Preparation method and application of Faraday cage type polarity reversal photoelectrochemical sensor for detecting food-borne pathogenic bacteria
Through the Faraday cage construction model, combined with Bi2S3 and aptamer Apt, and GO@Cu2O-Apt, a Faraday cage polarity flip photoelectrochemical sensor was constructed, which solved the problem of low detection sensitivity of foodborne pathogenic bacteria and achieved high sensitivity and selective detection effects.
Patent Information
- Application Number
- CN202411555241.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-04
- Publication Date
- 2025-04-11
AI Technical Summary
The detection of foodborne pathogenic bacteria has a problem of low sensitivity, especially because of their large size and non-conductivity, which hinders the transmission of electrons between the signal probe and the electrode, resulting in the photocurrent polarity flip factor limiting the photocurrent polarity flip of the substrate modified electrode.
The Faraday cage construction model was adopted, and the Faraday cage polarity flip photoelectrochemical sensor was constructed through the combination of Bi2S3 and aptamer Apt and GO@Cu2O-Apt to realize electrode reactions with large loads of signal markers and improve detection sensitivity.
It significantly improves the sensitivity and selectivity of detecting food-borne pathogenic bacteria, can accurately detect different concentrations of food-borne pathogenic bacteria, and has good storage stability and accuracy.
Smart Images
Figure CN119804587A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a photoelectrochemical sensor, and in particular to a preparation method and application of a Faraday cage type polarity reversal photoelectrochemical sensor for detecting foodborne pathogenic bacteria. Background Art
[0002] Foodborne pathogens are a major problem in food safety, and it is of great significance to carry out sensitive, accurate and rapid detection of them. The traditional plate counting method is time-consuming and complicated, and it is difficult to meet the needs of rapid detection. Recently, many new sensor detection methods for foodborne pathogens have emerged, including: spectral methods such as colorimetry, fluorescence and surface enhanced Raman scattering; electrochemical methods such as electrochemistry, electrochemiluminescence and photoelectrochemistry; mass spectrometry; low-field nuclear magnetic resonance; etc. Among them, the input signal of the photoelectrochemical method is light and the output signal is electricity, so it has a low background signal and high sensitivity, which is unique.
[0003] The signal response modes of PEC include: signal attenuation, signal enhancement and signal reversal. In practical applications, the first two are inevitably interfered by the coexisting matrix in the sample and are prone to produce false positive or false negative signals. The photocurrent signal reversal strategy, that is, only the target will cause the reversal of the photocurrent polarity while the coexisting matrix cannot, effectively improves the detection selectivity and has received widespread attention in recent years. PEC signal reversal has recently been attempted for the detection of foodborne pathogens, but foodborne pathogens are large in size and non-conductive, which hinders the electron transfer between the signal probe and the electrode, severely weakens the photocurrent polarity reversal effect of the photocurrent polarity reversal factor on the substrate-modified electrode, and limits its detection sensitivity.
[0004] The Faraday cage sensor construction mode can effectively break through the bottleneck of electrode detection sensitivity caused by large-volume targets. This mode usually uses multifunctional bio-nanomaterials as signal units, that is, the target recognition element and the signal tag are assembled on the two-dimensional conductive nanomaterial at the same time. These materials can be assembled on the electrode surface in an adsorbed state, directly contact the electrode surface, and become part of the electrode. Not only does it greatly increase the number of signal tags, but it also ensures the efficiency of the electrochemical reaction through distance-free electron transfer, significantly improving the detection sensitivity. At present, there are no public reports at home and abroad on the use of Faraday cage polarity reversal photoelectrochemical sensors to detect foodborne pathogens. Summary of the invention
[0005] The present invention is further described in detail below with reference to the accompanying drawings.
