Preparation method and application of photoelectrochemical cancer antigen 125 sensor based on signal dual amplification

Abstract

The invention discloses a preparation method and application of a photoelectrochemical cancer antigen 125 sensor based on signal double amplification, belongs to the field of analytical chemistry, and adopts a Z-type W18O49 / ZnIn2S4 heterojunction as a photoelectrochemical sensing matrix material for realizing high light current output for the first time. And meanwhile, copper oxide / polydopamine is used as a marker to realize double amplification of photoelectric signals, so that efficient and sensitive detection of the cancer antigen 125 sensor is realized.

Description

Technical Field

[0001] This invention belongs to the field of analytical chemistry, specifically relating to a method for preparing a photoelectrochemical cancer antigen 125 sensor based on dual signal amplification and its application. Background Technology

[0002] Cancer antigen 125 (CA125), a high-molecular-weight mucin glycoprotein antigen, plays a significant role in the auxiliary diagnosis of ovarian cancer. Changes in its level are crucial indicators for early diagnosis, postoperative recurrence monitoring, and treatment efficacy evaluation in ovarian cancer patients. Therefore, establishing a highly sensitive and rapid CA125 detection method to achieve accurate screening and rapid identification of ovarian cancer is key to reducing mortality and prolonging survival for ovarian cancer patients. In recent years, photoelectrochemical sensors have been widely used in disease analysis due to their advantages such as low background signal, high efficiency, and wide linear range. Summary of the Invention

[0003] This invention provides a method for preparing a photoelectrochemical cancer antigen 125 sensor based on dual signal amplification and a method for detecting cancer antigen 125 using the sensor.

[0004] A method for preparing a photoelectrochemical cancer antigen 125 sensor based on dual signal amplification includes the following steps:

[0005] Step 1: Deposit Z-type W ... 18 O 49 The ZnIn2S4 heterojunction, after being modified with carboxyl groups of mercaptoacetic acid, was activated with a 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide / N-hydroxysuccinimide system to obtain the electrode;

[0006] Step 2: Immerse the electrode obtained in Step 1 in the first antibody solution of cancer antigen 125 for incubation and washing, then block the remaining active sites with bovine serum albumin solution and perform a second washing.

[0007] Step 3: React the electrode obtained in Step 2 with cancer antigen 125, then add copper oxide / polydopamine nanocomposite material chelated with the second antibody of cancer antigen 125 for secondary incubation, and after washing, obtain a photoelectrochemical cancer antigen 125 sensor based on signal dual amplification.

[0008] Furthermore, in step one, the Z-shaped W 18 O 49 The preparation method of / ZnIn2S4 heterojunction is as follows:

[0009] (1) In a glove box, 1-1.2 mmol of tungsten hexachloride was added to 75 mL of ethanol and stirred for 30 minutes. The mixture was then transferred to a high-pressure reactor and reacted at 170-180 °C for 24 hours. After centrifugation, the product was washed three times each with deionized water and anhydrous ethanol and dried under vacuum to obtain W. 18 O 49 ;

[0010] (2) Dissolve 0.3-0.5 mmol zinc acetate dihydrate, 0.7-0.9 mmol indium chloride tetrahydrate, and 1.5-1.7 mmol thioacetamide in 30 mL of an aqueous ethanol solution (ethanol to water volume ratio of 1:1), and then disperse 30-40 mg of W into the above solution. 18 O 49 The precursor solution was obtained; the precursor solution was transferred to a high-pressure reactor and reacted at 170-180℃ for 24 hours; after centrifugation, it was washed with deionized water and anhydrous ethanol and then dried to obtain W. 18 O 49 / ZnIn2S4 composite material.

