Enzyme-like biological fuel cell as well as preparation method and application thereof

Abstract

The invention discloses an enzyme-like biological fuel cell and a preparation method and application thereof, the enzyme-like biological fuel cell comprises an anode, a cathode and an electrolyte, the anode is a CC-coated FeCo PBNCs anode, the cathode is CC-coated NiMn PBNCs-coated AuNPs, and the electrolyte comprises glucose, hydrogen peroxide, methylene blue and a PBS buffer solution. The enzyme-like biological fuel cell is applied to construction of a self-powered sensor for quantitative analysis of a target analyte, and the influence of the environment on the energy supply efficiency can be reduced, so that the self-powered detection stability is improved. According to the invention, the problem of low enzymatic activity of an enzyme biological fuel cell is solved, and verification is made by taking construction of a patulin aptamer sensor as an example. The enzyme-like biological fuel cell plays a role of a biological enzyme by using a non-biological material, so that the effect influenced by the environment is reduced, the cost is low, and the construction of a self-energized sensor is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of biofuel cells, and particularly relates to a mimetic enzyme biofuel cell, a preparation method thereof, and an application thereof. Background Art

[0002] An enzymatic biofuel cell (EBFC) is a device that uses enzymes as catalysts to directly convert the chemical energy of renewable biomass fuels such as glucose, ethanol, hydrogen, etc. into electrical energy. The core advantages of this type of battery lie in its environmental friendliness, high energy conversion efficiency, and wide range of fuel sources. The working principle of an enzymatic biofuel cell is the same as that of all fuel cells, that is, using a catalyst to separate electrons from the parent molecule and forcing them to bypass the electrolyte barrier through a wire to generate an electric current. Due to its characteristics of operating at room temperature and neutral pH, the enzymatic biofuel cell is widely used in fields such as power sources for implantable devices, wearable devices, self-powered sensors, and wastewater treatment. It can carry out oxidation-reduction reactions in a mild environment, so it is particularly suitable for use as an implantable or wearable EBFC in the biomedical field.

[0003] In recent years, researchers have made significant progress in the electrode construction and application of enzymatic biofuel cells. However, as a biological catalyst, enzymes may lose their activity under changes in operating conditions (such as temperature, pH value) or during long-term operation, which affects the long-term stability and service life of the battery. Due to the relatively large size of enzymes, their mass transfer efficiency on the electrode surface may be low, which limits the current density and power output of the battery. Although enzymes are relatively easy to produce on a large scale, compared with mature metal catalysts, the production and purification processes of enzymes may be costly, especially in cases where high-purity and high-activity enzymes are required. Enzymes have high requirements for fuel purity, and impurities in the fuel may inhibit the activity of enzymes, which limits the application of EBFCs in the treatment of complex or unpurified fuels. The power density and energy density of enzymatic biofuel cells are generally lower than those of traditional fuel cells, which limits their use in applications that require high energy output. Enzymes are very sensitive to environmental conditions (such as temperature, humidity), which requires the battery to be operated in a strictly controlled environment, increasing the operational complexity and cost. Although EBFCs have good biocompatibility, in actual biomedical applications, such as implantable devices, enzymes and electrode materials may require further biocompatibility evaluation and improvement. The preparation of enzymatic biofuel cells involves complex biochemistry and materials science technologies, which increases the technical threshold and R & D difficulty. The large-scale production of enzymatic biofuel cells may face challenges, including maintaining enzyme activity, controlling production costs, and ensuring the consistency of product quality. Although EBFCs use renewable fuels and biological catalysts, their production, use, and waste treatment processes may have an impact on the environment, and life cycle assessment and environmental impact assessment are required.

[0004] The information disclosed in this background art section is only intended to enhance the general understanding of the background of the present invention and should not be regarded as an admission or any form of implication that this information constitutes prior art already known to those of ordinary skill in the art. Summary of the Invention

[0005] An object of the present invention is to provide a mimetic enzyme biofuel cell and a preparation method thereof, so as to overcome the disadvantages of high stability, weak environmental interference, high reaction activity, low cost, etc. for the operation of fuel cells.

