A zinc-air battery assisted enhanced self-powered electrochemical sensor and a preparation method and application thereof

Abstract

The application belongs to the technical field of electrochemical detection and analysis, and particularly relates to a zinc-air battery auxiliary enhanced self-powered electrochemical sensor and a preparation method and application thereof. A layer of WO3 film is grown on FTO through a hydrothermal method, a zinc sheet is used as an anode, the WO3 film is used as a cathode, then a microcystin-RR (MC-RR) aptamer is modified on the electrode to construct an electrochemical self-powered sensor, and the zinc-air battery is combined into the self-powered sensor, so that the output voltage can be obviously improved. The application widens the application of the WO3 film in the zinc-air battery, and the prepared sensor has a wide detection range, high sensitivity and low detection limit, and has important significance for the detection of MC-RR.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical detection and analysis technology, and specifically relates to a self-powered electrochemical sensor enhanced by a zinc-air battery and its preparation method, as well as the application of the self-powered electrochemical sensor in the detection of microcystin-RR. Background Technology

[0002] Eutrophication of water bodies, rising atmospheric carbon dioxide levels, and climate change are significant sources of bioactive cyanobacterial toxins. Microcystins (MCs) are a class of bioactive cyclic heptacapeptide compounds, the most widely distributed hepatotoxins, primarily produced by the freshwater algae *Microcystis aeruginosa*. Microcystins are heptacapeptide monocyclic hepatotoxins with a cyclic structure and spacer double bonds, thus exhibiting considerable stability. They strongly inhibit protein phosphatase activity, posing an increasing threat to ecology and human health. With the promulgation of the Chinese Drinking Water Standard (GB5749-2006), which limits the concentration of microcystins in drinking water to 1 μg / L, the implementation of this standard has placed higher demands on water quality. [5] Therefore, it is necessary to develop a highly sensitive method for detecting microcystin.

[0003] Currently, significant progress has been made in analytical methods for the detection and quantification of macromolecules (MCs). The main methods studied include the Protein Phosphatases Inhibition Assay (PPIA), Enzyme-Linked Immunosorbent Assay (ELISA), High Performance Liquid Chromatography (HPLC), and Liquid Chromatography-Mass Spectrometry (LC-MS). However, these methods have drawbacks such as high cost, cumbersome operation, or high instrument requirements.

[0004] Self-powered electrochemical sensors, as an emerging and powerful analytical method, have recently attracted much attention due to their advantages such as high sensitivity, low detection limit (LOD), no need for external power supply, and simple structure that facilitates miniaturization and integration. However, most self-powered sensors suffer from drawbacks such as low output voltage, low output power, and large micro-amplification current, requiring more complex and expensive instruments for detection, thus limiting the development of self-powered sensors.

[0005] Metal-air batteries generate electricity through a redox reaction between a metal anode and oxygen. Among them, zinc-air batteries have attracted increasing attention due to their advantages such as high energy density, use of ambient oxygen as fuel, low cost, and environmental friendliness. For example, Chinese patent CN116148322A discloses a photo-assisted zinc-air battery-based self-powered sensor for gallic acid detection, using zinc sheet as the anode and AgBr / CuBi2O4 as the cathode. WO3 thin films are widely used in various fields such as photocatalysis, electrochromism, photochromism, and gas sensing, but research in the field of electrochemical detection is relatively limited. Summary of the Invention

[0006] This invention develops a novel self-powered sensor by assembling a Zn sheet and a WO3 thin-film cathode. The nanoporous structure of the WO3 thin film provides a large specific surface area, enabling signal amplification and significantly improving the sensor's sensitivity. After coupling with an MC-RR aptamer, the target can be specifically captured on the electrode, increasing steric hindrance and thus achieving sensitive detection of MC-RR signals.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A method for fabricating a zinc-air battery-assisted enhanced self-powered electrochemical sensor, using WO3 thin film as the substrate material, and co-modifying it with a specific recognition element aptamer on the conductive surface of fluorine-doped tin oxide conductive glass (FTO), the specific steps of which are as follows:

[0009] (1) Preparation of WO3 seed layer: Concentrated hydrochloric acid was added dropwise to sodium tungstate solution under stirring to generate a light yellow precipitate; the precipitate was collected by centrifugation and washed until neutral; the product was dissolved in H2O2 to obtain a transparent sol; the transparent sol was spin-coated onto the cleaned FTO conductive glass, dried at 70℃ for 3 min, heated to 400℃ at a heating rate of 2℃ / min and held for 1 h, and then taken out after natural cooling to obtain FTO conductive glass containing WO3 seed layer.