[0011] Furthermore, in step two, the preparation method of the copper oxide / polydopamine nanocomposite material chelated with the second antibody of cancer antigen 125 is as follows:

[0012] (1) Dissolve 1-2 mmol copper sulfate pentahydrate and 10-12 mmol glucose in 100 mL distilled water; while stirring, add 0.04 mol / L, 20-25 mL ammonia and 0.20 mol / L, 20-25 mL sodium hydroxide solution dropwise to the above solution; then quickly add 0.03 mol / L, 50-60 mL ascorbic acid solution and stir for 1 hour; after centrifugation, wash the obtained product three times each with deionized water and ethanol, and dry it under vacuum at 50 °C to obtain copper oxide; then weigh 30 mg copper oxide and 5-7 mg dopamine hydrochloride and disperse them in 30 mL of 10 mmol / L, pH 8.5 tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution; after stirring overnight, centrifuge, wash the obtained product with ultrapure water, and dry it under vacuum to obtain copper oxide / polydopamine nanocomposite material;

[0013] (2) Take 1 mL of 10 μg / mL cancer antigen 125 secondary antibody and mix it with 1 mL of 4 ~ 6 mg / mL copper oxide / polydopamine solution and incubate overnight at 4 °C; then add 200 μL of 0.1 ~ 0.3 wt% bovine serum albumin (BSA) solution, centrifuge and separate, and finally wash the copper oxide / polydopamine nanocomposite material chelated by the secondary antibody with deionized water and redisperse it in 1 mL of phosphate buffer for later use.

[0014] Furthermore, the specific operation of step one is as follows:

[0015] Take 10 µL of Z-type W prepared with 3 ~ 5 mg / mL S1. 18 O 49 / ZnIn2S4 heterojunction aqueous solution is dropped onto a surface with an area of ​​1 × 2 cm² 2 Electrodes were prepared from conductive glass; after drying at room temperature, 10 μL of a 3-5 mmol / L mercaptoacetic acid solution was added dropwise; then 10 μL of a 0.1-0.3 mol / L aqueous solution of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide / N-hydroxysuccinimide was added dropwise to the electrode, and the carboxyl groups were activated after incubation for 30 minutes.

[0016] Z-shaped W 18 O 49 / ZnIn2S4 heterojunction dissolved in deionized water to prepare 3 ~ 5 mg / mL Z-type W 18 O 49 / ZnIn2S4 heterojunction aqueous solution;

[0017] Weigh a certain mass of mercaptoacetic acid and dissolve it in 50 mL of deionized water to prepare a 3-5 mmol / L mercaptoacetic acid aqueous solution;

[0018] Weigh out equal masses of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide, respectively, and dissolve them in 1 mL of deionized water to prepare a mixed aqueous solution of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide / N-hydroxysuccinimide; the total concentration of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide is 0.1 ~ 0.3 mol / L, and the molar ratio of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide to N-hydroxysuccinimide is 1:1.

[0019] Furthermore, the specific operation of step two is as follows:

[0020] 8 µL of the first antibody solution of cancer antigen 125 (8 ~ 10 µg / mL) was drop-coated onto the surface of the electrode prepared in step one, incubated for 1 hour, and then washed with a phosphate buffer solution of pH 7.4 and 0.1 mol / L.

[0021] Add 6 µL of 0.1 ~ 0.3 wt% bovine serum albumin solution, incubate for 30 minutes to block nonspecific active sites, and wash with pH 7.4, 0.1 mol / L phosphate buffer solution;

[0022] Furthermore, the specific operation of step three is as follows:

[0023] Add 8 μL of solution with a concentration of 1 × 10⁻⁶. -5 The electrode was incubated with a cancer antigen 125 solution of U / mL to 200 U / mL for 1 hour, washed with a phosphate buffer solution of pH 7.4 and 0.1 mol / L, and then 8 μL of a copper oxide / polydopamine nanocomposite solution chelated with a secondary antibody of 3 to 5 mg / mL was added to the electrode surface. After incubation for 30 minutes, the electrode was washed with a phosphate buffer solution of pH 7.4 and 0.1 mol / L to obtain a photoelectrochemical cancer antigen 125 sensor based on dual signal amplification.

[0024] The present invention also provides a method for detecting cancer antigen 125 based on the aforementioned sensing platform, the method being as follows:

[0025] (1) Setup of photoelectrochemical detection system

[0026] A three-electrode system was used for testing, specifically configured as follows: an Ag / AgCl electrode was used as the reference electrode, a platinum wire electrode was used as the counter electrode, and a photoelectrochemical cancer antigen 125 sensor based on dual signal amplification was used as the working electrode.

[0027] During the experiment, the electrochemical workstation was used in conjunction with an LED light source;

[0028] (2) The photoelectrochemical signal intensity generated by cancer antigen 125 standard solutions of different concentrations was detected by the photoelectrochemical detection system, and the working curve was plotted;

[0029] (3) Replace the cancer antigen 125 standard solution with the test sample solution for determination, and obtain the concentration of cancer antigen 125 in the test sample solution according to the working curve.

