Construction and application of photoelectrochemical immunosensor based on HKUST-1 quenched SnO2 / NiFeOx

Abstract

The invention relates to a preparation method and application of a photoelectrochemical immunosensor based on HKUST-1 quenched SnO2 / NiFeOx, and belongs to the technical field of novel functional materials and biological sensing detection. According to the invention, SnO2 and NiFeOx nanoparticle solutions are used as substrate materials, and visible light is used as a light source to obtain light current; a photoelectrochemical sensor for detecting neuron-specific enolase (NSE) is prepared by taking a metal organic framework structure HKUST-1-NH2 as a carrier of a second antibody, and belongs to the field of photoelectrochemical sensors. A detectable signal of the sensor is in direct proportion to the concentration of an analyte in a sample, and the sensor shows high sensitivity, wide detection range and low detection limit for a target object, can realize rapid and sensitive determination of NSE in human serum, and has great application value for clinical judgment of infection types of patients.

Description

Technical Field

[0001] The present invention relates to a SnO2 and NiFeO x Preparation method and application of photoelectrochemical immunosensor based on nanoparticles, specifically using SnO2 and NiFeO x A sandwich-type photoelectrochemical immunosensor for sensitive detection of NSE was prepared using nanoparticles as a base material, which belongs to the field of new functional materials and biosensor detection technology. Background Art

[0002] The photoelectric conversion process of photoelectrochemical (PEC) immunosensors is achieved through photoelectrically active materials. When excited by light, electrons in the materials jump from the valence band to the conduction band, generating electron-hole pairs. The separation of electrons and holes generates photovoltage, which forms a photocurrent in the external circuit, converting the light signal into an electrical signal. Based on this principle, it is crucial to seek photoelectrically active materials with high conversion performance, high stability, and non-toxicity for the construction of photoelectrochemical sensors. Currently, the most studied SnO2 can only respond to ultraviolet light (<400 nm), which accounts for only 4% of the total energy of sunlight, due to its wide bandgap. The development of visible light-responsive photoelectric materials is one of the most important ways to achieve efficient photoelectric conversion. Therefore, developing metal oxides bonded to substrate materials is a particularly attractive solution to address the above issues. Bonding substrate materials to metal oxides has been used to increase the exposure of active sites; thereby promoting catalytic activity. SnO2 has been identified as an absorber support for electrocatalysts due to its abundance, low cost, and chemical stability. In addition, SnO2 can generate strong metal-support interactions with metal oxides, which can reduce self-aggregation and enhance the photoelectric signal. In this regard, the development of a SnO2 / NiFeO quenching catalyst based on HKUST-1 is promising. x Construction and application of photoelectrochemical immunosensor. Summary of the invention

[0003] One of the purposes of the present invention is to obtain a substrate material with superior performance by hydrothermal method and calcination method, and further optimize the photoelectric conversion activity by modification; The second purpose of the present invention is to use the metal organic framework material HKUST-1-NH2 to load CuS to prepare CuS-HKUST, and use 10 μL of the prepared CuS-HKUST and the complex CuS-HKUST-Ab2 of neuron-specific enolase (NSE) detection antibody Ab2 to prepare a photoelectrochemical immunosensor with high sensitivity, strong specificity and fast detection speed, so as to achieve ultra-sensitive detection of NSE under visible light conditions.