[0010] The sodium tungstate solution has a molar concentration of 0.2–0.3 mol / L, the concentrated hydrochloric acid has a molar concentration of 12 mol / L, and the molar ratio of sodium tungstate to concentrated hydrochloric acid is 1:9–10. The tungstic acid in the transparent sol has a molar concentration of 0.6 mol / L; the spin-coating amount of the transparent sol is 200 μL / cm. 2 .

[0011] (2) Preparation of WO3 thin film

[0012] Under stirring, concentrated hydrochloric acid was added to the sodium tungstate solution to generate a pale yellow precipitate; the precipitate was collected by centrifugation and washed until neutral; the product was dissolved with hydrogen peroxide and diluted with deionized water to obtain a tungstic acid solution; the tungstic acid solution, ethylene glycol, hydrochloric acid, and deionized water were mixed evenly in a volume ratio of 3:9:1:3; the FTO conductive glass containing the WO3 seed layer obtained in step (1) was immersed face down into the mixed solution, kept warm in an oven at 120°C for 2 hours, and naturally cooled to room temperature. The FTO conductive glass was taken out and washed with deionized water and anhydrous ethanol in sequence, and then naturally dried at room temperature to obtain the electrode WO3 / FTO containing the WO3 thin film layer.

[0013] The sodium tungstate solution has a molar concentration of 0.2–0.3 mol / L, the concentrated hydrochloric acid has a molar concentration of 12 mol / L, and the molar ratio of sodium tungstate to concentrated hydrochloric acid is 1:9–10. The tungstic acid solution has a molar concentration of 0.1 mol / L, and the hydrochloric acid solution has a molar concentration of 3 mol / L.

[0014] (3) Fabrication of a self-powered electrochemical sensor enhanced by zinc-air battery assistance:

[0015] The MC-RR aptamer solution was drop-coated onto the surface of WO3 / FTO and dried overnight at room temperature to obtain apta / WO3 / FTO. Apta / WO3 / FTO was used as the cathode, a Zn sheet as the anode, and assembled with a single-chamber quartz electrolytic cell to form a self-powered sensor.

[0016] The molar concentration of the MC-RR aptamer solution is 1–3 μmol / L, preferably 1.5–2.5 μmol / L. The drop volume of the MC-RR aptamer solution is 20 μL / cm. 2 .

[0017] The nucleotide sequence of the MC-RR aptamer is: 5'-CAG CTCAGAAGC TTGATC CTA CTG CCC TTC AATGTT CAC TCC TGT TTC CTG ATC TTT GTC GAC TCG AAG TCG TGCATC TG-3'.

[0018] The application of the aforementioned zinc-air cell-assisted enhanced self-powered electrochemical sensor in the detection of MC-RR involves the following specific detection steps:

[0019] S1. Prepare MC-RR standard solution;

[0020] Accurately weigh a certain mass of MC-RR and prepare a solution of 1.0 × 10⁻⁶ ppm using deionized water. -4A standard solution of mol / L was prepared by serially diluting the standard solution with deionized water to obtain a series of MC-RR standard solutions of different concentrations, ranging from 1.0 × 10⁻⁶. -14 mol / L~1.0×10 -9 mol / L;

[0021] S2. Plotting the standard curve:

[0022] A series of known concentrations of MC-RR were drop-coated onto the surface of the prepared cathode material and incubated at room temperature for 10–50 min. Using a Zn sheet as the anode and a WO3 film as the cathode, MC-RR aptamers were assembled. Using 0.1 M PBS buffer solution as the electrolyte, the power density response was measured at a test potential of 0 V. A series of concentration-power density correspondences were obtained, and a standard curve of MC-RR was obtained. A linear relationship between the power density intensity after the addition of MC-RR and the logarithm of the MC-RR concentration was established, and the corresponding linear regression equation was obtained.

[0023] S3. Sample detection: The sample is filtered to remove impurities. The test is carried out according to step S2 above to obtain the electric power density value. The obtained electric power density is calculated using the linear regression equation obtained in step S2 to obtain the concentration of MC-RR in the sample.

[0024] The beneficial effects of this invention are:

[0025] This invention develops a novel self-powered sensor by assembling a Zn sheet anode and a WO3 thin-film cathode, and establishes an electrochemical detection method for MC-RR. Its features and advantages are described below:

[0026] (1) This invention constructs a novel self-powered sensor by assembling a Zn sheet anode and a WO3 thin film cathode. The nanoporous structure of the WO3 thin film can provide a large specific surface area, enabling signal amplification and significantly improving the sensor's sensitivity. After coupling with the MC-RR aptamer, the target can be specifically captured on the electrode, increasing the steric hindrance, thereby achieving sensitive detection of MCRR.