[0030] Furthermore, in the method for detecting cancer antigen 125 based on the aforementioned sensing platform:

[0031] The electrochemical workstation was used in conjunction with an LED light source, with the following parameters set: voltage adjusted to 0 ~ 0.2 V, LED light wavelength set to 405 ~ 450 nm, and running time set to 100 seconds.

[0032] To plot the working curve, the photoelectrochemical signal intensity generated by different concentrations of cancer antigen 125 standard solution was detected in 10 mL of PBS buffer solution containing 0.1 mol / L to 0.3 mol / L ascorbic acid at pH 7.0 to 8.5 using an electrochemical workstation, and the working curve was plotted.

[0033] Beneficial effects:

[0034] (1) The present invention successfully synthesized copper oxide / polydopamine composite material and applied it to the signal amplification of the photoelectrochemical detection of cancer antigen 125. The p-type semiconductor copper oxide and polydopamine with good light absorption properties can compete with the matrix material for electron donors and visible light, thereby realizing the dual amplification of photoelectric signals and greatly improving the sensitivity of the sensing platform.

[0035] (2) This invention is the first to incorporate Z-type W 18 O 49 / ZnIn2S4 heterojunction as a photoelectrochemical sensing matrix material, W 18 O 49 The band structure matched with ZnIn2S4 forms a Z-scheme heterojunction, promoting the separation of photogenerated electron-hole pairs; furthermore, W 18 O 49 The local surface plasmon resonance effect further improves the photoelectric conversion efficiency, thereby enabling the sensor to output strong photocurrent.

[0036] (3) The photoelectrochemical cancer antigen 125 sensor constructed in this invention based on dual signal amplification can be applied to the sensitive detection of cancer antigen 125. This detection method has the following advantages: simple operation, short response time, good stability, and wide signal linear range (from 1 × 10⁻⁶). -4 It has a detection limit of U / mL to 200 U / mL and an extremely low detection limit (as low as 3.1 × 10⁻⁶). -5 U / mL). Attached Figure Description

[0037] Figure 1 W is based on Example 1 18 O 49 and Z-type W 18 O 49 Scanning electron microscope image of ZnIn2S4 material;

[0038] Figure 2 Scanning electron microscope images of copper oxide and copper oxide / polydopamine composite material obtained in Example 2;

[0039] Figure 3The operating curve of the photoelectrochemical cancer antigen 125 sensor obtained in Example 3 is: I = 5.97 – 1.67 lg c, R 2 =98.7%; linear range is 1 × 10 -4 U / mL to 200 U / mL; LOD = 3.1 × 10 -5 U / mL (S / N=3). Detailed Implementation

[0040] The technical solution of the present invention will be described in detail below through embodiments, but the scope of protection of the present invention is not limited to the embodiments described.

[0041] In this invention, cancer antigen 125 and its first and second antibodies were purchased from Sangon Biotech (Shanghai) Co., Ltd. Dopamine hydrochloride was purchased from Shanghai Maclean's Biochemical Technology Co., Ltd. Cancer antigen 125 and its first and second antibodies were diluted with phosphate buffer solution at pH 7.4 to obtain a 10 µg / mL solution of the first antibody against cancer antigen 125, a 10 mg / mL solution of the second antibody against cancer antigen 125, and a 10 U / mL solution of cancer antigen 125.

[0042] Example 1

[0043] A Z-type W 18 O 49 Preparation method of ZnIn2S4 heterojunction:

[0044] (1) In a glove box, 1.2 mmol of tungsten hexachloride was added to 75 mL of ethanol and stirred for 30 minutes; then the mixture was transferred to a high-pressure reactor and reacted at 180 °C for 24 hours; after centrifugation, the product was washed three times each with deionized water and anhydrous ethanol, and dried under vacuum to obtain W. 18 O 49 ;

[0045] (2) Dissolve 0.4 mmol zinc acetate dihydrate, 0.8 mmol indium chloride tetrahydrate and 1.6 mmol thioacetamide in 30 mL of ethanol-water solution with a volume ratio of 1:1, and then disperse 40 mg of W into the above solution. 18 O 49 The previously prepared solution was transferred to a high-pressure reactor and reacted at 170 °C for 24 hours. After centrifugation, the solution was washed with deionized water and anhydrous ethanol and then dried to obtain W. 18 O 49 / ZnIn2S4 composite material.

