A glucose sensor based on composite film and a preparation method thereof

Abstract

The present application relates to the technical field of biosensor, especially to a glucose sensor based on composite film and a preparation method thereof, after fixing layered MoS2 semiconductor material on a substrate, the present application continues to prepare ion gel film on the substrate, then modifies glucose oxidase on the surface of the ion gel film, after incubation and fixation, modifies a layer of Nafion film on the surface of the ion gel film, because glucose oxidase oxidizes and decomposes glucose to generate protons, with the selective proton passing effect of the Nafion film, the protons pass through the Nafion film to the porous network structure formed by the ion gel film and the layered MoS2 semiconductor material, and cooperate with the cations in the ion gel film to attract more carriers, and form a double-layer structure on the surface of MoS2, cooperate with the current multiplication effect, improve the transmission efficiency of the carriers, and improve the sensitivity of the sensor.

Description

Technical Field

[0001] This invention relates to the field of biosensor technology, and in particular to a glucose sensor based on a composite thin film and its preparation method. Background Technology

[0002] Glucose is an important biomarker for the diagnosis of diabetes, and its detection methods are mainly divided into optical detection methods and electrochemical detection methods. Among them, optical detection methods mainly include photoacoustic spectroscopy, Raman spectroscopy, fluorescence spectroscopy, and near-infrared spectroscopy.

[0003] Optical detection methods, because they do not require reagents in the glucose detection process, offer a significantly longer lifespan for the optical sensors compared to electrochemical detection sensors. However, optical detection methods have several drawbacks: 1. Low sensitivity, making it impossible to measure at physiological concentrations; 2. Weak optical signals, susceptible to severe interference from external noise; 3. The equipment required for optical detection methods is complex, bulky, and difficult to carry, making it inconvenient to use.

[0004] Electrochemical detection methods are primarily based on amperometric enzyme electrodes. Due to the high sensitivity and selectivity of enzyme electrodes, they play a crucial role in monitoring blood glucose levels; therefore, electrochemical detection is considered the most widely used method for glucose detection. Currently, most electrochemical detection methods employ passive bioelectrodes, which offer advantages such as miniaturization and portability. However, the extremely low glucose concentration in body fluids results in minimal changes in electrode impedance, significantly limiting the detection range of passive bioelectrodes for glucose.

[0005] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a glucose sensor based on a composite thin film and its preparation method, aiming to solve the problem that existing glucose sensors have low sensitivity and cannot detect glucose at extremely low concentrations.

[0007] The technical solution of the present invention is as follows:

[0008] A method for fabricating a glucose sensor based on a composite thin film includes the following steps:

[0009] MoS2 was mixed with an organic solvent and then subjected to ultrasonic disruption and centrifugation to obtain layered MoS2.

[0010] The layered MoS2 was mixed with water to obtain a MoS2 suspension;

[0011] The MoS2 suspension was coated onto a substrate and then annealed and dried to obtain a pretreated substrate.

[0012] The polymer crosslinking agent, ionic liquid and acetone are mixed and spin-coated onto the pretreated substrate, and then dried to obtain an ion gel film on the pretreated substrate.

[0013] The ion gel film was modified sequentially with glucose oxidase and perfluorosulfonic acid-polytetrafluoroethylene copolymer to obtain the glucose sensor based on the composite film.

[0014] The method for preparing a glucose sensor based on a composite thin film, wherein the step of mixing MoS2 with an organic solvent and then subjecting it to ultrasonic disruption and centrifugation specifically includes the following steps:

[0015] After mixing the MoS2 with the organic solvent, the mixture is subjected to a first ultrasonic disruption and a first centrifugation process to obtain a first precipitate.

[0016] The first precipitate was mixed with the organic solvent and then subjected to a second ultrasonic crushing and a second centrifugation process.

[0017] The method for preparing a glucose sensor based on a composite thin film, wherein the ultrasonic breaking temperature is 0-4℃.

[0018] The method for preparing the glucose sensor based on the composite thin film, wherein the annealing and drying treatment is performed at a temperature of 45-60℃ for 1-2 hours.

