expressed as the recycling percentage of Al2O3, which is 65%–75%. The prepared AZO film is annealed at 100–120°C and has a thickness of 8–12 nm.

[0043] In one possible implementation, the immobilization of glucose oxidase on the AZO-ZnO nanoflower core-shell structure comprises:

[0044] The concentration is 35–55 mg / ml -1A GOx solution was spin-coated onto the surface of an AZO-ZnO nanoflower core-shell structure, and then naturally dried in air at 5–15°C to obtain a GOx-modified AZO-ZnO nanoflower core-shell structure. Nafion solution was then coated onto the GOx-modified AZO-ZnO nanoflower core-shell structure to obtain a core-shell structure working electrode for an electrochemical glucose sensor.

[0045] In one possible implementation, the substrate is a PET substrate; when sputtering a gold film and a ZnO film sequentially on the substrate, the substrate after sputtering the gold film is cut into a rectangle of 0.5-1cm × 2-2.5cm, and then the ZnO film is sputtered.

[0046] In another embodiment of the present invention, a core-shell structure working electrode for an electrochemical glucose sensor is provided, wherein the core-shell structure working electrode for the electrochemical glucose sensor is prepared by the above-described preparation method for the core-shell structure working electrode for an electrochemical glucose sensor.

[0047] The following examples illustrate the method for preparing electrodes for an electrochemical glucose sensor based on a patterned structure according to the present invention.

[0048] Example 1

[0049] Step 1: Substrate preparation.

[0050] The PET substrate was cleaned with anhydrous ethanol solution to remove surface impurities, followed by repeated rinsing with deionized water to remove any remaining solution. The prepared substrate was then placed in a super-clean room (maintained at a constant temperature of 22°C) until completely dry. Next, a 100 nm thick gold film was sputtered onto the PET substrate using an ion sputtering machine (MC1000, 20W power, 60s deposition time) to modify the surface morphology and improve the substrate's conductivity, resulting in an Au / PET substrate. Finally, the Au / PET substrate was cut into 0.5 cm × 2 cm rectangles to form the substrate material for the working electrode.

[0051] Step 2: Preparation of ZnO nanoflower structures by water bath method.

[0052] A ZnO thin film with a thickness of 100 nm was sputtered on an Au / PET substrate using a magnetron sputtering machine to obtain a ZnO / Au / PET substrate, which served as the nucleation layer for ZnO nanoflowers. The magnetron sputtering power was set to 100 W and the working pressure was 10 mTorr. Argon gas flow was ensured during the sputtering process.

[0053] Then, 0.35 g of hexamethylenetetramine and 0.75 g of zinc nitrate hexahydrate were dissolved in 100 ml of deionized water to obtain a ZnO growth solution, while maintaining the Zn content in the ZnO growth solution. 2+ The concentration was 25 mM.

[0054] The ZnO growth solution was heated and stirred in a magnetic stirrer until the temperature reached 90°C. When the ZnO growth solution became a white suspension, the ZnO / Au / PET substrate was quickly immersed in the growth solution and placed in a 90°C water bath for 2.5 hours to prepare ZnO nanoflower structures. The substrate was then removed and air-dried at room temperature in a clean environment. The substrate surface was then repeatedly rinsed with deionized water. The ZnO nanoflower structures grew firmly on the ZnO / Au / PET substrate, thus forming a ZnONFs / Au / PET substrate. (See also...) Figure 1 The image shows the morphology of the ZnO nanoflower structure prepared in this embodiment.

[0055] Step 3: An AZO (aluminum-doped ZnO) thin film is deposited on the surface of ZnO nanoflowers using atomic layer deposition technology to prepare an AZO-ZnO nanoflower core-shell structure.