[0046] According to W 18 O 49The energy level structure positions of ZnIn2S4 and the superoxide radicals measured by electron paramagnetic resonance indirectly prove the W obtained in this embodiment. 18 O 49 / ZnIn2S4 composite material is a Z-type W 18 O 49 / ZnIn2S4 heterojunction Figure 1 W is based on Example 1 18 O 49 and Z-type W 18 O 49 Scanning electron microscope image of ZnIn2S4 material, left image is W 18 O 49 The scanning electron microscope images show microspheres with diameters ranging from 1 to 2 μm. After modification with ZnIn2S4, as shown... Figure 1 As shown in the right figure, W can be clearly seen. 18 O 49 The ZnIn2S4 material forms a flower-shaped structure.

[0047] Example 2

[0048] A method for preparing a copper oxide nanocomposite material chelated with a second antibody:

[0049] (1) Dissolve 1.5 mmol copper sulfate pentahydrate and 10 mmol glucose in 100 mL distilled water; while stirring, add 0.04 mol / L, 25 mL ammonia water and 0.20 mol / L, 25 mL sodium hydroxide solution dropwise to the above solution; then quickly add 0.03 mol / L, 50 mL ascorbic acid solution and stir for 1 hour; after centrifugation, wash the obtained product three times each with deionized water and ethanol, and dry it under vacuum at 50 °C to obtain copper oxide; then weigh 30 mg copper oxide and 6 mg dopamine hydrochloride and disperse them in 30 mL of 10 mmol / L, pH 8.5 tris(hydroxymethyl)aminomethane-hydrochloric acid buffer; after stirring overnight, centrifuge, wash the obtained product with ultrapure water, and dry it under vacuum to obtain copper oxide / polydopamine nanocomposite material;

[0050] Weigh 4 mg of copper oxide / polydopamine nanocomposite material and disperse it in 1 mL of phosphate buffer to prepare a 4 mg / mL copper oxide / polydopamine solution for later use.

[0051] (2) Take 1 mL of 10 μg / mL cancer antigen 125 secondary antibody and mix it with 1 mL of 4 mg / mL copper oxide / polydopamine solution and incubate overnight at 4 °C; then add 200 μL of 0.1 wt% bovine serum albumin (BSA) solution, centrifuge and separate, and finally wash the copper oxide / polydopamine nanocomposite material chelated by the secondary antibody with deionized water and redisperse it in 1 mL of phosphate buffer for later use.

[0052] Figure 2 The images show scanning electron microscope (SEM) images of copper oxide and copper oxide / polydopamine materials obtained in Example 2. The left image shows the SEM image of copper oxide, which can be seen to be microspheres. After modification with polydopamine, as shown... Figure 2 As shown in the right figure, it can be clearly seen that a polydopamine coating is applied to the surface of copper oxide, thus forming a copper oxide / polydopamine nanocomposite material.

[0053] Example 3

[0054] A photoelectrochemical cancer antigen 125 sensor based on dual signal amplification, characterized by the following preparation steps:

[0055] (1) Take 10 µL of the Z-type W prepared in step one with a concentration of 3 mg / mL. 18 O 49 / ZnIn2S4 heterojunction aqueous solution is dropped onto a surface with an area of ​​1 × 2 cm 2 Electrodes were prepared from conductive glass; after drying at room temperature, 10 μL of a 3 mmol / L thioglycolic acid aqueous solution was added dropwise; then 10 μL of a 1:1 molar ratio of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide / N-hydroxysuccinimide mixed aqueous solution was added dropwise to the electrode, and the carboxyl groups were activated after incubation for 30 minutes; the total concentration of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide in the 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide / N-hydroxysuccinimide mixed aqueous solution was 0.2 mol / L.

[0056] (2) Drop 8 µL of the first antibody solution of cancer antigen 125 at 10 µg / mL onto the surface of the electrode prepared in step (1), incubate for 1 hour, and wash with a phosphate buffer solution at pH 7.4 and 0.1 mol / L.