[0019] The method for preparing the glucose sensor based on the composite thin film, wherein the polymer crosslinking agent is at least one selected from polyvinylidene fluoride copolymer, formaldehyde, titanium dioxide, and sulfides; and the ionic liquid is [EMIM]. + [TFSI] - At least one of the following: propamidomethylimidazolium ionic liquid, 1-butoxy-3-methylimidazolium, and butyl sulfonate.

[0020] The method for preparing a glucose sensor based on a composite thin film, wherein the mass ratio of the polymer crosslinking agent, the ionic liquid, and the acetone is 1:(4-5):(6-8).

[0021] The method for preparing the glucose sensor based on the composite film, wherein the drying temperature is 65-75℃ and the drying time is 22-26h.

[0022] The method for preparing a glucose sensor based on a composite film, wherein the step of sequentially modifying the ion gel film with glucose oxidase and perfluorosulfonic acid-polytetrafluoroethylene copolymer specifically includes:

[0023] The glucose oxidase was activated to obtain an activated glucose oxidase solution.

[0024] The activated glucose oxidase solution was coated onto the ion gel film, and after incubation, the modification of the ion gel film by glucose oxidase was completed.

[0025] The perfluorosulfonic acid-polytetrafluoroethylene copolymer was coated onto an ion gel film modified with glucose oxidase, and after drying, the modification of the ion gel film by the perfluorosulfonic acid-polytetrafluoroethylene copolymer was completed.

[0026] The method for preparing the glucose sensor based on the composite film, wherein the concentration of the glucose oxidase is 50-70 mg / mL.

[0027] A glucose sensor based on a composite thin film is prepared using the method for preparing the glucose sensor based on the composite thin film.

[0028] Beneficial Effects: This invention provides a glucose sensor based on a composite thin film and its preparation method. The preparation method includes the following steps: mixing MoS2 with an organic solvent, followed by ultrasonic crushing and centrifugation to obtain layered MoS2; mixing the layered MoS2 with water to obtain a MoS2 suspension; coating the MoS2 suspension onto a substrate and annealing and drying to obtain a pretreated substrate; mixing a polymer crosslinking agent, an ionic liquid, and acetone and spin-coating the mixture onto the pretreated substrate, followed by drying to obtain an ion gel film on the pretreated substrate; and modifying the ion gel film sequentially with glucose oxidase and perfluorosulfonic acid-polytetrafluoroethylene copolymer to obtain the glucose sensor based on the composite thin film. In this invention, after fixing layered MoS2 semiconductor material on the substrate, an ion gel film is prepared on it. Then, glucose oxidase is modified onto the surface of the ion gel film. After incubation and fixation, a Nafion film is modified on it. Since glucose oxidase oxidizes and decomposes glucose into protons, the Nafion film selectively allows protons to pass through it, reaching the porous network structure formed by the ion gel film and the layered MoS2 semiconductor material. This, along with the cations in the ion gel film, induces more charge carriers and forms a double electric layer structure at the interface between MoS2 and the ion gel. This, along with the current multiplication effect, improves the carrier transport efficiency, thereby enhancing the sensor sensitivity and enabling accurate detection of glucose at extremely low concentrations in body fluids. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the process flow for the preparation method of a glucose sensor based on a composite thin film according to the present invention.

[0030] Figure 2 This is a schematic diagram of the structure of a glucose sensor based on a composite thin film according to the present invention;

[0031] Figure 3 This is a schematic diagram illustrating the working principle of a glucose sensor based on a composite thin film according to the present invention.

[0032] Figure 4 These are scanning electron microscope (SEM) images of different modification processes on the surface of the photolithographic electrode in Example 1;

[0033] Figure 5 This is a graph showing the data of glucose concentration dynamically monitored by the glucose sensor in Example 1;

[0034] Figure 6 This is a graph showing the specific characterization data of the glucose sensor in Example 1. Detailed Implementation

[0035] This invention provides a glucose sensor based on a composite thin film and its preparation method. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0036] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0037] like Figure 1 As shown, this invention provides a method for preparing a glucose sensor based on a composite thin film, comprising the following steps:

[0038] Step S10: After mixing MoS2 with an organic solvent, the mixture is subjected to ultrasonic disruption and centrifugation to obtain layered MoS2.