[0027] (2) Compared with traditional detection methods, the electrochemical detection method proposed in this invention has the advantages of simple and flexible operation, simple instruments and equipment, high sensitivity, wide linear range, low detection limit and low detection cost. Attached image description:

[0028] The invention will be further described below with reference to the accompanying drawings and examples.

[0029] Figure 1 This is a diagram illustrating the working mode of a self-powered sensor composed of a cathode MC-RR / apta / WO3 / FTO and an anode Zn sheet.

[0030] Figure 2 These are scanning electron microscope images of WO3 thin films at different magnifications;

[0031] Figure 3 The effect of PBS solutions with different pH values ​​on the maximum power density of the sensor;

[0032] Figure 4 This is a comparison graph showing the changes in electric power density before and after drop-coating 20 μL of aptamers with concentrations of (a) 1 μM, (b) 1.5 μM, (c) 2 μM, (d) 2.5 μM, and (e) 3 μM.

[0033] Figure 5 This is a comparison graph of the changes in electrical power density of MC-RR under different incubation times;

[0034] Figure 6 These are the power density curves during the fabrication of aptamer sensors using WO3 / FTO, apta / WO3 / FTO, and MC-RR / apta / WO3 / FTO.

[0035] Figure 7 This is a short-circuit current graph for MC-RR at different concentrations. The concentrations of MC-RR, arranged from lowest to highest peak value, are 1×10⁻⁶. -14 mol / L, 1×10 -14 mol / L, 1×10 -13 mol / L, 1×10 -12 mol / L, 1×10 -11 mol / L, 1×10 -10 mol / L, 1×10 -9 mol / L;

[0036] Figure 8 It is a standard curve of the maximum electric power density after adding MC-RR versus the logarithm of MC-RR concentration. Detailed Implementation

[0037] The invention will be described in more detail below with reference to embodiments.

[0038] Example 1

[0039] The specific steps for preparing the WO3 thin film cathode are as follows:

[0040] (1) Preparation of WO3 seed layer:

[0041] Weigh 4g of sodium tungstate hydrate using a balance and dissolve it in 50mL of water to obtain a 0.24M sodium tungstate solution. Under magnetic stirring, add 12M concentrated hydrochloric acid dropwise until no more pale yellow precipitate forms. The total amount of concentrated hydrochloric acid added is 10mL. Then, transfer the resulting pale yellow precipitate into centrifuge tubes and centrifuge at 7000 rpm for 5 minutes. Repeat this process 5-7 times until the pH of the centrifuged solution is approximately 7. Afterward, dissolve the washed pale yellow precipitate in 20mL of H₂O₂ to obtain a transparent sol, which is then refrigerated for later use.

[0042] 200 μL of transparent sol was spin-coated onto the cleaned FTO conductive glass and dried in an oven at 70 °C for 3 min. Then, it was placed in a box-type muffle furnace for sintering treatment, heated to 400 °C at a heating rate of 2 °C / min and held at that temperature for 1 h. After the conductive glass cooled naturally, it was removed to obtain the WO3 seed layer.

[0043] (2) Preparation of WO3 thin films:

[0044] Weigh 6.6009 g of sodium tungstate using a balance and dissolve it in 75 mL of water. Add 15 mL of concentrated hydrochloric acid (12 M) while stirring to obtain a pale yellow precipitate, which is then centrifuged. Dissolve the precipitate in 60 mL of hydrogen peroxide and stir until completely dissolved. Dilute the solution to 200 mL with deionized water to obtain a 0.1 M tungstic acid solution. Add 12 mL of 0.1 M tungstic acid solution, 36 mL of ethylene glycol, 4 mL of 3 M HCl, and 12 mL of deionized water to an 80 mL PTFE high-pressure reactor liner and mix thoroughly. Immerse the conductive side of an FTO conductive glass coated with a seed layer into the mixture and heat at 120 °C for 2 hours. After naturally cooling to room temperature, remove the FTO conductive glass and wash it successively with deionized water and anhydrous ethanol, then air dry at room temperature.