[0006] Example 1
[0007] A preparation method and application of a Faraday cage polarity reversal photoelectrochemical sensor for detecting foodborne pathogens, which is not intended for diagnosis or treatment, and comprises the following steps:
[0008] (1) Synthesis of Bi2S3
[0009] First, 0.08-0.24 g Bi(NO3)3·5H2O was added to 20-60 mL aqueous solution containing 0.1-0.5 g thiourea. The mixture was stirred at 60°C for 20 min. The mixture was then transferred to a Teflon-lined stainless steel reactor, heated to 140-160°C and maintained for 1 h. After that, the mixture was cooled to room temperature, the product was collected by centrifugation, washed with ethanol and water, and dried at 60°C to obtain flower-like Bi2S3.
[0010] (2) Preparation of GO@Cu2O-Apt
[0011] a. Weigh 5-15 mg GO and add it to 10-30 mL water, and obtain a GO aqueous dispersion by ultrasonic dispersion. Subsequently, add 1-3 mL 0.08-0.18 mol / L Cu(NO3)2·3H2O solution to the GO dispersion, continue ultrasonication for 20 minutes, and then add 0.27-0.81 mL 0.5-2 mol / L NaOH and 1.8-4.8 mL 0.05-0.2 mol / L N2H4·H2O. After vigorous stirring for 75 minutes, collect the product and wash it several times by centrifugation with ethanol and water, and then add 2.5-7.5 mL water to obtain a GO@Cu2O dispersion.
[0012] b. Add 1-4 mL of 0.5-2 μmol / L Apt solution to 0.5-3 mL of GO@Cu2O dispersion and incubate at room temperature for 4 h. Then centrifuge to remove unbound Apt, wash with water, add 0.5-2 mL of 0.5-2 mmol / L MCH, and incubate with shaking for 1 h to block nonspecific binding sites. Collect the prepared GO@Cu2O-Apt by centrifugation, wash with water, and redisperse in Tris-HCl buffer (100 mmol / L, pH 7.4), and store at 4 °C for later use.
[0013] (3) Construction of Faraday cage polarity reversal photoelectrochemical sensor
[0014] a. Apply 10-50 μL of 2-6 mg / mL Bi2S3 aqueous dispersion to the clean ITO electrode surface, dry naturally in a dark place, and obtain Bi2S3 / ITO modified electrode. Subsequently, add 5-30 μL of 0.5-2 μmol / L Apt solution to the electrode surface, incubate at room temperature for 4 hours, and rinse with water three times. In order to block nonspecific binding sites, add 5-30 μL of 0.5-2 mmol / L MCH to the modified electrode surface, incubate at room temperature for 1 hour, and wash with water to obtain Apt / Bi2S3 / ITO, which is stored at 4°C for future use.
[0015] b. 10-30 μL of VP samples of different concentrations were added to the Apt / Bi2S3 / ITO electrode, incubated at room temperature for 1 hour, and then 10-30 μL of GO@Cu2O-Apt dispersion was added, and incubated at room temperature for 1 hour to obtain the GO@Cu2O-Apt / VP / Apt / Bi2S3 / ITO electrode. The electrode needs to be washed 3 times after each modification step. The Faraday cage polarity reversal photoelectrochemical sensor for detecting foodborne pathogens was obtained.
[0016] Furthermore, the thiol-modified aptamer Apt is 5'-SH-TCTAAAAATGGCAAAGAAACAGTGACGTCGTTGAGATACT-3'.
[0017] Furthermore, the foodborne pathogenic bacteria is Vibrio parahaemolyticus VP.
[0018] 2. A method for detecting foodborne pathogens using the above-mentioned Faraday cage polarity reversal photoelectrochemical sensor. This method is not for the purpose of diagnosis or treatment, and comprises the following steps: using the prepared Faraday cage polarity reversal photoelectrochemical sensor for detecting foodborne pathogens as a working electrode, a platinum electrode as an auxiliary electrode, and an Ag / AgCl electrode as a reference electrode, placed in a 100 mmol / L Tris-HCl buffer solution with a pH of 7.4 containing 0.1 mol / L electron donor ascorbic acid AA, and using a photoelectrochemical method to determine the corresponding reversal photocurrent intensity under different concentrations of foodborne pathogens, and obtaining the concentration of foodborne pathogens in the test solution according to the reversal photocurrent signal value.