[0039] Step S20: Mix the layered MoS2 with water to obtain a MoS2 suspension;

[0040] Step S30: The MoS2 suspension is coated onto the substrate and then annealed and dried to obtain a pretreated substrate;

[0041] Step S40: The polymer crosslinking agent, ionic liquid and acetone are mixed and spin-coated onto the pretreated substrate, and then dried to obtain an ion gel film on the pretreated substrate;

[0042] Step S50: The ion gel film is modified sequentially using glucose oxidase and perfluorosulfonic acid-polytetrafluoroethylene copolymer to obtain the glucose sensor based on the composite film.

[0043] In this embodiment, a layered n-type semiconductor material prepared by ultrasonic disruption and centrifugation possesses high specific surface area and excellent charge transport characteristics, which can enhance electron transfer efficiency. This provides a foundation for the fabrication of active devices. Coating this material onto a substrate can improve the sensitivity of the sensor and overcome detection limitations. Then, an ion gel film is prepared on the pretreated substrate, and subsequently modified with glucose oxidase (GOx) and perfluorosulfonic acid-polytetrafluoroethylene copolymer (Nafion) to obtain a glucose sensor, the structure of which is as follows. Figure 2 As shown; the working principle of this glucose sensor is as follows. Figure 3 As shown, it utilizes the property of glucose oxidase to specifically recognize glucose molecules and catalyze their decomposition into protons, and the selective passage property of Nafion, which facilitates the selective passage of protons generated after the decomposition of glucose molecules through the network channels inside the ion gel and induces charge carriers in the MoS2 nanosheets, generating a current multiplication effect and changing the current, thus achieving a good synergistic effect.

[0044] Specifically, this embodiment utilizes a whole-solution preparation method to fabricate a glucose sensor based on a layered molybdenum disulfide / ion gel composite film. This sensor can detect extremely low concentrations of glucose with high sensitivity. Furthermore, the fabrication method is simple, low-cost, and highly operable. An active device for glucose concentration detection is prepared using ion gel and layered MoS2. The porous network structure formed by the ion gel and layered MoS2 two-dimensional semiconductor materials, and the double-layer structure formed at the interface between cations in the ion gel and charge carriers in MoS2, improve the carrier transport efficiency, resulting in superior sensitivity and rapid response, thus achieving sensitive glucose detection.

[0045] In some embodiments, the step of mixing MoS2 with an organic solvent and then performing ultrasonic crushing and centrifugation specifically includes the following steps: mixing MoS2 with the organic solvent, performing a first ultrasonic crushing and a first centrifugation to obtain a first precipitate; and mixing the first precipitate with the organic solvent, performing a second ultrasonic crushing and a second centrifugation.

[0046] Specifically, ultrasonic crushing and centrifugation of molybdenum disulfide are performed to remove molybdenum disulfide and obtain layered molybdenum disulfide. Ultrasonic crushing can yield layered n-type semiconductor materials with high specific surface area and good charge transport characteristics. In this embodiment, layered molybdenum disulfide is obtained by multiple ultrasonic crushing and multiple centrifugation processes, which can remove impurities from the raw material and fully remove molybdenum disulfide to obtain few-layer or even single-layer molybdenum disulfide.

[0047] In some embodiments, the power of the first ultrasonic fragmentation is 450W, and the duration is 1 hour; the frequency of the first ultrasonic fragmentation is a duration of 3 seconds with an interval of 2 seconds; the power of the second ultrasonic fragmentation is 450W, and the duration is 5 hours; the frequency of the second ultrasonic fragmentation is a duration of 3 seconds with an interval of 2 seconds. The purpose of the first ultrasonic fragmentation is to initially break down molybdenum disulfide and remove impurities from the original powder; the purpose of the second ultrasonic fragmentation is to fully exfoliate the molybdenum disulfide to obtain a few layers or even a single layer of molybdenum disulfide.

[0048] In some embodiments, the first centrifugation treatment is carried out at a speed of 4500-5000 rpm for 2 hours, which can effectively remove impurities from the original powder; the second centrifugation treatment includes first centrifuging at a speed of 500 rpm for 2 hours; after centrifugation, the supernatant is taken and centrifuged again at a speed of 1000 rpm for 2 hours, which effectively extracts the layered MoS2.