[0006] Another object of the present invention is the application of the mimetic enzyme biofuel cell in a patulin aptamer self-powered sensor.

[0007] To achieve the above object, the present invention provides a mimetic enzyme biofuel cell, which includes an anode, a cathode and an electrolyte. The anode is a CC@FeCo PBNCs anode, the cathode is a CC@NiMn PBNCs@AuNPs, and the electrolyte includes glucose, hydrogen peroxide, methylene blue, and PBS buffer solution.

[0008] A preparation method of a mimetic enzyme biofuel cell, the fuel cell constructs an electrochemical / colorimetric dual-mode sensor cathode and anode based on FeCo-based Prussian blue analogues (FeCo PBNCs) with mimetic biocatalytic activity, carbon cloth (CC), NiMn-based Prussian blue analogues (NiMn PBNCs), and gold nanoparticles (AuNPs).

[0009] Preferably, in the above technical solution, the preparation of the anode includes taking 30 - 50 μL of 1 - 10 mg / mL FeCoPBNCs and drop-coating it on the surface of the carbon cloth electrode, followed by drying to obtain the anode.

[0010] Preferably, in the above technical solution, the preparation of the FeCo PBNCs includes: adding 0.1 - 10 g of Co(OH) 2 to a 0.005 - 0.1 mol / L K 3 [Fe(CN) 6 solution, stirring for 1 - 10 h, then standing for 8 - 24 h, centrifuging, washing, and freeze-drying to obtain FeCo PBNCs.

[0011] Preferably, in the above technical solution, the preparation of the cathode includes: drop-coating 30 - 50 μL of NiMn PBNCs on the surface of the carbon cloth electrode, drying, and then dropping 30 - 40 μL of 0.01% AuNPs solution and incubating at 35 - 40 °C for 4 - 8 h to obtain the cathode.

[0012] Preferably, in the above technical solution, the preparation of the NiMn PBNCs includes: mixing NiCl 2 and citric acid to form aqueous solution A, and mixing it with an equal volume of aqueous solution B which is a mixture of MnCl 2 and citric acid. Then mix aqueous solution A and aqueous solution B with aqueous solution C which is a mixture of K 4 Fe(CN) 6 and excessive KCl. Stir and age the reaction at room temperature, centrifuge to separate the particles, wash and dry to obtain NiMnPBNCs.

[0013] Preferably, in the above technical solution, add 50 - 100 mL of aqueous solution A which is a mixture of 0.8 - 1.4 mmol of NiCl 2 and 1.6 - 2.2 mmol of citric acid to an equal volume of aqueous solution B which is a mixture of 0.8 - 1.4 mmol of MnCl 2 and 1.6 - 2.2 mmol of citric acid. Then pour the mixed solution of A and B into aqueous solution C which is a mixture of 0.94 - 1.56 mmol of K 4 Fe(CN) 6 and 1.5 - 2.2 g of excessive KCl. Stir the solution and age it at room temperature for 12 - 24 h. Centrifuge to separate the particles, wash with water, and vacuum freeze-dry for 8 - 12 h to obtain NiMn PBNCs.

[0014] An application of the above enzyme-like biofuel cell, where the enzyme-like biofuel cell is used to construct a self-powered sensor.

[0015] A method for using the enzyme-like biofuel cell to construct a self-powered sensor, the method includes the following steps:

[0016] (1) Use the cathode primer bio-probe of the enzyme-like biofuel cell to specifically recognize the analyte to construct a self-powered sensor;

[0017] (2) After adding the monitoring substance, measure the instantaneous current of the self-powered sensor containing different concentrations of the analyte.