[0019] Furthermore, the photoelectrochemical method uses 850nm near-infrared laser (1W) as the excitation light source and the applied potential is -0.1V.
[0020] Principle of the invention: The present invention is based on the Faraday cage polarity reversal construction mode to construct a fast, simple, accurate and sensitive photoelectrochemical biosensor for detecting foodborne pathogens. The Bi2S3 on the electrode binds a large number of aptamers Apt through Bi-S bonds. When foodborne pathogens are present, thanks to the high affinity and specificity of Apt on the electrode, it can quickly capture foodborne pathogens, and further specifically bind to GO@Cu2O-Apt modified with Apt to form a Faraday cage polarity reversal photoelectrochemical biosensor. The higher the concentration of foodborne pathogens, the more photocurrent polarity reversal factors introduced on the electrode surface, and the larger the flipped photocurrent signal.
[0021] Compared with the prior art, the advantages of the present invention are:
[0022] 1. High selectivity: Other common foodborne pathogens have no interference with this detection system. The reason is that the photocurrent polarity reversal is triggered by the specific binding of the target with the photocurrent polarity reversal factor modified with the aptamer, and the interfering substances can only cause the photocurrent to weaken or enhance, but cannot change the photocurrent polarity.
[0023] 2. High sensitivity: Compared with the traditional method of marking the photocurrent signal reversal factor on nanomaterials or aptamers, where the number of labels is limited, the present invention adopts a Faraday cage construction mode. The signal marker load is large and can participate in the electrode reaction. Electrons can flow freely between the electrode and the signal unit without being hindered by the huge target foodborne pathogens, thereby achieving a significant improvement in sensitivity.
[0024] 3. Universality: Simply by replacing the specific recognition aptamer, the detection of different foodborne pathogens can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 Flow chart of the Faraday cage polarity reversal photoelectrochemical sensor for detecting foodborne pathogenic bacteria VP;
[0026] Figure 2 It is the PEC signal response diagram corresponding to different concentrations of VP;
[0027] Figure 3 It is the linear relationship diagram between different VP concentrations and PEC intensity;
[0028] Figure 4 The selectivity of Faraday cage polarity reversal photoelectrochemical sensors;
[0029] Figure 5 Stability of Faraday cage polarity reversal photoelectrochemical sensor. DETAILED DESCRIPTION
[0030] The present invention is further described in detail below with reference to the accompanying drawings. 1. Specific embodiments
[0032] Example 1
[0033] A preparation method and application of a Faraday cage polarity reversal photoelectrochemical sensor for detecting foodborne pathogens, which is not intended for diagnosis or treatment, and comprises the following steps:
[0034] (1) Synthesis of Bi2S3
[0035] First, 0.16 g Bi(NO3)3·5H2O was added to 40 mL aqueous solution containing 0.25 g thiourea. The mixture was stirred at 60°C for 20 min. The mixture was then transferred to a Teflon-lined stainless steel reactor and heated to 150°C for 1 h. After that, the mixture was cooled to room temperature, and the product was collected by centrifugation, washed with ethanol and water, and dried at 60°C to obtain flower-like Bi2S3.
[0036] (2) Preparation of GO@Cu2O-Apt
[0037] a. Weigh 10 mg of GO and add it to 20 mL of water to obtain a GO aqueous dispersion by ultrasonic dispersion. Subsequently, add 1.5 mL of 0.11 mol / L Cu(NO3)2·3H2O solution to the GO dispersion, continue ultrasonication for 20 minutes, and then add 0.54 mL of 1.0 mol / L NaOH and 3.6 mL of 0.1 mol / L N2H4·H2O. After vigorous stirring for 75 minutes, collect the product and wash it several times by centrifugation with ethanol and water, and then add 5 mL of water to obtain a GO@Cu2O dispersion.