[0004] The technical solution of the present invention is as follows: 1. Quenching SnO2 / NiFeO based on HKUST-1x The method for preparing the photoelectrochemical immunosensor is characterized by comprising the following steps: 1) Cut the ITO conductive glass into 2.5×1.0 cm 2 , ultrasonically cleaned with detergent powder, acetone, ethanol and ultrapure water for 0.5 h in sequence, and dried under nitrogen; 2) 8 µL SnO2 and NiFeO x The nanoparticle solution was drop-coated on the electrode surface and stored at room temperature until dry; 3) Continue to apply 6 μL of the solution at a concentration of 10 μg·mL -1 The neuron-specific enolase (NSE) capture antibody Ab1 was placed on the surface of the ITO glass electrode, stored at room temperature until dry, and washed with ultrapure water; 4) Continue to drop 3 μL of 1% bovine serum albumin solution to block nonspecific active sites, store at room temperature until dry, and wash with ultrapure water; 5) Continue to add 6 μL of 1 fg·mL -1 ~100 ng·mL -1 A series of different concentrations of neuron-specific enolase (NSE) antigen standard solutions were dropped on the electrode surface, stored at room temperature until dry, and washed with ultrapure water; 6) CuS-HKUST was prepared by loading CuS on the metal organic framework material HKUST-1-NH2. 10 μL of the complex of CuS-HKUST and neuron-specific enolase (NSE) detection antibody Ab2, CuS-HKUST-Ab2, was drop-coated on the electrode surface and stored at room temperature until dry. The mixture was then washed with ultrapure water to obtain a photoelectrochemical immunosensor for detecting neuron-specific enolase (NSE).

[0005] The NSE antibody solution with a concentration of 1 μg / mL was obtained by diluting a 1 mg / mL NSE antibody solution purchased from Nanjing GenScript Biotechnology Co., Ltd. with phosphate buffer.

[0006] The phosphate buffer solution is prepared by mixing 0.1 mol / L disodium hydrogen phosphate solution and 0.1 mol / L potassium dihydrogen phosphate, and the pH value thereof is adjusted to 7.4.

[0007] SnO2 nanoparticle solution preparation steps: 0.0160 g of thioacetamide and 7 μL of anhydrous SnCl4 were added to a stainless steel autoclave containing a certain amount of isopropanol, and ultrasonic treatment was performed until all the raw materials were completely dissolved. Then, the mixture was placed in an oven and heated at 180 °C for 24 h. After natural cooling, the mixture was placed in a centrifuge tube and washed with water and ethanol for at least 5 times, and dried for 24 h to obtain dried SnS2. The dried SnS2 was taken out and placed in a muffle furnace, calcined at 500 °C for 2 h, and cooled to room temperature to obtain SnO2 mesoporous nanoflowers. NiFeO x Nanoparticle solution preparation steps: 1 mmol NiSO4·6H2O (0.263 g) and 1 mmol FeSO4·7H2O (0.278 g) were added to 100 mL H2O / methanol (7:3). After stirring for 0.5 h, 15 mL NaBH4 solution (0.05 mol / L) was added. The synthesized samples were collected by centrifugation, washing, and freeze-drying. Finally, the samples were heated to 420 °C (5 °C / min) in air for 2 h (expressed as NiFeO x ); Quenching SnO2 / NiFeO based on HKUST-1 x The photoelectrochemical immunosensor is constructed for the detection of NSE, wherein the detection steps are as follows: 1) The test was carried out using an electrochemical workstation with a three-electrode system, with a saturated calomel electrode as the reference electrode, a platinum wire electrode as the auxiliary electrode, and a modified ITO electrode as the working electrode in 15 mL of a phosphate buffer solution with a pH of 5.0 to 8.5 and a concentration of ascorbic acid of 0.05 to 0.25 mol / L; 2) Use the time-current method to detect the ITO glass electrode without adding the sample, set the voltage to 0 V, the running time to 120 s, and the light source wavelength to 400 ~ 500 nm; 3) After the electrodes are placed, turn on the light every 20 seconds for 20 seconds, record the photocurrent, and draw a working curve; 4) Use the ITO glass electrode with sample added instead of the ITO glass electrode without sample added for detection.