[0056] In this embodiment, when depositing AZO thin films on ZnO nanoflowers using atomic layer deposition (ALD), trimethylaluminum was used as the aluminum source, diethylzinc as the zinc source, and water as the oxygen precursor source. The pulse duration for trimethylaluminum and diethylzinc was 0.1 s, and the rinsing time was 7 s; the pulse duration for water was 0.1 s, and the rinsing time was 8 s. Furthermore, the Al concentration in the AZO thin film was expressed as the Al2O3 cycling percentage. In this embodiment, the Al2O3 cycling percentage was 70%, the annealing temperature was 120°C, and the AZO thin film thickness was 10 nm.

[0057] See Figure 2 and 3 The TEM results of the AZO-ZnO nanoflower core-shell structure are shown.

[0058] Example 2

[0059] Step 1: Substrate preparation.

[0060] The PET substrate was cleaned with anhydrous ethanol solution to remove surface impurities, followed by repeated rinsing with deionized water to remove any remaining solution. The prepared substrate was then placed in a super-clean room (maintained at a constant temperature of 22°C) until completely dry. Next, a 50 nm thick gold film was sputtered onto the PET substrate using an ion sputtering machine (MC1000, 20W power, 60s deposition time) to modify the surface morphology and improve the substrate's conductivity, resulting in an Au / PET substrate. Finally, the Au / PET substrate was cut into 1.0 cm × 2 cm rectangles to form the substrate material for the working electrode.

[0061] Step 2: Preparation of ZnO nanoflower structures by water bath method.

[0062] A ZnO thin film with a thickness of 50 nm was sputtered on an Au / PET substrate using a magnetron sputtering machine to obtain a ZnO / Au / PET substrate, which served as the nucleation layer for ZnO nanoflowers. The magnetron sputtering power was set to 100 W and the working pressure was 10 mTorr. Argon gas flow was ensured during the sputtering process.

[0063] Then, 0.28 g of hexamethylenetetramine and 0.652 g of zinc nitrate hexahydrate were dissolved in 100 ml of deionized water to obtain a ZnO growth solution, while maintaining the Zn content in the ZnO growth solution. 2+ The concentration was 20 mM.

[0064] The ZnO growth solution was heated and stirred in a magnetic stirrer until the temperature reached 80°C. When the ZnO growth solution became a white suspension, the ZnO / Au / PET substrate was quickly immersed in the growth solution and placed in an 80°C water bath for 2 hours to prepare ZnO nanoflower structures. The substrate was then removed and air-dried at room temperature in an ultra-clean environment. The substrate surface was then repeatedly rinsed with deionized water. The ZnO nanoflower structures grew firmly on the ZnO / Au / PET substrate, thus forming a ZnONFs / Au / PET substrate.

[0065] Step 3: An AZO (aluminum-doped ZnO) thin film is deposited on the surface of ZnO nanoflowers using atomic layer deposition technology to prepare an AZO-ZnO nanoflower core-shell structure.

[0066] In this embodiment, when depositing AZO thin films on ZnO nanoflowers using atomic layer deposition (ALD), trimethylaluminum was used as the aluminum source, diethylzinc as the zinc source, and water as the oxygen precursor source. The pulse duration for trimethylaluminum and diethylzinc was 0.2 s, and the rinsing time was 5 s; the pulse duration for water was 0.2 s, and the rinsing time was 5 s. Furthermore, the Al concentration in the AZO thin film was expressed as the Al2O3 cycling percentage. In this embodiment, the Al2O3 cycling percentage was 65%, the annealing temperature was 100°C, and the AZO thin film thickness was 8 nm.

[0067] Example 3

[0068] Step 1: Substrate preparation.

[0069] The PET substrate was cleaned with anhydrous ethanol solution to remove surface impurities, followed by repeated rinsing with deionized water to remove any remaining solution. The prepared substrate was then placed in a super-clean room (maintained at a constant temperature of 22°C) until completely dry. Next, an 80nm thick gold film was sputtered onto the PET substrate using an ion sputtering machine (MC1000, 20W power, 40s deposition time) to modify the surface morphology and improve the substrate's conductivity, resulting in an Au / PET substrate. Finally, the Au / PET substrate was cut into 0.5cm × 2.5cm rectangles to form the substrate material for the working electrode.