[0038] b. Add 2 mL of 1 μmol / L Apt solution to 1 mL of GO@Cu2O dispersion and incubate at room temperature for 4 h. Then centrifuge to remove unbound Apt, wash with water, add 1 mL of 1 mmol / L MCH, and incubate with shaking for 1 h to block nonspecific binding sites. Collect the prepared GO@Cu2O-Apt by centrifugation, wash with water, and redisperse in Tris-HCl buffer (100 mmol / L, pH 7.4), and store at 4 °C for later use.
[0039] (3) Construction of Faraday cage polarity reversal photoelectrochemical sensor
[0040] a. Apply 25 μL of 4 mg / mL Bi2S3 aqueous dispersion to the clean ITO electrode surface, dry naturally in a dark place, and obtain Bi2S3 / ITO modified electrode. Subsequently, add 20 μL of 1 μmol / L Apt solution to the electrode surface, incubate at room temperature for 4 hours, and rinse with water three times. In order to block nonspecific binding sites, add 20 μL of 1 mmol / L MCH to the modified electrode surface, incubate at room temperature for 1 hour, wash with water, and obtain Apt / Bi2S3 / ITO, which is stored at 4°C for future use. The sequence of the aptamer is: 5'-SH-TCTAAAAATGGCAAAGAAACAGTGACGTCGTTGAGATACT-3'.
[0041] b. 20 μL of VP samples of different concentrations were added to the Apt / Bi2S3 / ITO electrode, incubated at room temperature for 1 hour, and then 20 μL of GO@Cu2O-Apt dispersion was added, and incubated at room temperature for 1 hour to obtain the GO@Cu2O-Apt / VP / Apt / Bi2S3 / ITO electrode. The electrode needs to be washed 3 times after each modification step. The Faraday cage polarity reversal photoelectrochemical sensor for detecting foodborne pathogens was obtained.
[0042] Example 2
[0043] The same as the above-mentioned embodiment 1, the difference is:
[0044] (1) Synthesis of Bi2S3
[0045] First, 0.16 g Bi(NO3)3·5H2O was added to 30 mL aqueous solution containing 0.2 g thiourea. The mixture was stirred at 60°C for 20 min. The mixture was then transferred to a Teflon-lined stainless steel reactor and heated to 140°C for 1 h. After that, the mixture was cooled to room temperature, and the product was collected by centrifugation, washed with ethanol and water, and dried at 60°C to obtain flower-like Bi2S3.
[0046] (2) Preparation of GO@Cu2O-Apt
[0047] a. Weigh 12 mg of GO and add it to 16 mL of water to obtain a GO aqueous dispersion by ultrasonic dispersion. Subsequently, add 2.6 mL of 0.12 mol / L Cu(NO3)2·3H2O solution to the GO dispersion, continue ultrasonication for 20 minutes, and then add 0.54 mL of 0.15 mol / L NaOH and 2.4 mL of 0.15 mol / L N2H4·H2O. After vigorous stirring for 75 minutes, collect the product and wash it several times by centrifugation with ethanol and water, and then add 6 mL of water to obtain a GO@Cu2O dispersion.
[0048] b. Add 2 mL of 1 μmol / L Apt solution to 2 mL of GO@Cu2O dispersion and incubate at room temperature for 4 h. Then centrifuge to remove unbound Apt, wash with water, add 0.8 mL of 0.8 mmol / L MCH, and incubate with shaking for 1 h to block nonspecific binding sites. The prepared GO@Cu2O-Apt was collected by centrifugation, washed with water, and redispersed in Tris-HCl buffer (100 mmol / L, pH 7.4), and stored at 4 °C for later use.
[0049] (3) Construction of Faraday cage polarity reversal photoelectrochemical sensor
[0050] a. Apply 20 μL of 4 mg / mL Bi2S3 aqueous dispersion to the clean ITO electrode surface, dry naturally in a dark place, and obtain Bi2S3 / ITO modified electrode. Subsequently, add 18 μL of 1.5 μmol / L Apt solution to the electrode surface, incubate at room temperature for 4 hours, and rinse with water three times. In order to block nonspecific binding sites, add 20 μL of 1.2 mmol / L MCH to the modified electrode surface, incubate at room temperature for 1 hour, and wash with water to obtain Apt / Bi2S3 / ITO, which is stored at 4°C for future use.