[0018] A method for using the enzyme-like biofuel cell to prepare a self-powered biosensor for patulin aptamer, including the following steps:

[0019] (1) Prepare the anode of the self-powered sensor for patulin aptamer: Drop the FeCo PBNCs solution onto the surface of the carbon cloth electrode, dry, and wash with water;

[0020] (2) Preparation of the cathode of the patulin aptamer self-powered sensor: Drop NiMn PBNCs onto carbon cloth, dry it, drop and incubate with AuNPs solution, immerse it in EDC / NHS solution, rinse with water, then drop and coat patulin aptamer on the carbon cloth, incubate, add MCH for reaction, and wash to remove excess MCH;

[0021] Among them, the nucleotide sequence of the patulin aptamer is: 5’-GGCCCGCCAACCCGCATCATCTACACTGATATTTTACCTT-3’.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) For the enzyme-mimicking biofuel cell of the present invention, the core of the design mainly focuses on the enzyme-mimicking active material. FeCo PBNCs with enzyme-mimicking activity are used to simulate the dual enzyme activities of peroxidase-mimicking enzyme and glucose oxidase-mimicking enzyme to catalytically decompose glucose and hydrogen peroxide in the electrolyte to generate electrons. The key to applying it to the patulin aptamer self-powered sensor lies in modifying the cathode with patulin aptamer to capture patulin, thereby changing the electrode potential of the cathode, causing a change in the electromotive force (ΔE) of the enzyme-mimicking biofuel cell. The electrical signal value is negatively correlated with the concentration of patulin, and quantitative detection of patulin is achieved through electrochemical signal detection. The enzyme-mimicking biofuel cell designed by the present invention can be used to construct a self-powered sensor, which has the characteristics of high stability, weak environmental interference, high reaction activity, and low cost.

[0024] (2) The enzyme-mimicking biofuel cell of the present invention does not require a bio-enzyme catalyst and has a low cost; it does not require the catalytic action of non-biological materials to replace the bio-enzyme catalyst, has high catalytic stability, is less affected by the environment, and thus improves the anti-interference ability of the fuel cell. Applying it to a self-powered biosensor is beneficial to improving the stability of the sensor. Catalytic decomposition is carried out using the dual enzyme-mimicking activity characteristics, which has high sensitivity, selectivity, high catalytic activity, high conversion rate, and also has advantages such as low cost and simple operation; it is used to construct a self-powered sensor to reduce environmental pollution.

[0025] (3) Using the enzyme-mimicking biofuel cell of the present invention to construct a self-powered sensor for quantitative analysis of target analytes can reduce the impact of the environment on the power supply efficiency and thus improve the stability of self-powered detection. The present invention solves the problem of low enzyme activity of the enzyme biofuel cell and makes a verification taking the construction of a patulin aptamer sensor as an example. This enzyme-mimicking biofuel cell uses non-biological materials to play the role of bio-enzymes, is less affected by the environment, and has a low cost, which is conducive to the construction of self-powered sensors. Description of the Drawings

[0026] Figure 1Schematic diagram of the assembly process of the enzyme-like biofuel cell cathode and anode according to the present invention;

[0027] Figure 2 Schematic diagram of the device of the patulin aptamer self-powered biosensor according to the present invention;

[0028] Figure 3 Schematic diagram of the principle of the patulin aptamer self-powered biosensor for recognizing and detecting patulin according to the present invention;

[0029] Figure 4 Schematic diagram of the test current intensity of the patulin aptamer self-powered biosensor for testing the presence or absence of patulin by combining a multimeter and a mobile phone according to the present invention;

[0030] Figure 5 Schematic diagram of the chronopotentiometry test of the electrode of the enzyme-like biofuel cell according to the present invention;

[0031] Figure 6 Schematic diagram of the color reaction of FeCo PBNCs according to the present invention. Detailed implementation manners

[0032] The following will describe in detail the specific implementation manners of the present invention with reference to the accompanying drawings. It should be understood that the protection scope of the present invention is not limited by the specific implementation manners.

[0033] Unless otherwise clearly stated, throughout the specification and claims, the term "comprise" or its variations such as "comprises" or "including" etc. will be understood to include the stated elements or components, without excluding other elements or other components.