[0008] Beneficial results of the present invention 1) The present invention uses SnO2 and NiFeO x The PEC sensing model is constructed by nanomaterials. The composite of the two solves the problem of low photoelectric conversion efficiency when the material is used alone, and further amplifies the material's response to visible light by introducing a secondary antibody marker. The composite material has great application potential in photoelectric conversion. 2) The sandwich-type photoelectrochemical immunosensor prepared by the present invention is used for the detection of NSE, and has a short response time, a low detection limit, a wide linear range, and good stability. It can realize simple, rapid, highly sensitive and specific detection, and provides a new analytical method for the early clinical detection of NSE. Specific implementation plan

[0009] Example 1 Quenching SnO2 / NiFeO based on HKUST-1 x Preparation method of photoelectrochemical immunosensor: 1) Cut the ITO conductive glass into 2.5×1.0 cm 2 , ultrasonically cleaned with detergent powder, acetone, ethanol and ultrapure water for 0.5 h in sequence, and dried under nitrogen; 2) 8 µL SnO2 and NiFeO x The nanoparticle solution was drop-coated on the electrode surface and stored at room temperature until dry; 3) Continue to apply 6 μL of the solution at a concentration of 10 μg·mL -1 The neuron-specific enolase (NSE) capture antibody standard solution was applied on the surface of the ITO glass electrode, stored at room temperature until dry, and washed with ultrapure water; 4) Continue to drop 3 μL of 1% bovine serum albumin solution to block nonspecific active sites, store at room temperature until dry, and wash with ultrapure water; 5) Continue to add 6 μL of 1 fg·mL -1 ~100 ng·mL -1 A series of different concentrations of neuron-specific enolase (NSE) antigen standard solutions were dropped on the electrode surface, stored at room temperature until dry, and washed with ultrapure water; 6) CuS-HKUST was prepared by loading CuS on the metal-organic framework material HKUST-1-NH2. 5-10 μL of the complex of CuS-HKUST and neuron-specific enolase (NSE) detection antibody Ab2, CuS-HKUST-Ab2, was drop-coated on the electrode surface and stored at room temperature until dry. The electrode was then washed with ultrapure water to obtain a photoelectrochemical immunosensor for detecting neuron-specific enolase (NSE).

[0010] Example 2 Quenching SnO2 / NiFeO based on HKUST-1 x Preparation method of photoelectrochemical immunosensor: 1) Cut the ITO conductive glass into 2.5×1.0 cm 2 , ultrasonically cleaned with detergent powder, acetone, ethanol and ultrapure water for 0.5 h in sequence, and dried under nitrogen; 2) Add 8 µL Mn 0.05Cd 0.95 The S nanoparticle solution was drop-coated on the electrode surface and stored at room temperature until dry; 3) Continue to apply 6 μL of the solution at a concentration of 10 μg·mL -1 The neuron-specific enolase (NSE) capture antibody standard solution was applied on the surface of the ITO glass electrode, stored at room temperature until dry, and washed with ultrapure water; 4) Continue to drop 3 μL of 1% bovine serum albumin solution to block nonspecific active sites, store at room temperature until dry, and wash with ultrapure water; 5) Add 1 μg / mL NSE antigen solution on the surface of the modified electrode. o After incubation at 400 °C for 1 h, rinse with ultrapure water and dry naturally until a wet film is formed; 6) CuS-HKUST was prepared by loading CuS on the metal organic framework material HKUST-1-NH2. 5~10 μL of the prepared CuS-HKUST and the neuron specific enolase (NSE) detection antibody Ab2 complex CuS-HKUST-Ab2 was drop-coated on the electrode surface. o After incubation at constant temperature of C for 4 h, the electrode surface was rinsed with ultrapure water to obtain the working electrode.