[0057] (3) Add 6 µL of 0.1 wt% bovine serum albumin solution, incubate for 30 minutes to block non-specific active sites, and wash with pH 7.4, 0.1 mol / L phosphate buffer solution;

[0058] (4) Add 8 μL of cancer antigen 125 solution with a concentration of 10 U / m and incubate for 1 hour. After washing with pH 7.4, 0.1 mol / L phosphate buffer solution, add 8 μL of copper oxide / polydopamine nanocomposite solution chelated with the second antibody of cancer antigen 125 at 3 mg / mL on the electrode surface. After incubation for 30 minutes, rinse with pH 7.4, 0.1 mol / L phosphate buffer solution to obtain photoelectrochemical cancer antigen 125 sensor based on signal dual amplification.

[0059] Example 4

[0060] An application of a photoelectrochemical cancer antigen 125 sensor based on dual signal amplification, characterized by the following steps:

[0061] (1) Photoelectrochemical detection of cancer antigen 125 was performed using a three-electrode system. The specific configuration was as follows: an Ag / AgCl electrode was used as the reference electrode, a platinum wire electrode was used as the counter electrode, and a photoelectrochemical cancer antigen 125 sensor based on double signal amplification was used as the working electrode. During the experiment, the electrochemical workstation was connected to an LED light source, the voltage was adjusted to 0 V, the LED light wavelength was 450 nm, and the running time was 100 seconds.

[0062] (2) In 10 mL of phosphate buffer solution containing 0.1 mol / L ascorbic acid at pH 7.4, the photoelectrochemical signal intensity generated by different concentrations of cancer antigen 125 standard solution was detected by an electrochemical workstation, and a working curve was plotted. The photoelectrochemical signal intensity of the sample solution to be tested was detected, and the concentration of cancer antigen 125 in the sample solution to be tested was obtained according to the working curve.

[0063] Figure 3 The operating curve of the photoelectrochemical cancer antigen 125 sensor obtained in Example 4 is: I = 5.97 – 1.67 lg c, R 2 =98.7%; where I represents photocurrent in μA, and c represents the concentration of cancer antigen 125 in U / mL; the linear range is 1 × 10⁻⁶. -4 U / mL to 200 U / mL, LOD = 3.1 × 10 -5 U / mL (S / N=3, where S / N represents the ratio of photocurrent intensity to background noise signal intensity), it can be seen that the working curve obtained based on the photoelectrochemical cancer antigen 125 sensor in Example 4 has a wider detection range and a lower detection limit, and can achieve more sensitive and accurate detection of cancer antigen 125.

[0064] Experiments have demonstrated that the dual signal amplification strategy designed in this invention can significantly improve the sensor's detection sensitivity. The principle of this invention's detection method is that cancer antigen 125, after being specifically recognized by the copper oxide / polydopamine nanocomposite material chelated by the second antibody, can effectively amplify its signal, making the detection of lower concentrations possible. Furthermore, the photoelectrochemical cancer antigen 125 sensor with dual signal amplification designed in this invention also provides a novel method for the analysis and detection of other disease biomarkers.

[0065] As described above, although the invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the invention itself. Various changes in form and detail may be made without departing from the spirit and scope of the invention.

Claims

1. A method for preparing a photoelectrochemical cancer antigen 125 sensor based on dual signal amplification, characterized in that, Includes the following steps: Step one, depositing Z-type W on the surface of conductive glass 18 O 49 / ZnIn2S4 heterojunction, after modification by mercaptoacetic acid carboxyl, activation by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide / N-hydroxysuccinimide system, to obtain an electrode; Step 2: Immerse the electrode obtained in Step 1 in the first antibody solution of cancer antigen 125 for incubation and washing, then block the remaining active sites with bovine serum albumin solution and perform a second washing. Step 3: React the electrode obtained in Step 2 with cancer antigen 125, then add copper oxide / polydopamine nanocomposite material chelated with the second antibody of cancer antigen 125 for secondary incubation, and after washing, obtain a photoelectrochemical cancer antigen 125 sensor based on signal dual amplification.