[0034] As Figures 1 to 6 shown, an enzyme-like biofuel cell according to a specific implementation manner of the present invention, the enzyme-like biofuel cell includes an anode, a cathode and an electrolyte. The anode is a CC@FeCo PBNCs anode, the cathode is CC@NiMn PBNCs@AuNPs, and the electrolyte includes glucose, hydrogen peroxide, methylene blue, and PBS buffer solution.

[0035] A preparation method of an enzyme-like biofuel cell, the fuel cell constructs an electrochemical / colorimetric dual-mode sensor cathode and anode based on FeCoPBNCs, CC, NiMn PBNCs and AuNPs with bio-enzyme-like activity.

[0036] A preparation method of an enzyme-like biofuel cell includes the following steps:

[0037] 1. Preparation of the CC@FeCo PBNCs anode

[0038] (1) Add 0.1 - 10 g of Co(OH) 2 to a 0.005 - 0.1 mol / L solution of K 3 [Fe(CN) 6 . Stir for 1 - 10 h, then let stand for 8 - 24 h. Centrifuge and wash with water multiple times, and freeze - dry to obtain FeCo PBNCs.

[0039] (2) Take 30 - 50 μL of 1 - 10 mg / mL FeCo PBNCs and drop - coat it on the surface of a carbon cloth electrode. Dry at 35 - 40 °C for 2 - 4 h to obtain the anode.

[0040] 2. Preparation of the CC@NiMn PBNCs@AuNPs cathode

[0041] (1) Preparation of NiMn PBNCs: Add 50 - 100 mL of aqueous solution A (0.8 - 1.4 mmol NiCl 2 and 1.6 - 2.2 mmol citric acid) drop - by - drop into an equal volume of aqueous solution B (0.8 - 1.4 mmol MnCl 2 and 1.6 - 2.2 mmol citric acid). Then, pour the mixed solution of A and B into another aqueous solution C (0.94 - 1.56 mmol of K 4 [Fe(CN) 6 and 1.5 - 2.2 g of excess KCl). Stir the solution vigorously at room temperature and age for about 12 - 24 h. Separate the particles by centrifuging at 10000 rpm for 10 min, then wash with deionized water and vacuum freeze - dry for 8 - 12 h.

[0042] (2) Preparation of AuNPs: Add 1 - 4 mL of 1% chloroauric acid solution to 99 - 200 mL of tetraoctylammonium bromide and stir evenly. Then add 1 - 4 mL of ice - cold 2% sodium borohydride solution and stir for 0.5 - 2 h to obtain an AuNPs solution.

[0043] (3) Assembly of the enzyme - like biofuel cell cathode: Drop - coat 30 - 50 μL of NiMn PBNCs on the surface of a carbon cloth electrode. After drying at 35 - 40 °C for 2 - 4 h, drop - add 30 - 40 μL of 0.01% AuNPs solution and incubate at 37 °C for 4 - 8 h to obtain the cathode. The assembly process is as Figure 1 .

[0044] 3. Preparation of the electrolyte and PBS buffer

[0045] (1) Add 15 - 20 mg of methylene blue and 1 - 6 mL of 1% H 2 O 2, 90 - 140 mg of glucose, ultrasonic treatment for 3 - 5 min to obtain an electrolyte solution.

[0046] (2) Weigh 0.3 - 2.0 g of anhydrous sodium phosphate and 1.4 - 3.0 g of sodium chloride, mix them in 250 - 400 mL of ultrapure water to obtain solution A; weigh 0.3 - 2.0 g of disodium hydrogen phosphate dihydrate and 1.4 - 3.0 g of sodium chloride, mix them in 250 - 400 mL of ultrapure water to obtain solution B. Use solution B to adjust the pH of solution A to 7.4 to obtain a PBS buffer solution.