[0049] In some embodiments, the ultrasonic crushing temperature is 0-4°C, which can prevent the temperature from rising continuously during the ultrasonic crushing process, thus avoiding the evaporation of organic solvents.

[0050] In some embodiments, in step S10, the organic solvent may be selected from, but is not limited to, at least one of N-methylpyrrolidone (NMP), polyvinylpyrrolidone (PVP), and N,N-dimethylacetamide (DAMC) to provide an environment for obtaining layered molybdenum disulfide. The concentration of the molybdenum disulfide after mixing with the N-methylpyrrolidone is 50 mg / mL.

[0051] In some embodiments, in step S20, the layered MoS2 is mixed with deionized water, thereby obtaining a MoS2 suspension with fewer impurities, which indirectly improves the sensitivity of the sensor.

[0052] In some embodiments, the annealing and drying treatment temperature is 45-60°C, and the annealing and drying treatment time is 1-2 hours. At this annealing and drying temperature and time, layered molybdenum disulfide can be fixed on the channels of the substrate, so that the layered molybdenum disulfide can be stacked on the channels to form a porous nanonetwork. However, if the temperature is too low, the annealing time will be too long; if the temperature is too high, the molybdenum disulfide will agglomerate, affecting the device performance.

[0053] In some embodiments, the polymer crosslinking agent is at least one selected from polyvinylidene fluoride copolymer (P(VDF-HFP)), formaldehyde, titanium dioxide (TiO2), and sulfides; the ionic liquid is [EMIM]. + [TFSI] - At least one of the following: propamidomethylimidazolium (AMIM) ionic liquid, 1-butoxy-3-methylimidazolium (BOMIM), and hydrogen butyl sulfonate (BHS). P(VDF-HFP), acting as a crosslinking agent, can sufficiently hinge the crystals in the ionic liquid to form a gel, which, after low-temperature curing, forms a thin film. When a voltage is applied across the device, ions in the ionic gel are attracted to the interface between molybdenum disulfide and the ionic gel, and charge carriers and ions undergo electrostatic coupling, thereby forming an electric double layer. This results in a current multiplication effect in the device, improving its sensitivity.

[0054] In some embodiments, the mass ratio of the polymer crosslinking agent, the ionic liquid, and the acetone is 1:(4-5):(6-8); at this mass ratio, P(VDF-HFP), acting as a crosslinking agent, can hinge the crystals in the ionic liquid.

[0055] In a preferred embodiment, the mass ratio of the polymer crosslinking agent, the ionic liquid, and the acetone is 1:4:7, which allows P(VDF-HFP), acting as the crosslinking agent, to sufficiently hinge the crystals in the ionic liquid.

[0056] In some embodiments, in step S40, the drying temperature is 65-75°C and the drying time is 22-26 hours.

[0057] In a preferred embodiment, the drying temperature is 70°C and the drying time is 24 hours.

[0058] In some embodiments, step S50, specifically including the step of modifying the ionogel film sequentially with glucose oxidase and perfluorosulfonic acid-polytetrafluoroethylene copolymer, includes:

[0059] Step S501: Activate the glucose oxidase to obtain an activated glucose oxidase solution;

[0060] Step S502: The activated glucose oxidase solution is coated onto the ion gel film, and after incubation, the modification of the ion gel film by glucose oxidase is completed.

[0061] Step S503: The perfluorosulfonic acid-polytetrafluoroethylene copolymer is coated onto the glucose oxidase-modified ion gel film, and after drying, the modification of the ion gel film by the perfluorosulfonic acid-polytetrafluoroethylene copolymer is completed.

[0062] Specifically, in step S501, the activation treatment of the glucose oxidase includes: mixing bovine serum albumin with glucose oxidase and placing it in PBS buffer, then refrigerating it overnight (at approximately 4°C) to fully activate the glucose oxidase. Bovine serum albumin is used as a stabilizer in the preservation or reaction solution of restriction enzymes or modified enzymes because some enzymes are unstable or have low activity at low concentrations; the addition of bovine serum albumin acts as a "protector" or "carrier." The activation of glucose oxidase refers to the fact that the original enzyme is a lyophilized powder, which needs to be dissolved in PBS buffer for reactivation.