[0045] Figure 2 These are scanning electron microscope (SEM) images of WO3 thin films at different magnifications; from Figure 2 It is evident that the WO3 film is composed of intricately connected nano-branches. Due to the irregular arrangement of the nano-branches, a nanoporous structure is formed. This structure can provide the WO3 film with a large specific surface area, which is conducive to loading more biometric elements and thus enhancing detection performance.

[0046] Example 2

[0047] The WO3 thin film was prepared in the same manner as in Example 1. A zinc-air battery self-powered system was prepared using a zinc sheet as the anode and a WO3 thin film as the cathode. The zinc-air battery self-powered system was placed in a buffer solution containing 0.1 mol / L PBS with a pH of 5–7, using the PBS buffer solution as the electrolyte. The effect of different pH values ​​of the PBS solution on the maximum power density of the sensor was investigated, and the results are shown in [Figure 1]. Figure 3 .from Figure 3 It can be seen that the power density of the sensor is relatively high when the PBS buffer solution is acidic; the power density of the sensor is highest at pH 7.

[0048] Example 3

[0049] The WO3 thin film was prepared in the same manner as in Example 1. 20 μL of MC-RR aptamer solution was drop-coated onto the surface of the WO3 / FTO cathode and dried overnight at room temperature; the concentrations of the MC-RR aptamer solution were 1 μM, 1.5 μM, 2 μM, 2.5 μM, and 3 μM, respectively. A self-powered sensor was assembled from the apta / WO3 / FTO cathode, the Zn anode, and a single-chamber quartz electrolytic cell. The change in power density after drop-coating different concentrations of MC-RR aptamer was observed. The results are shown in […]. Figure 4 .from Figure 4 It can be seen that when the aptamer concentration increases from 1 μmol / L to 1.5 μmol / L, ΔP max The value gradually decreases, and as the aptamer concentration further increases, ΔP... max The value tends to stabilize. Therefore, the optimal aptamer concentration is 1.5 μmol / L.

[0050] Example 4

[0051] The preparation of the WO3 film was the same as in Example 1. 20 μL of a 2 μM MC-RR aptamer solution was drop-coated onto the surface of the WO3 / FTO cathode and dried overnight at room temperature to obtain apta / WO3 / FTO. To prepare the MC-RR solution, a certain mass of MC-RR was accurately weighed and dissolved in deionized water to prepare a 1×10⁻⁶ solution. -10 A mol / L MC-RR solution was prepared by dropping 20 μL of the solution onto the surface of an apta / WO3 / FTO electrode and incubating for 10–50 min. A self-powered system was constructed using MC-RR / apta / WO3 / FTO as the cathode and a zinc sheet as the anode. The changes in power density after different incubation times were observed. The results are shown in [Figure missing]. Figure 5 .from Figure 5 It can be seen that within the range of 10-20 min, ΔP increases with increasing incubation time. maxThe value increases significantly, then reaches a maximum. When the incubation time exceeds 20 min, the power density begins to gradually decrease and tends to stabilize. Therefore, 20 min is the most suitable detection binding time for this experiment.

[0052] Figure 6 It is WO3 / FTO, apta / WO3 / FTO and MC-RR 20 The power density curve during the fabrication of the aptamer sensor using / apta / WO3 / FTO.

[0053] Example 5

[0054] like Figure 1 As shown, a self-powered electrochemical sensor enhanced by zinc-air battery is prepared by using a zinc sheet as the anode and a WO3 thin film as the cathode to form a self-powered system for MC-RR detection.

[0055] A method for preparing a zinc-air cell-assisted enhanced self-powered electrochemical sensor comprises the following steps:

[0056] (1) Preparation of WO3 seed layer:

[0057] Weigh 4g of sodium tungstate hydrate using a balance and dissolve it in 50mL of water to obtain a 0.24M sodium tungstate solution. Under magnetic stirring, add 12M concentrated hydrochloric acid dropwise until no more pale yellow precipitate forms. The total amount of concentrated hydrochloric acid added is 10mL. Then, transfer the resulting pale yellow precipitate into centrifuge tubes and centrifuge at 7000 rpm for 5 minutes. Repeat this process 5-7 times until the pH of the centrifuged solution is approximately 7. Afterward, dissolve the washed pale yellow precipitate in 20mL of H₂O₂ to obtain a transparent sol, which is then refrigerated for later use.

[0058] 200 μL of transparent sol was spin-coated onto the cleaned FTO conductive glass and dried in an oven at 70 °C for 3 min. Then, it was placed in a box-type muffle furnace for sintering treatment, heated to 400 °C at a heating rate of 2 °C / min and held at that temperature for 1 h. After the conductive glass cooled naturally, it was removed to obtain the WO3 seed layer.