[0047] The application of the enzyme - like bio - fuel cell is used to construct a self - powered sensor. The method for using the enzyme - like bio - fuel cell to construct a self - powered sensor includes the following steps:

[0048] (1) The cathode primer bioprobe of the enzyme - like bio - fuel cell specifically recognizes the analyte to construct a self - powered sensor;

[0049] (2) After adding the monitoring substance, measure the transient current of the self - powered sensor containing different concentrations of the analyte.

[0050] I. Application of the enzyme - like bio - fuel cell

[0051] In this example, an enzyme - like bio - fuel cell is used to prepare a self - powered biosensor for detecting patulin aptamer.

[0052] The preparation method includes the following steps:

[0053] 1. Preparation of FeCo PBNCs, NiMn PBNCs and AuNPs

[0054] (1) Preparation of FeCo PBNCs: Add 1 g of Co(OH) 2 to 40 mL of 0.0125 mol / L K 3 [Fe(CN) 6 solution, stir for 2 h and then let it stand for 8 h, centrifuge, wash with water multiple times, and freeze - dry to obtain FeCo PBNCs.

[0055] (2) Preparation of NiMn PBNCs: Add 50 mL of aqueous solution A (0.8 mmol NiCl 2 and 1.6 mmol citric acid) dropwise to an equal volume of aqueous solution B (0.8 mmol MnCl 2 and 1.6 mmol citric acid). Then, pour the mixed solution of A and B into K 4 Fe(CN) 6In another aqueous solution (C) of [[ID=]] (0.94 mmol) and excess KCl (1.5 g). The solution was vigorously stirred at room temperature and aged for about 24 h. The particles were separated by centrifugation at 10000 rpm for 10 min, then washed with deionized water and freeze-dried in vacuo for 12 h.

[0056] 2. Preparation of the anode of the patulin aptamer self-powered sensor

[0057] Take 40 μL of 5 mg / mL FeCo PBNCs solution and drop it on the surface of the carbon cloth electrode, dry it at 37 °C for 3 h, wash it with ultrapure water and store it at 4 °C, as Figure 2 shown.

[0058] 3. Preparation of the specific cathode of the patulin aptamer self-powered sensor

[0059] Drop 40 μL of 5 mg / mL NiMn PBNCs onto the carbon cloth, dry it at 37 °C for 3 h, add 30 μL of 0.01% AuNPs solution and incubate at 37 °C for 4 h, immerse it in 30 μL of 10 mg / mL EDC / NHS solution for 1 h, after rinsing with ultrapure water, drop 30 μL of patulin aptamer on the carbon cloth, incubate at 4 °C for 12 h, add 30 μL of 1 mM MCH and react for 0.5 h, wash to remove the excess MCH, as Figure 2 shown.

[0060] Recognition of the patulin aptamer sensor cathode: Drop 10 μL of the test solution onto the surface of the modified specific cathode electrode of the self-powered sensor, incubate at 37 °C for 2 h, wash with ultrapure water to obtain the biosensor, and store it at 4 °C for standby.

[0061] The supporting electrolyte of the above-mentioned constructed enzyme-like biofuel cell and self-powered sensor is 0.01 M PBS buffer solution (pH = 7.4) containing 0.5 mM methylene blue, 0.01% H 2 O 2 and 5 mM glucose, and the measuring device is as Figure 2 shown.

[0062] The principle of detecting patulin by the patulin aptamer self-powered sensor is as Figure 3 shown:

[0063] When patulin is absent, the electrode potential of the cathode is E 2 (V), the anode potential E 1 (V), and it can be known from this that the electromotive force ΔE 0 of the self-powered sensor without patulin is E 2 - E 1; When patulin is present, patulin is captured by the aptamer, causing the electrode potential of the cathode to change to E 3 (V), the anode potential E 1 (V), and at this time, the electromotive force ΔE 1 = E 3 - E 1 . Patulin exists in the cathode electrode, increasing the steric hindrance of the cathode, hindering the transfer of electrons, and reducing the electrode potential of the cathode. Therefore, E 2 > E 3 , ΔE 0 > ΔE 1 . So, when patulin is captured, its instantaneous current value will decrease, as shown in Figure 4 . The instantaneous current value is negatively correlated with the patulin concentration, thus realizing the quantitative detection of patulin. The patulin content is obtained through the corresponding relationship between the decrease value of the instantaneous current and the target patulin.