[0063] The fully activated glucose oxidase solution was then dropped onto the ionogel film and incubated in a drying oven at 40-50°C for 2-3 hours. Finally, it was refrigerated overnight at 4°C to ensure that the glucose oxidase was fully immobilized on the ionogel film. This incubation treatment allows for better fixation of glucose oxidase on the ionogel film surface, improving device stability and sensitivity.

[0064] In some embodiments, the concentration of glucose oxidase is 50-70 mg / mL, and the concentration of bovine serum albumin is 20-40 mg / mL; the volume ratio of glucose oxidase to bovine serum albumin is (1-2):1.

[0065] Specifically, a glucose oxidase solution with a concentration of 60 mg / mL and a bovine serum albumin (BSA) solution with a concentration of 30 mg / mL were prepared. The two solutions were thoroughly mixed at a 1:1 volume ratio, and the mixed solution was refrigerated overnight to allow the glucose oxidase to be fully activated.

[0066] In addition, the present invention also provides a glucose sensor based on a composite thin film, which is prepared using the method for preparing the glucose sensor based on the composite thin film.

[0067] In this embodiment, the glucose sensor based on the composite film prepared by the aforementioned method utilizes the catalytic glucose decomposition property of glucose oxidase and the selective ion exchange properties of the perfluorosulfonic acid-polytetrafluoroethylene copolymer (Nafion) membrane. Protons generated from glucose decomposition are transported to the molybdenum disulfide / ion gel interface. At this interface, more charge carriers are induced to electrostatically couple with the protons, thereby constructing a larger capacitance double layer. This causes a change in the device's output current, thus enabling the detection of glucose concentration. The glucose sensor based on the layered molybdenum disulfide / ion gel composite film prepared in this invention exhibits good biocompatibility, high sensitivity, good specificity, and is non-toxic and harmless. It has potential applications in wearable devices that can be attached to the human body to monitor changes in glucose levels in bodily fluids, showing promising prospects in the field of blood glucose monitoring.

[0068] In some embodiments, the composite film-based glucose sensor can be used in the fabrication of wearable devices.

[0069] The following examples further illustrate the present invention in detail. It should also be understood that the following examples are only for further explanation of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention are within the scope of protection of the present invention.

[0070] Example 1

[0071] 1. Preparation of layered molybdenum disulfide

[0072] Step 1: Take 1g of raw MoS2 powder with an original size of about 2μm and 20mL of N-methylpyrrolidone (NMP), add them together in a test tube to prepare a MoS2 suspension;

[0073] Step 2: Place the test tube containing the MoS2 suspension from Step 1 into a large beaker containing ice (0-4℃), and then place it in an ultrasonic homogenizer for homogenization (power 450W; frequency: duration 3s, interval 2s; duration 1h).

[0074] Step 3: Pour the suspension obtained after sonication in Step 2 into a centrifuge tube and centrifuge it at a speed of 5000 rpm for 2 hours.

[0075] Step 4: Take the precipitate obtained after centrifugation in Step 3 and add 20 mL of NMP for dispersion. Place the solution in an ultrasonic homogenizer for homogenization (power 450W; frequency: duration 3s, interval 2s; duration 5h); after ultrasonication, take the suspension and pour it into a centrifuge tube for centrifugation at 500 rpm for 2h; after centrifugation, take the supernatant and place it in a centrifuge tube for centrifugation again at 1000 rpm for 2h.

[0076] Step 5: Add deionized water to the precipitate obtained after centrifugation in step 4 to obtain a MoS2 suspension;

[0077] Step 6: Add 5 μL of MoS2 suspension to the photolithography electrode and place it on a heating stage at 55°C for drying and annealing for 1 hour. Figure 4 In the image, A is a SEM image of layered molybdenum disulfide, which shows that the layered MoS2 has been successfully immobilized on the electrode surface.