[0051] b. 14 μL of VP samples of different concentrations were added to the Apt / Bi2S3 / ITO electrode, incubated at room temperature for 1 hour, and then 16 μL of GO@Cu2O-Apt dispersion was added, and incubated at room temperature for 1 hour to obtain the GO@Cu2O-Apt / VP / Apt / Bi2S3 / ITO electrode. The electrode needs to be washed 3 times after each modification step. The Faraday cage polarity reversal photoelectrochemical sensor for detecting foodborne pathogens was obtained.
[0052] Example 3
[0053] The same as the above-mentioned embodiment 1, the difference is:
[0054] (1) Synthesis of Bi2S3
[0055] First, 0.22 g Bi(NO3)3·5H2O was added to 40 mL aqueous solution containing 0.4 g thiourea. The mixture was stirred at 60°C for 20 min. The mixture was then transferred to a Teflon-lined stainless steel reactor and heated to 160°C for 1 h. After that, the mixture was cooled to room temperature, and the product was collected by centrifugation, washed with ethanol and water, and dried at 60°C to obtain flower-like Bi2S3.
[0056] (2) Preparation of GO@Cu2O-Apt
[0057] a. Weigh 14 mg of GO and add it to 24 mL of water to obtain a GO aqueous dispersion by ultrasonic dispersion. Subsequently, add 1.3 mL of 0.15 mol / L Cu(NO3)2·3H2O solution to the GO dispersion, continue ultrasonication for 20 minutes, and then add 0.81 mL of 0.18 mol / L NaOH and 3.6 mL of 0.09 mol / L N2H4·H2O. After vigorous stirring for 75 minutes, collect the product and wash it several times by centrifugation with ethanol and water, and then add 5.5 mL of water to obtain a GO@Cu2O dispersion.
[0058] b. Add 1 mL of 2 μmol / L Apt solution to 1 mL of GO@Cu2O dispersion and incubate at room temperature for 4 h. Then centrifuge to remove unbound Apt, wash with water, add 1 mL of 1 mmol / L MCH, and incubate with shaking for 1 h to block nonspecific binding sites. Collect the prepared GO@Cu2O-Apt by centrifugation, wash with water, and redisperse in Tris-HCl buffer (100 mmol / L, pH 7.4), and store at 4 °C for later use.
[0059] (3) Construction of Faraday cage polarity reversal photoelectrochemical sensor
[0060] a. Apply 20 μL of 3 mg / mL Bi2S3 aqueous dispersion to the clean ITO electrode surface, dry naturally in a dark place, and obtain Bi2S3 / ITO modified electrode. Subsequently, add 15 μL of 2 μmol / L Apt solution to the electrode surface, incubate at room temperature for 4 hours, and rinse with water three times. In order to block nonspecific binding sites, add 15 μL of 2 mmol / L MCH to the modified electrode surface, incubate at room temperature for 1 hour, and wash with water to obtain Apt / Bi2S3 / ITO, which is stored at 4°C for future use.
[0061] b. 16 μL of VP samples of different concentrations were added to the Apt / Bi2S3 / ITO electrode, incubated at room temperature for 1 hour, and then 18 μL of GO@Cu2O-Apt dispersion was added, and incubated at room temperature for 1 hour to obtain the GO@Cu2O-Apt / VP / Apt / Bi2S3 / ITO electrode. The electrode needs to be washed 3 times after each modification step. The Faraday cage polarity reversal photoelectrochemical sensor for detecting foodborne pathogens was obtained. Specific embodiment 2
[0063] The Faraday cage polarity reversal photoelectrochemical sensor for detecting foodborne pathogens prepared in the above specific embodiment 1 is used as the working electrode, the platinum electrode is used as the auxiliary electrode, and the Ag / AgCl electrode is used as the reference electrode. It is placed in a 100 mmol / L Tris-HCl buffer solution with a pH of 7.4 containing 0.1 mol / L electron donor ascorbic acid AA, and an applied potential of -0.1 V is used to measure the corresponding reversal photocurrent intensity under different concentrations of foodborne pathogens VP conditions, and the concentration of foodborne pathogens in the test solution is obtained according to the reversal photocurrent signal value.