[0064] II. Electrochemical Characterization of the Patulin Aptamer Self-Powered Sensor

[0065] To verify the detection activity of the sensor, the sensor was tested by combining a multimeter with a mobile phone. As shown in Figure 4 , when the target was not introduced into the sensor, the instantaneous current was large at this time; when the sensor was combined with the target, the instantaneous current of the sensor was much larger than that without the target, indicating the successful assembly of the sensor.

[0066] III. Electrode Potential Characterization of the Enzyme-Mimicking Biofuel Cell

[0067] As shown in Figure 5 , the electrodes of the enzyme-mimicking biofuel cell were tested by chronopotentiometry. The cathode and the anode have a potential difference close to 1V, indicating that the cell has a high energy conversion efficiency, and it also means that the cell has good stability and sensitivity, which is crucial for self-powered biosensors. The high potential difference helps to improve the detection sensitivity and accuracy of the sensor, making it more reliable when monitoring biomarkers or chemical substances. In addition, this high potential difference can also reduce the energy consumption inside the cell, extend the service life of the sensor, and enhance its stability and practicality in practical applications.

[0068] IV. Verification of the Catalytic Activity of FeCo PBNCs in the Enzyme-Mimicking Biofuel Cell

[0069] As shown in Figure 6, FeCo PBNCs were separately added to different solutions for color development reactions. Figures 1a - f show the color development of 20 μL of 5 mg / mL FeCo PBNCs in different solutions. Figure 1a was added with 2 mL of ultrapure water, Figure 1b was added with 2 mL of absolute ethanol, Figure 1c was added with 2 mL of 30 mM 3,3’,5,5’-tetramethylbenzidine (TMB) solution, Figure 1d was added with 2 mL of 20 mM glucose solution, Figure 1e was added with 2 mL of 1% hydrogen peroxide solution, and Figure 1f was added with 1 mL of 1% hydrogen peroxide solution and 1 mL of 30 mM TMB solution. This fully demonstrated that FeCo PBNCs have peroxidase-like activity. Figures 2a - f show the color development when different volumes of 5 mg / mL FeCo PBNCs were added to 1 mL of 20 mM glucose solution and 1 mL of 30 mM TMB solution. Figures 3a - f are the control groups, where 5 mg / mL FeCo PBNCs under the same conditions were added to pure aqueous solutions. 20, 40, 60, 80, 100, and 120 μL of 5 mg / mL FeCo PBNCs were added to Figures 2a - f and 3a - f respectively. This fully demonstrated that FeCo PBNCs have glucose oxidase-like activity. Thus, it was shown that FeCo PBNCs have dual enzyme activities and can be used to construct enzyme-like biofuel cells.

[0070] The supporting electrolyte of the self-powered sensor constructed above is 0.01 M PBS buffer solution (pH 7.4) containing 5 mM glucose, 0.5 mM methylene blue, and 0.01% hydrogen peroxide.

[0071] Patulin aptamer sequence:

[0072] 5’-GGCCCGCCAACCCGCATCATCTACACTGATATTTTACCTT-3’.

[0073] The foregoing description of specific exemplary embodiments of the present invention is for purposes of illustration and exemplification. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many changes and variations are possible in light of the above teaching. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the invention and its practical applications, enabling those skilled in the art to implement and utilize the various different exemplary embodiments of the invention, as well as various different selections and changes. The scope of the present invention is intended to be defined by the claims and their equivalents.