[0011] Example 3 Preparation of a complex of a MOF metal organic framework structure and a neuron-specific enolase (NSE) detection antibody 1) Preparation of CuS quantum dots Under nitrogen environment and constant stirring, 0.2937 g of N-acetyl-L-cysteine ​​was dissolved in 10 mL of deionized water, and the solution was colorless. 15 mL of 0.1 mol / L CuCl2 solution was added, and the solution immediately became turbid. After uniform mixing, the pH value of the system was adjusted to 7.5 with a 1 mol / L NaOH solution. During the process of adding the NaOH solution dropwise, the solution gradually became clear. Subsequently, 1.5 mL of 0.1 mol / L Na2S solution was added, and the solution immediately turned brown-red. After sufficient reaction, highly stable near-infrared water-soluble CuS fluorescent quantum dots were obtained, which were immediately sealed and stored away from light. 2) Preparation of metal organic framework structure HKUST-1-NH2 First, 3.6 mmol (0.293 g) ZnO powder was dispersed in 8 mL distilled water and ultrasonicated for 30 min to prepare nanoslurry. After ultrasonication, 16 mL DMF was added to the ZnO nanoslurry. 7.2 mmol (1.74 g) Cu(NO3)2⋅3H2O was dissolved in 8 ml deionized water to prepare copper (II) nitrate aqueous solution. In another beaker, (0.840 g) tricarboxylic acid was dissolved in 16 ml ethanol. After the preparation of the metal solution and ligand solution, the copper nitrate aqueous solution was added to the ZnO nanoslurry under a magnetic stirring ring, and the tricarboxylic acid ethanol solution was added to the reaction mixture. After the addition of the ligand solution, the reaction mixture was stirred for 1 min and then immediately filtered with a polypropylene membrane filter with a pore size of 0.45 μm and washed with 50 mL ethanol three times. The powdered HKUST-1-UF product was dried in a hood for half an hour and then dried in a vacuum oven at 413 K for 12 h; 3) Preparation of a complex of MOF metal organic framework structure and neuron-specific enolase (NSE) detection antibody 10 mg HKUST-1-NH2 was mixed with 10 mL CuS, stirred at room temperature for 8 h, and dispersed into 2 mL phosphate buffer solution with a pH of 7.4 after centrifugation. 1 mL, 10 μg mL -1 The CuS-HKUST-Ab2 complex was prepared by mixing the CuS-HKUST-Ab2 with the neuron-specific enolase (NSE) detection antibody Ab2 and incubating at 4 ºC for 12 hours. The powder was ground into an aqueous solution with a concentration of 1 mg / mL.

[0012] Example 4 Preparation of a complex of a MOF metal organic framework structure and a neuron-specific enolase (NSE) detection antibody 1) Preparation of CuS quantum dots Under nitrogen environment and constant stirring, 0.2937 g of N-acetyl-L-cysteine ​​was dissolved in 10 mL of deionized water, and the solution was colorless. 15 mL of 0.1 mol / L CuCl2 solution was added, and the solution immediately became turbid. After uniform mixing, the pH value of the system was adjusted to 7.5 with a 1 mol / L NaOH solution. During the process of adding the NaOH solution dropwise, the solution gradually became clear. Subsequently, 1.5 mL of 0.1 mol / L Na2S solution was added, and the solution immediately turned brown-red. After sufficient reaction, highly stable near-infrared water-soluble CuS fluorescent quantum dots were obtained, which were immediately sealed and stored away from light. 2) Preparation of metal organic framework structure HKUST-1-NH2 First, 3.6 mmol (0.293 g) ZnO powder was dispersed in 8 mL distilled water and ultrasonicated for 30 min to prepare nanoslurry. After ultrasonication, 16 mL DMF was added to the ZnO nanoslurry. 7.2 mmol (1.74 g) Cu(NO3)2⋅3H2O was dissolved in 8 ml deionized water to prepare copper (II) nitrate aqueous solution. In another beaker, (0.840 g) tricarboxylic acid was dissolved in 16 ml ethanol. After the preparation of the metal solution and ligand solution, the copper nitrate aqueous solution was added to the ZnO nanoslurry under a magnetic stirring ring, and the tricarboxylic acid ethanol solution was added to the reaction mixture. After the addition of the ligand solution, the reaction mixture was stirred for 1 min and then immediately filtered with a polypropylene membrane filter with a pore size of 0.45 μm and washed with 50 mL ethanol three times. The powdered HKUST-1-UF product was dried in a hood for half an hour and then dried in a vacuum oven at 413 K for 12 h; 3) Preparation of a complex of MOF metal organic framework structure and neuron-specific enolase (NSE) detection antibody 10 mg HKUST-1-NH2 was mixed with 10 mL CuS, stirred at room temperature for 8 h, and dispersed into 2 mL phosphate buffer solution with a pH of 7.4 after centrifugation. 1 mL, 10 μg mL -1 The CuS-HKUST-Ab2 complex was obtained by mixing the CuS-HKUST-Ab2 with the neuron-specific enolase (NSE) detection antibody Ab2 and incubating at 4 ºC for 12 hours. The powder was ground into an aqueous solution with a concentration of 3 mg / mL.