[0059] (2) Preparation of WO3 thin films:

[0060] 6.6009 g of sodium tungstate was weighed using a balance and dissolved in 75 mL of water. 15 mL of concentrated hydrochloric acid (12 M) was added while stirring, resulting in a pale yellow precipitate, which was then centrifuged. The precipitate was dissolved in 60 mL of hydrogen peroxide and stirred until completely dissolved. The solution was then diluted with deionized water to 200 mL to obtain a 0.1 M tungstic acid solution. In an 80 mL polytetrafluoroethylene high-pressure reactor liner, 12 mL of 0.1 M tungstic acid solution, 36 mL of ethylene glycol, 4 mL of 3 M HCl, and 12 mL of deionized water were added and mixed thoroughly. Then, an FTO conductive glass coated with a seed layer was immersed, conductive side down, into the mixture and kept at 120 °C for 2 hours. After naturally cooling to room temperature, the FTO conductive glass was removed and washed successively with deionized water and anhydrous ethanol, then air-dried at room temperature to obtain WO3 / FTO.

[0061] (3) Fabrication of a self-powered electrochemical sensor enhanced by zinc-air battery assistance:

[0062] 20 μL of a 1.5 μM MC-RR aptamer solution was drop-coated onto the surface of a WO3 / FTO cathode and dried overnight at room temperature to prepare apta / WO3 / FTO. Finally, the apta / WO3 / FTO cathode, the Zn anode, and the single-chamber quartz electrolytic cell were assembled into a self-powered sensor.

[0063] (4) Plotting the standard curve:

[0064] To prepare an MC-RR solution, accurately weigh a certain mass of MC-RR and use deionized water to prepare a 1.0 × 10⁻⁶ solution. -4 A series of MC-RR standard solutions of different concentrations were obtained by serially diluting the standard solutions with deionized water. 20 μL of the MC-RR standard solutions of different concentrations were dropped onto the surface of the apta / WO3 / FTO electrode and incubated for 20 min to prepare MC-RR / apta / WO3 / FTO.

[0065] A self-powered electrochemical sensor based on a zinc-air cell-assisted enhancement was constructed using MC-RR / apta / WO3 / FTO as the cathode and a zinc sheet as the anode for MC-RR detection. The power density of the zinc-air cell self-powered system was measured in a 0.1 mol / L PBS buffer solution at pH 7. Short-circuit current diagrams for different concentrations of MC-RR are shown below. Figure 7 As shown, the concentrations of MC-RR, arranged from lowest to highest peak value, are: 1×10⁻⁶ -14 mol / L, 1×10 -13 mol / L, 1×10 -12 mol / L, 1×10 -11 mol / L, 1×10-10 mol / L, 1×10 -9 mol / L; then establish a linear relationship between the power density after adding MC-RR and the logarithm of the MC-RR concentration (mol / L); Figure 8 The corresponding linear regression equation is: ΔP = 47.368 + 2.313log[C] MC-RR [nM], the correlation coefficient (R) was 0.983; the detection range of the linear regression equation was 1×10⁻⁶. -14 mol / L to 1×10 -9 mol / L, the limit of detection is 1.31 × 10⁻⁶. -15 mol / L.

[0066] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A self-powered electrochemical sensor enhanced by a zinc-air battery, characterized in that, The sensor comprises an apta / WO3 / FTO cathode made by modifying the conductive surface of fluorine-doped tin oxide conductive glass with WO3 thin film as the substrate material and a specific recognition element aptamer, a Zn sheet as the anode, and a single-chamber quartz electrolytic cell; the specific recognition element aptamer is an MC-RR aptamer. The preparation method of the apta / WO3 / FTO includes the following steps: (1) Under stirring, concentrated hydrochloric acid was added dropwise to sodium tungstate solution to generate a pale yellow precipitate. The precipitate was collected by centrifugation and washed until neutral. The product was dissolved in H2O2 to obtain a transparent sol. The transparent sol was spin-coated onto the cleaned FTO conductive glass, dried at 70℃ for 3 min, heated to 400℃ at a heating rate of 2℃ / min and kept at that temperature for 1 h. After natural cooling, it was taken out to obtain FTO conductive glass containing WO3 seed layer. (2) Mix tungstic acid solution, ethylene glycol, hydrochloric acid and deionized water evenly to obtain a mixed solution; Immerse the WO3 seed layer of the FTO conductive glass containing the WO3 seed layer obtained in step (1) downward into the mixed solution, keep it at 120℃ for 2 hours, cool it naturally to room temperature, take it out, clean it, and air dry it naturally at room temperature to obtain WO3 / FTO. (3) The MC-RR aptamer solution was drop-coated onto the WO3 / FTO surface and dried at room temperature to obtain apta / WO3 / FTO.