Claims

1. An enzyme-like biofuel cell, characterized in that: The enzyme-like biofuel cell comprises an anode, a cathode and an electrolyte, wherein the anode is a CC@FeCo PBNCs anode, the cathode is a CC@NiMn PBNCs@AuNPs, and the electrolyte comprises glucose, hydrogen peroxide, methylene blue and PBS buffer solution.

2. A method for preparing an enzyme-like biofuel cell as claimed in claim 1, characterized in that: The fuel cell is based on FeCo PBNCs, carbon cloth CC, NiMn PBNCs and AuNPs with biological enzyme-like activity to construct an electrochemical / colorimetric dual-mode sensor cathode and anode.

3. The method according to claim 2, characterized in that The preparation of the anode includes taking 30-50 μL of 1-10 mg / mL FeCo PBNCs and dropping them on the surface of a carbon cloth electrode, and drying them to obtain the anode.

4. The method according to claim 3, characterized in that The preparation of the FeCo PBNCs includes: adding 0.1-10 g Co(OH)2 to a 0.005-0.1 mol / L K3[Fe(CN)6] solution, stirring for 1-10 hours, standing for 8-24 hours, centrifuging, washing, and freeze-drying to obtain FeCo PBNCs.

5. The method according to claim 2, characterized in that: The preparation of the cathode includes: dropping 30-50 μL of NiMnPBNCs on the surface of the carbon cloth electrode, and after drying, dropping 30-40 μL of 0.01% AuNPs solution and incubating at 35-40° C. for 4-8 hours to obtain the cathode.

6. The method according to claim 5, characterized in that The preparation of the NiMn PBNCs comprises: mixing an aqueous solution A of NiCl2 and citric acid with an aqueous solution B of an equal volume of MnCl2 and citric acid, mixing the aqueous solution A and the aqueous solution B with an aqueous solution C of K4Fe(CN)6 and excess KCl, stirring and ripening the reaction at room temperature, centrifuging and separating particles, washing and drying to obtain NiMn PBNCs.

7. The method according to claim 6, characterized in that 50-100 mL of aqueous solution A mixed with 0.8-1.4 mmol NiCl2 and 1.6-2.2 mmol citric acid was added to an equal volume of aqueous solution B mixed with 0.8-1.4 mmol MnCl2 and 1.6-2.2 mmol citric acid; the mixed solution of A and B was then poured into an aqueous solution C mixed with 0.94-1.56 mmol K4Fe(CN)6 and 1.5-2.2 g excess KCl, the solution was stirred at room temperature and aged for 12-24 h, the particles were separated by centrifugation, washed with water, and vacuum freeze-dried for 8-12 h to obtain NiMn PBNCs.

8. An application of an enzyme-like biofuel cell as claimed in any one of claims 1 to 7, characterized in that: The enzyme-like biofuel cell is used to construct a self-powered sensor.

9. A method for constructing a self-powered sensor using an enzyme-like biofuel cell as claimed in any one of claims 1 to 8, characterized in that: The method comprises the following steps: (1) A cathode primer bioprobe for enzyme-like biofuel cells, which is used to construct a self-powered sensor by specifically recognizing the detected object; (2) After adding the monitoring substance, the instantaneous current of the self-powered sensor containing different concentrations of the detection substance is measured.

10. A method for preparing a self-powered biosensor for detecting patulin aptamers using the enzyme-like biofuel cell as described in claims 1-8, characterized in that: The following steps are involved: (1) Preparation of the patulin aptamer self-powered sensor anode: FeCo PBNCs solution was drop-coated on the surface of the carbon cloth electrode, dried, and washed with water; (2) Preparation of patulin aptamer self-powered sensor cathode: NiMn PBNCs were dropped onto carbon cloth, dried, incubated with AuNPs solution, immersed in EDC / NHS solution, rinsed with water, and then patulin aptamer was dropped onto carbon cloth, incubated, MCH was added for reaction, and excess MCH was removed by washing; Wherein, the nucleotide sequence of the patulin aptamer is: 5'-GGCCCGCCAACCCGCATCATCTACACTGATATTTTACCTT-3'.

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