[0078] 2. Preparation of ion gel films

[0079] Step S1: Polyvinylidene fluoride copolymer (P(VDF-HFP)) as a polymer crosslinking agent is mixed with acetone at a mass ratio of 1:7, and stirred on a magnetic stirrer at room temperature for 3 hours; after the two components are fully mixed, an ionic liquid ([EMIM]) with a mass four times that of P(VDF-HFP) is added. + [TFSI] - Add the ingredients to the mixture and place it on a magnetic stirrer to mix thoroughly.

[0080] Step S2: The sample obtained in step S1 is dropped onto the MoS2-modified photolithographic electrode and placed on a spin coater. The spin coater is set to a speed of 500 rpm for the first 5 seconds, then increased to 1200 rpm and maintained for 1 minute, so that the sample becomes thin and uniform after processing. The sample is then placed in a vacuum drying oven at 70°C for 24 hours to obtain an ion gel film with the morphology shown in the figure. Figure 4 As shown in B, Figure 4 B in the image is a SEM image of the layered molybdenum disulfide / ion gel composite film.

[0081] 3. Activate glucose oxidase and construct a biosensing interface

[0082] Step 1: Prepare glucose oxidase at a concentration of 60 mg / mL and bovine serum albumin (BSA) at a concentration of 30 mg / mL; mix the two solutions thoroughly at a volume ratio of 1:1, and refrigerate the mixed solution in a refrigerator (4°C) overnight to fully activate the glucose oxidase.

[0083] Step 2: Add 5 μL of the fully activated glucose oxidase solution to the ionogel membrane and incubate it in a 45°C drying oven for 2.5 h. Finally, refrigerate it overnight at 4°C to ensure that the glucose oxidase is fully immobilized on the ionogel.

[0084] Step 3: 3 μL of 5 wt% Nafion was modified onto the ion gel and dried at room temperature to complete the construction of the glucose biosensing interface. Then, a certain voltage was applied to both ends of the device to finally obtain an active glucose sensor based on a layered molybdenum disulfide / ion gel composite film.

[0085] 4. Dynamic detection of glucose sensor

[0086] The constructed sensor was connected to a current source meter, and a voltage of approximately 1.2V was applied across the electrodes. A 25mM glucose solution was continuously added to the electrodes, and the current change of the sensor was recorded using a chronoamperometry method. The results are as follows. Figure 5 As shown in Figure A, the glucose sensor's response to the grape solution is very obvious and stable.

[0087] Furthermore, the prepared sensor was used for dynamic detection of glucose solutions of different concentrations, and the results are as follows: Figure 5 In section B, as shown in the figure, the sensor current change (y) has a linear relationship with the glucose solution concentration (x). Figure 5 Extract the working curve of the sensor from B in the image. Figure 5 In equation C), when the glucose solution concentration ranges from 0 mM to 0.1 mM, the linear equation is y = 1.68448x + 1.11219, R0 2 =0.9579; when the concentration range is 0.1mM-1mM, its linear equation is y = 0.0932x + 1.26372, R 2 =0.958224. Experiments show that this glucose sensor has stable dynamic detection capabilities.

[0088] 5. Characterize the specificity of the glucose sensor.

[0089] In glucose detection, some components in the human body may interfere with the detection, such as dopamine, ascorbic acid, and uric acid. To specifically characterize these components, we used a chronoamperometry method to characterize the fabricated sensor, and the results are as follows: Figure 6 As shown in the figure, the glucose sensor based on a layered molybdenum disulfide / ion gel composite film developed in this embodiment exhibits excellent specificity in the detection of glucose.