[0013] Example 5 Preparation of a complex of a MOF metal organic framework structure and a neuron-specific enolase (NSE) detection antibody 1) Preparation of CuS quantum dots Under nitrogen environment and constant stirring, 0.2937 g of N-acetyl-L-cysteine ​​was dissolved in 10 mL of deionized water, and the solution was colorless. 15 mL of 0.1 mol / L CuCl2 solution was added, and the solution immediately became turbid. After uniform mixing, the pH value of the system was adjusted to 7.5 with a 1 mol / L NaOH solution. During the process of adding the NaOH solution dropwise, the solution gradually became clear. Subsequently, 1.5 mL of 0.1 mol / L Na2S solution was added, and the solution immediately turned brown-red. After sufficient reaction, highly stable near-infrared water-soluble CuS fluorescent quantum dots were obtained, which were immediately sealed and stored away from light. 2) Preparation of metal organic framework structure HKUST-1-NH2 First, 3.6 mmol (0.293 g) ZnO powder was dispersed in 8 mL distilled water and ultrasonicated for 30 min to prepare nanoslurry. After ultrasonication, 16 mL DMF was added to the ZnO nanoslurry. 7.2 mmol (1.74 g) Cu(NO3)2⋅3H2O was dissolved in 8 ml deionized water to prepare copper (II) nitrate aqueous solution. In another beaker, (0.840 g) tricarboxylic acid was dissolved in 16 ml ethanol. After the preparation of the metal solution and ligand solution, the copper nitrate aqueous solution was added to the ZnO nanoslurry under a magnetic stirring ring, and the tricarboxylic acid ethanol solution was added to the reaction mixture. After the addition of the ligand solution, the reaction mixture was stirred for 1 min and then immediately filtered with a polypropylene membrane filter with a pore size of 0.45 μm and washed with 50 mL ethanol three times. The powdered HKUST-1-UF product was dried in a hood for half an hour and then dried in a vacuum oven at 413 K for 12 h; 3) Preparation of a complex of MOF metal organic framework structure and neuron-specific enolase (NSE) detection antibody 10 mg HKUST-1-NH2 was mixed with 10 mL CuS, stirred at room temperature for 8 h, and dispersed into 2 mL phosphate buffer solution with a pH of 7.4 after centrifugation. 1 mL, 10 μg mL -1 The CuS-HKUST-Ab2 complex was prepared by mixing the CuS-HKUST-Ab2 with the neuron-specific enolase (NSE) detection antibody Ab2 and incubating at 4 ºC for 12 hours. The powder was ground into an aqueous solution with a concentration of 5 mg / mL.

[0014] Example 6 Detection of NSE: (1) The test was carried out using an electrochemical workstation with a three-electrode system, with a saturated calomel electrode as the reference electrode, a platinum wire electrode as the auxiliary electrode, and the prepared ITO modified electrode as the working electrode. The test was carried out in 15 mL of PBS buffer solution with a pH of 5.5 and a concentration of 0.1 mol / L ascorbic acid. (2) The labeled and unlabeled NSE mixed standard solutions were detected using the time-current method, with the voltage set to 0 V, the running time to 120 s, and the light source wavelength to 400 nm. (3) After the electrodes are placed, turn on the light every 20 seconds for 20 seconds, record the photocurrent, and draw a working curve; (4) Test with a NSE sample solution of known concentration.