2. The preparation method according to claim 1, characterized in that, In step one, Z-type W 18 O 49 The preparation method of the / ZnIn2S4 heterojunction is as follows: (1) In a glove box, tungsten hexachloride was added to ethanol and stirred for a period of time. Then, it was transferred to a high-pressure reactor and reacted at 170-180 °C for a period of time. After centrifugation, the product was washed and dried to obtain W. 18 O 49 ; (2) Dissolve 0.3-0.5 mmol zinc acetate dihydrate, 0.7-0.9 mmol indium chloride tetrahydrate, and 1.5-1.7 mmol thioacetamide in an aqueous ethanol solution, and then disperse 30-40 mg of W into the solution. 18 O 49 The precursor solution was obtained and transferred to a high-pressure reactor. After reacting at 170-180 °C for a period of time, centrifugation was performed, and the resulting product was washed and dried to obtain W. 18 O 49 / ZnIn2S4 composite material.

3. The preparation method according to claim 1, characterized in that, In step two, the copper oxide / polydopamine nanocomposite material chelated with the second antibody of cancer antigen 125 is prepared by the following method: (1) Weigh 30 mg of copper oxide and 5 ~ 7 mg of dopamine hydrochloride and disperse them in 30 mL of 10 mmol / L, pH 8.5 tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution; stir overnight, centrifuge, wash the product with ultrapure water, and vacuum dry to obtain copper oxide / polydopamine nanocomposite material. (2) Take 1 mL of 10 μg / mL secondary antibody against cancer antigen 125 and mix it with 1 mL of 4 ~ 6 mg / mL copper oxide / polydopamine solution and incubate overnight at 4 °C; then add 200 μL of 0.1 ~ 0.3 wt% bovine serum albumin (BSA) solution, centrifuge to obtain copper oxide / polydopamine nanocomposite material chelated with the secondary antibody against cancer antigen 125, wash with deionized water and redisperse in 50 mL phosphate buffer for later use.

4. The preparation method according to claim 1, characterized in that, The specific steps for step one are as follows: Take 3-5 mg / mL of Z-type W 18 O 49 An electrode was prepared by dropping an aqueous solution of ZnIn2S4 heterojunction onto a conductive glass substrate. After drying at room temperature, a 3-5 mmol / L aqueous solution of mercaptoacetic acid was added. Subsequently, a mixed aqueous solution of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide / N-hydroxysuccinimide was added to the electrode, and the electrode was incubated for 30 minutes to activate the carboxyl groups. The total concentration of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide in the mixed aqueous solution was 0.1-0.3 mol / L.

5. The preparation method according to claim 1, characterized in that, The specific steps for step two are as follows: First, drop the first antibody solution of cancer antigen 125 onto the electrode surface prepared in step one, incubate for 1 hour, and then wash with phosphate buffer solution; the concentration of the first antibody solution of cancer antigen 125 is 8 ~ 10 µg / mL. Then, 0.1-0.3 wt% bovine serum albumin solution was added to the electrode surface, and after incubation for 30 minutes to block non-specific active sites, it was washed with phosphate buffer solution.

6. The preparation method according to claim 1, characterized in that, The specific steps for step three are as follows: First, drop 1 × 10⁻⁶ ppm onto the surface of the electrode obtained in step two. -5 Incubate with a cancer antigen 125 solution of U / mL ~ 200 U / mL for 1 hour, then wash with phosphate buffer solution; Then, a copper oxide / polydopamine nanocomposite solution chelated with the second antibody of cancer antigen 125 was added dropwise to the electrode surface. After incubation for 30 minutes, it was rinsed with phosphate buffer solution to obtain a photoelectrochemical cancer antigen 125 sensor based on signal dual amplification.

7. The application of the photoelectrochemical cancer antigen 125 sensor based on signal dual amplification prepared by the preparation method of claim 1 in the detection of cancer antigen 125.

8. The application according to claim 7, characterized in that, The application method is as follows: (1) Setup of the photoelectrochemical detection system; A three-electrode system was used for testing, specifically configured as follows: an Ag / AgCl electrode as the reference electrode, a platinum wire electrode as the counter electrode, and a photoelectrochemical cancer antigen 125 sensor based on dual signal amplification as the working electrode; during the experiment, the electrochemical workstation was used in conjunction with an LED light source. (2) The intensity of photoelectrochemical signals generated by cancer antigen 125 standard solutions of different concentrations was detected by photoelectrochemical detection system, and working curves were plotted; (3) The test sample solution is used instead of the cancer antigen 125 standard solution for determination, and the concentration of cancer antigen 125 in the test sample solution is obtained according to the working curve.

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