[0090] In summary, this invention provides a glucose sensor based on a composite thin film and its preparation method. The preparation method includes the following steps: mixing MoS2 with an organic solvent, followed by ultrasonic crushing and centrifugation to obtain layered MoS2; mixing the layered MoS2 with water to obtain a MoS2 suspension; coating the MoS2 suspension onto a substrate and annealing and drying to obtain a pretreated substrate; mixing a polymer crosslinking agent, an ionic liquid, and acetone and spin-coating the mixture onto the pretreated substrate, followed by drying to obtain an ion gel film on the pretreated substrate; and sequentially modifying the ion gel film with glucose oxidase and perfluorosulfonic acid-polytetrafluoroethylene copolymer to obtain the glucose sensor based on the composite thin film. In this invention, after fixing layered MoS2 semiconductor material on the substrate, an ion gel film is prepared on it. Then, glucose oxidase is modified onto the surface of the ion gel film. After incubation and fixation, a Nafion film is modified on it. Since glucose oxidase oxidizes and decomposes glucose into protons, the Nafion film selectively allows protons to pass through it. This allows protons to reach the porous network structure formed by the ion gel film and the layered MoS2 semiconductor material. In conjunction with the cations in the ion gel film, more charge carriers are induced, and a double electric layer structure is formed on the MoS2 surface. This, along with the current multiplication effect, improves the carrier transport efficiency, thereby enhancing the sensor sensitivity and enabling accurate detection of glucose at extremely low concentrations in body fluids.

[0091] It should be understood that the application of the present invention is not limited to the examples above. 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 method for preparing a glucose sensor based on a composite thin film, characterized in that, Including the following steps: MoS2 was mixed with an organic solvent and then subjected to ultrasonic disruption and centrifugation to obtain layered MoS2. The layered MoS2 was mixed with water to obtain a MoS2 suspension; The MoS2 suspension was coated onto a substrate and then annealed and dried to obtain a pretreated substrate. The polymer crosslinking agent, ionic liquid and acetone are mixed and spin-coated onto the pretreated substrate, and then dried to obtain an ion gel film on the pretreated substrate. The ion gel film was modified sequentially with glucose oxidase and perfluorosulfonic acid-polytetrafluoroethylene copolymer to obtain the glucose sensor based on the composite film. The polymer crosslinking agent is at least one selected from polyvinylidene fluoride copolymer, formaldehyde, titanium dioxide, and sulfides; the ionic liquid is [EMIM]. + [TFSI] - At least one of the following: propamidomethylimidazolium ionic liquid, 1-butoxy-3-methylimidazolium, and butyl sulfonate.

2. The method for preparing a glucose sensor based on a composite thin film according to claim 1, characterized in that, The process of mixing MoS2 with an organic solvent and then subjecting it to ultrasonic disruption and centrifugation specifically includes the following steps: After mixing the MoS2 with the organic solvent, the mixture is subjected to a first ultrasonic disruption and a first centrifugation process to obtain a first precipitate. The first precipitate was mixed with the organic solvent and then subjected to a second ultrasonic crushing and a second centrifugation process.

3. The method for preparing a glucose sensor based on a composite thin film according to claim 1, characterized in that, The temperature for ultrasonic fragmentation is 0-4℃.

4. The method for preparing a glucose sensor based on a composite thin film according to claim 1, characterized in that, The annealing and drying process is carried out at a temperature of 45-60℃ for 1-2 hours.

5. The method for preparing a glucose sensor based on a composite thin film according to claim 1, characterized in that, The mass ratio of the polymer crosslinking agent, the ionic liquid, and the acetone is 1:(4-5):(6-8).

6. The method for preparing a glucose sensor based on a composite thin film according to claim 1, characterized in that, The drying process is carried out at a temperature of 65-75℃ for 22-26 hours.

7. The method for preparing a glucose sensor based on a composite thin film according to claim 1, characterized in that, The step of modifying the ion gel film sequentially with glucose oxidase and perfluorosulfonic acid-polytetrafluoroethylene copolymer specifically includes: The glucose oxidase was activated to obtain an activated glucose oxidase solution. The activated glucose oxidase solution was coated onto the ion gel film, and after incubation, the modification of the ion gel film by glucose oxidase was completed. The perfluorosulfonic acid-polytetrafluoroethylene copolymer was coated onto an ion gel film modified with glucose oxidase, and after drying, the modification of the ion gel film by the perfluorosulfonic acid-polytetrafluoroethylene copolymer was completed.

8. The method for preparing a glucose sensor based on a composite thin film according to claim 7, characterized in that, The concentration of glucose oxidase is 50-70 mg / mL.

9. A glucose sensor based on a composite thin film, characterized in that, The glucose sensor based on a composite thin film was prepared using the method described in any one of claims 1-8.

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