[0015] Example 7 Detection of NSE: (1) The test was carried out using an electrochemical workstation with a three-electrode system, with a saturated calomel electrode as the reference electrode, a platinum wire electrode as the auxiliary electrode, and the prepared ITO modified electrode as the working electrode. The test was carried out in 15 mL of PBS buffer solution with a pH of 7.4 and a concentration of 0.2 mol / L ascorbic acid. (2) The labeled and unlabeled NSE mixed standard solutions were detected using the time-current method, with the voltage set to 0 V, the running time to 120 s, and the light source wavelength to 450 nm. (3) After the electrodes are placed, turn on the light every 20 seconds for 20 seconds, record the photocurrent, and draw a working curve; (4) Test with a NSE sample solution of known concentration.

[0016] Example 8 Detection of NSE: (1) The test was carried out using an electrochemical workstation with a three-electrode system, with a saturated calomel electrode as the reference electrode, a platinum wire electrode as the auxiliary electrode, and the prepared ITO modified electrode as the working electrode. The test was carried out in 15 mL of PBS buffer solution with a pH of 8.0 and a concentration of 1.5 mol / L ascorbic acid. (2) The labeled and unlabeled NSE mixed standard solutions were detected using the time-current method, with the voltage set to 0 V, the running time to 120 s, and the light source wavelength to 500 nm. (3) After the electrodes are placed, turn on the light every 20 seconds for 20 seconds, record the photocurrent, and draw a working curve; (4) Test with a NSE sample solution of known concentration.

Claims

1. Quenching SnO2 / NiFeO based on HKUST-1 x The method for preparing a photoelectrochemical immunosensor is characterized in that: The following steps are involved: 1) Cut the ITO conductive glass into 2.5×1.0 cm 2 , ultrasonically cleaned with detergent powder, acetone, ethanol and ultrapure water for 0.5 h in sequence, and dried under nitrogen; 2) 8 µL SnO2 and NiFeO x The nanoparticle solution was drop-coated on the electrode surface and stored at room temperature until dry; 3) Continue to apply 6 μL of the solution at a concentration of 10 μg·mL -1 The neuron-specific enolase (NSE) capture antibody Ab1 was placed on the surface of the ITO glass electrode, stored at room temperature until dry, and washed with ultrapure water; 4) Continue to drop 3 μL of 1% bovine serum albumin solution to block nonspecific active sites, store at room temperature until dry, and wash with ultrapure water; 5) Continue to add 6 μL of 1 fg·mL -1 ~100 ng·mL -1 A series of different concentrations of neuron-specific enolase (NSE) antigen standard solutions were dropped on the electrode surface, stored at room temperature until dry, and washed with ultrapure water; 6) CuS-HKUST was prepared by loading CuS on the metal organic framework material HKUST-1-NH2. 10 μL of the complex of CuS-HKUST and neuron-specific enolase (NSE) detection antibody Ab2, CuS-HKUST-Ab2, was drop-coated on the electrode surface and stored at room temperature until dry. The mixture was then washed with ultrapure water to obtain a photoelectrochemical immunosensor for detecting neuron-specific enolase (NSE).

2. The method of quenching SnO2 / NiFeO based on HKUST-1 as claimed in claim 1 x Preparation method of photoelectrochemical immunosensor, the SnO2 and NiFeO x A nanoparticle solution, characterized in that The preparation steps are as follows: 1) Add 0.0160 g of thioacetamide and 7 μL of anhydrous SnCl4 into a stainless steel autoclave containing a certain amount of isopropanol, and perform ultrasonication until all the raw materials are completely dissolved. Then, place the mixture in an oven and heat it at 180 °C for 24 h. After natural cooling, wash the mixture in a centrifuge tube with water and ethanol for at least 5 times and dry it for 24 h to obtain dried SnS2. Take it out and place it in a muffle furnace. Calcine it at 500 °C for 2 h and cool it to room temperature to obtain SnO2 mesoporous nanoflowers. 2) 1 mmol NiSO4·6H2O (0.263 g) and 1 mmol FeSO4·7H2O (0.278 g) were added to 100 mL H2O / methanol (7:3). After stirring for 0.5 h, 15 mL NaBH4 solution (0.05 mol / L) was added. The synthesized sample was collected by centrifugation, washing and freeze-drying. Finally, the sample was heated to 420 °C (5 °C / min) in air for 2 h (expressed as NiFeO x ).