2. A method for preparing a self-powered electrochemical sensor enhanced by a zinc-air battery as described in claim 1, characterized in that, Specifically, the steps include the following: (1) Preparation of WO3 seed layer: Concentrated hydrochloric acid was added dropwise to sodium tungstate solution under stirring to generate a pale yellow precipitate; Centrifuge to collect the precipitate, and wash until neutral. The product was dissolved in H2O2 to obtain a transparent sol; the transparent sol was spin-coated onto the cleaned FTO conductive glass, dried at 70℃ for 3 min, heated to 400℃ at a heating rate of 2℃ / min and held for 1 h, and then removed after natural cooling to obtain FTO conductive glass containing a WO3 seed layer. (2) Preparation of WO3 film: Concentrated hydrochloric acid was added to sodium tungstate solution under stirring to form a pale yellow precipitate; the precipitate was collected by centrifugation and washed until neutral; The product was dissolved in hydrogen peroxide and then diluted with deionized water to obtain a tungstic acid solution. The tungstic acid solution, ethylene glycol, hydrochloric acid and deionized water were mixed evenly in a volume ratio of 3:9:1:3 to obtain a mixed solution. The WO3 seed layer of the FTO conductive glass containing the WO3 seed layer obtained in step (1) was immersed downward into the mixed solution and kept in an oven at 120°C for 2 hours. After naturally cooling to room temperature, the FTO conductive glass was taken out and washed with deionized water and anhydrous ethanol in sequence. It was then air-dried at room temperature to obtain WO3 / FTO. (3) Preparation of a self-powered electrochemical sensor enhanced by zinc-air battery: The MC-RR aptamer solution was drop-coated onto the surface of WO3 / FTO and dried at room temperature to form apta / WO3 / FTO; apta / WO3 / FTO was used as the cathode, Zn sheet was used as the anode, and assembled with a single-chamber quartz electrolytic cell to form a self-powered sensor.

3. The method for preparing the zinc-air battery-assisted enhanced self-powered electrochemical sensor according to claim 2, characterized in that, In step (1), the molar concentration of sodium tungstate solution is 0.2~0.3 mol / L, the molar concentration of concentrated hydrochloric acid is 12 mol / L, and the molar ratio of sodium tungstate to concentrated hydrochloric acid is 1:9~10; the molar concentration of tungstic acid in the transparent sol is 0.6 mol / L; and the spin-coating amount of the transparent sol is 200 μL / cm. 2 .

4. The method for preparing the zinc-air battery-assisted enhanced self-powered electrochemical sensor according to claim 2, characterized in that, In step (2), the molar concentration of sodium tungstate solution is 0.2~0.3 mol / L, the molar concentration of concentrated hydrochloric acid is 12 mol / L, and the molar ratio of sodium tungstate to concentrated hydrochloric acid is 1:9~10; the molar concentration of tungstic acid solution is 0.1 mol / L; and the molar concentration of hydrochloric acid is 3 mol / L.

5. The method for preparing the zinc-air battery-assisted enhanced self-powered electrochemical sensor according to claim 2, characterized in that, In step (3), the molar concentration of the MC-RR aptamer solution is 1~3 μmol / L; the drop volume of the MC-RR aptamer solution is 20 μL / cm. 2 .

6. The method for preparing the zinc-air battery-assisted enhanced self-powered electrochemical sensor according to claim 2, characterized in that, The nucleotide sequence of the MC-RR aptamer is: 5'-CAG CTC AGA AGC TTG ATC CTA CTG CCC TTCAAT GTT CAC TCC TGT TTC CTG ATC TTT GTC GAC TCG AAG TCG TGC ATC TG-3'.

7. The application of a zinc-air battery-assisted enhanced self-powered electrochemical sensor as described in claim 1 in the detection of MC-RR.

8. The application according to claim 7, characterized in that, Using PBS buffer solution as the electrolyte, the electrical power density of the test solution before and after binding to the aptamer was tested at a test potential of 0 V. The concentration of MC-RR in the test solution was calculated according to the standard curve method.

9. The application according to claim 8, characterized in that, The PBS buffer solution had a molar concentration of 0.1 mol / L and a pH of 5–7; the binding time between the detection solution and the aptamer was 10–50 min.

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