[0070] Step 2: Preparation of ZnO nanoflower structures by water bath method.

[0071] A ZnO thin film with a thickness of 80 nm was sputtered on an Au / PET substrate using a magnetron sputtering machine to obtain a ZnO / Au / PET substrate, which served as the nucleation layer for ZnO nanoflowers. The magnetron sputtering power was set to 100 W and the working pressure was 10 mTorr. Argon gas flow was ensured during the sputtering process.

[0072] Then, 0.6 g of hexamethylenetetramine and 1.8 g of zinc nitrate hexahydrate were dissolved in 100 ml of deionized water to obtain a ZnO growth solution, while maintaining the Zn content in the ZnO growth solution. 2+ The concentration was 30 mM.

[0073] The ZnO growth solution was heated and stirred in a magnetic stirrer until the temperature reached 100°C. When the ZnO growth solution became a white suspension, the ZnO / Au / PET substrate was quickly immersed in the growth solution and placed in a 100°C water bath for 3 hours to prepare ZnO nanoflower structures. The substrate was then removed and air-dried at room temperature in an ultra-clean environment. The substrate surface was then repeatedly rinsed with deionized water. The ZnO nanoflower structures grew firmly on the ZnO / Au / PET substrate, thus forming a ZnONFs / Au / PET substrate.

[0074] Step 3: An AZO (aluminum-doped ZnO) thin film is deposited on the surface of ZnO nanoflowers using atomic layer deposition technology to prepare an AZO-ZnO nanoflower core-shell structure.

[0075] In this embodiment, when depositing AZO thin films on ZnO nanoflowers using atomic layer deposition (ALD), trimethylaluminum was used as the aluminum source, diethylzinc as the zinc source, and water as the oxygen precursor source. The pulse duration for trimethylaluminum and diethylzinc was 0.2 s, and the rinsing time was 10 s; the pulse duration for water was 0.2 s, and the rinsing time was 10 s. Furthermore, the Al concentration in the AZO thin film was expressed as the Al2O3 cycling percentage. In this embodiment, the Al2O3 cycling percentage was 75%, the annealing temperature was 110°C, and the AZO thin film thickness was 12 nm.

[0076] In one possible implementation, the core-shell structure working electrode of the electrochemical glucose sensor prepared in Examples 1 to 3 of the present invention is subjected to glucose response testing.

[0077] The test was conducted using a three-electrode system on a CHI660 electrochemical workstation. The operating voltage was set to 0.8V, and the counter electrode (Pt) and reference electrode (Ag / AgCl) were used.

[0078] First, the core-shell structure working electrode of the prepared electrochemical glucose sensor was initialized by immersing it in 50 ml of PBS buffer and allowed to stand for 40 minutes to reach a stable detection state. Then, 3 mM glucose solution was added to the detection cell every 30 minutes, and the current response was observed. This process was repeated until the current response saturated. The final sensor response curve is shown below. Figure 4 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 results indicate that the core-shell structure sensor prepared using this invention can achieve linear recognition of glucose within a certain concentration range, and the sensor's measurement sensitivity is 2.13 μA·mM. -1 ·cm -2 .

[0079] In summary, the method for fabricating the core-shell structured working electrode of the electrochemical glucose sensor of this invention employs an ion sputtering combined with a water bath method to prepare a ZnO nanoflower-like functional surface with a three-dimensional structure at the nanoscale. This increases the specific surface area of ​​the sensor's working electrode, and the three-dimensional structure enables stable adsorption and solidification of glucose oxidase. Simultaneously, by using atomic layer deposition (ALD) technology to prepare an AZO thin film on the ZnO nanoflowers, an AZO-modified core-shell structured working electrode is formed, enhancing the electron transport performance of the functionalized surface and improving the electron transport efficiency of the working electrode. The core-shell structured working electrode can achieve rapid electron transport while maintaining stable enzyme adsorption, and can be used to fabricate high-performance electrochemical glucose sensors.