3. The method of quenching SnO2 / NiFeO based on HKUST-1 as claimed in claim 1 x The preparation method of the photoelectrochemical immunosensor, the complex of the MOF metal organic framework structure and the neuron-specific enolase (NSE) detection antibody, is characterized in that: The preparation steps are as follows: 1) Preparation of CuS quantum dots Under nitrogen environment and constant stirring, 0.2937 g N-acetyl-L-cysteine ​​was dissolved in 10 mL deionized water. The solution was colorless. 15 mL of 0.1 mol / L CuCl2 solution was added. The solution immediately became turbid. After mixing evenly, the pH value of the system was adjusted to 7.5 with 1 mol / L NaOH solution. During the process of adding NaOH solution, the solution gradually became clear. Subsequently, 1.5 mL of 0.1 mol / L Na2S solution was added. The solution immediately turned brown-red. After sufficient reaction, highly stable near-infrared water-soluble CuS fluorescent quantum dots were obtained, which were immediately sealed and stored away from light. 2) Preparation of metal organic framework structure HKUST-1-NH2 291.0 mg Co(NO3)2·6H2O and a certain amount of 2-methylimidazole were dissolved in 25.0 mL methanol, respectively. Then, the 2-methylimidazole solution was poured into the Co(NO3)2·6H2O solution and allowed to react at room temperature for 24 h. Finally, the mixture was centrifuged in a high-speed centrifuge to obtain a purple HKUST-1 precipitate. The precipitate was then dispersed in ethanol and stirred for 48 h to exchange the solvent N,N-dimethylformamide. After centrifugation again, it was placed in a vacuum drying oven for drying. In order to enlarge the pore size of HKUST-1-NH2, the dried powder was placed in a tube furnace and reacted at 200-300 ºC for 6 h to obtain HKUST-1-NH2 with a larger pore size. 3) Preparation of a complex of MOF metal organic framework structure and neuron-specific enolase (NSE) detection antibody 10 mg HKUST-1-NH2 was mixed with 10 mL CuS, stirred at room temperature for 8 h, and dispersed into 2 mL phosphate buffer solution with a pH of 7.4 after centrifugation. 1 mL, 10 μg mL -1 The mixture was mixed with the neuron-specific enolase (NSE) detection antibody Ab2 and incubated at 4 ºC for 12 hours to obtain the CuS-HKUST-Ab2 complex.

4. The method of quenching SnO2 / NiFeO based on HKUST-1 as claimed in claim 1 x Preparation method of photoelectrochemical immunosensor, neuron-specific enolase (NSE) antigen standard solution with different concentrations was 1 mg mL -1 The neuron-specific enolase (NSE) solution was diluted with phosphate buffered saline.

5. A method for detecting neuron-specific enolase (NSE) based on a photoelectrochemical sensor, characterized in that: The detection steps are as follows: 1) The test was carried out using an electrochemical workstation with a three-electrode system, with a saturated calomel electrode as the reference electrode, a platinum wire electrode as the auxiliary electrode, and a modified ITO electrode as the working electrode in 15 mL of a phosphate buffer solution with a pH of 5.0 to 8.5 and a concentration of ascorbic acid of 0.05 to 0.25 mol / L; 2) Use the time-current method to detect the ITO glass electrode without adding the sample, set the voltage to 0 V, the running time to 120 s, and the light source wavelength to 400 ~ 500 nm; 3) After the electrodes are placed, turn on the light every 20 seconds for 20 seconds, record the photocurrent, and draw a working curve; 4) Use the ITO glass electrode with sample added instead of the ITO glass electrode without sample added for detection.