[0080] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for preparing a core-shell structured working electrode for an electrochemical glucose sensor, characterized in that, include: A gold film and a ZnO film were sequentially sputtered onto the substrate to obtain a pretreated substrate. The pretreated substrate was placed in a ZnO growth solution, and ZnO nanoflowers were grown on the ZnO film using a water bath method. Then, an AZO film was deposited on the ZnO nanoflowers using atomic layer deposition technology to obtain an AZO-ZnO nanoflower core-shell structure. Immobilizing glucose oxidase on the core-shell structure of AZO-ZnO nanoflowers yields a core-shell structure working electrode for an electrochemical glucose sensor. The ZnO growth solution is prepared in the following manner: Hexamethylenetetramine and zinc nitrate hexahydrate were dissolved in deionized water at a mass ratio of 1:2-3 to obtain a ZnO growth solution; wherein, the ZnO growth solution contains Zn 2+ The concentration is 20~30mM; When depositing AZO thin films on ZnO nanoflowers using atomic layer deposition technology, trimethylaluminum is used as the aluminum source, diethylzinc is used as the zinc source, and water is used as the oxygen precursor source.

2. The method for preparing the core-shell structure working electrode of the electrochemical glucose sensor according to claim 1, characterized in that, The sequential sputtering of a gold film and a ZnO thin film on the substrate includes: An ion sputtering deposition machine is used to sputter a gold film with a thickness of 50~100nm onto the substrate; Then, a ZnO thin film with a thickness of 50~100nm was sputtered onto the gold film using a magnetron sputtering machine.

3. The method for preparing the core-shell structure working electrode of the electrochemical glucose sensor according to claim 1, characterized in that, The step of placing the pretreated substrate in a ZnO growth solution and growing ZnO nanoflowers on a ZnO film using a water bath method includes: When the ZnO growth solution is stirred and heated until it becomes a white suspension, the pretreated substrate is placed in the ZnO growth solution and then placed in a water bath at 80℃-100℃ for 1.5~3h.

4. The method for preparing the core-shell structure working electrode of the electrochemical glucose sensor according to claim 1, characterized in that, When depositing AZO thin films on ZnO nanoflowers using atomic layer deposition technology, the pulse time for trimethylaluminum and diethylzinc is 0.1~0.3s, and the cleaning time is 5~10s; the pulse time for water is 0.1~0.3s, and the cleaning time is 5~10s.

5. The method for preparing the core-shell structure working electrode of the electrochemical glucose sensor according to claim 1, characterized in that, The Al concentration in the AZO film is expressed as the recycling percentage of Al2O3, which is 65%-75%.

6. The method for preparing the core-shell structure working electrode of the electrochemical glucose sensor according to claim 1, characterized in that, The annealing temperature after the AZO thin film growth is 100~120℃, and the thickness is 8~12nm.

7. The method for preparing the core-shell structure working electrode of the electrochemical glucose sensor according to claim 1, characterized in that, The glucose oxidase immobilized on the AZO-ZnO nanoflower core-shell structure includes: The concentration is 35~55 mg·ml -1 A GOx solution was spin-coated onto the surface of an AZO-ZnO nanoflower core-shell structure, and then naturally dried in air at 5~15℃ to obtain an AZO-ZnO nanoflower core-shell structure modified with GOx. Nafion solution was coated onto a GOx-modified AZO-ZnO nanoflower core-shell structure to obtain a core-shell structure working electrode for an electrochemical glucose sensor.

8. The method for preparing the core-shell structure working electrode of the electrochemical glucose sensor according to claim 1, characterized in that, The substrate is a PET substrate; when sputtering a gold film and a ZnO film sequentially on the substrate, the substrate after sputtering the gold film is cut into a rectangle of 0.5~1cm×2~2.5cm, and then the ZnO film is sputtered.

9. A core-shell structure working electrode for an electrochemical glucose sensor, characterized in that, The core-shell structure working electrode of the electrochemical glucose sensor is prepared by the method for preparing the core-shell structure working electrode of the electrochemical glucose sensor according to any one of claims 1 to 8.

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