[0064] like Figure 2 As shown, the flipped photocurrent intensity increases with the increase of VP concentration.
[0065] like Figure 3 As shown, in 1~1.0×10 6 In the CFU / mL range, the logarithm of the flip photocurrent intensity (I) and the VP concentration (C) showed a good linear relationship. The linear regression equation was I (nA) = -152.9lgC-18.3, and the square correlation coefficient R 2 =0.994, and the limit of detection (LOD) was approximately 1 CFU / mL. Specific embodiment three
[0067] like Figure 4 As shown, the sensor prepared by the specific embodiment 1 was used to measure the blank, 1.0×10 6 CFU / mL of Vibrio vulnificus (VV), Staphylococcus aureus (SA), and Escherichia coli (E. coli), and 1.0×10 3 CFU / mL VP and 1.0×10 6 The selectivity of the sensor for VP detection was studied by mixing other pathogens with VP and CFU / mL. Compared with the detection signals of VP and other pathogen mixtures including VP, although the concentration was 1000 times higher than VP, the PEC signals of other pathogens were close to the blank group signal (showing obvious anode photocurrent), and the PEC signal of other pathogen mixtures including VP was basically consistent with the VP signal, indicating that the sensing platform has high selectivity in detecting targets in complex samples. Specific embodiment 4
[0069] The storage stability of the sensor was further investigated. The prepared photoelectrochemical sensor was stored in a 4°C constant temperature box. Figure 5 As shown, the photocurrent after 3 weeks still retained 92.6% of the initial value, indicating that the constructed PEC sensor has good storage stability. Specific embodiment five
[0071] The accuracy and precision of the sensor were evaluated by the standard addition method. As shown in Table 1,
[0072] Table 1 Detection results of VP of the lower sample after treatment (x±s, n=5).
[0073] sample Addition amount (CFU / mL) Detection (CFU / mL) Recovery rate (%) RSD(%) 1 <![CDATA[1.0×10 2 ]]> <![CDATA[(1.022±0.025)×10 2 ]]> 102.2 2.4 2 <![CDATA[1.0×10 3 ]]> <![CDATA[(0.991±0.032)×10 3 ]]> 99.1 3.2 3 <![CDATA[1.0×10 4 ]]> <![CDATA[(0.983±0.019)×10 4 ]]> 98.3 1.9 4 <![CDATA[1.0×10 5 ]]> <![CDATA[(1.014±0.023)×10 5 ]]> 101.4 2.3
[0074] As shown in Table 1, the standard addition method was used to detect different concentrations of VP in the treated shrimp samples, with recoveries ranging from 98.3% to 102.2% and RSDs ranging from 1.9% to 3.2%, indicating that the PEC biosensor has good accuracy and precision.
[0075] The above description is not intended to limit the present invention, and the present invention is not limited to the above examples. Any changes, modifications, additions or substitutions made by a person skilled in the art within the spirit and scope of the present invention shall also fall within the protection scope of the present invention.
Claims
1. A method for preparing a Faraday cage polarity reversal photoelectrochemical sensor for detecting foodborne pathogens, characterized in that The following steps are involved: (1) Synthesis of Bi2S3 First, 0.08-0.24 g Bi(NO3)3·5H2O was added to 20-60 mL aqueous solution containing 0.1-0.5 g thiourea. The mixture was stirred at 60°C for 20 min. The mixture was then transferred to a Teflon-lined stainless steel reactor, heated to 140-160°C and maintained for 1 h. After that, the mixture was cooled to room temperature, the product was collected by centrifugation, washed with ethanol and water, and dried at 60°C to obtain flower-like Bi2S3. (2) Preparation of GO@Cu2O-Apt a. Weigh 5-15 mg GO and add it to 10-30 mL water, and obtain a GO aqueous dispersion by ultrasonic dispersion. Subsequently, add 1-3 mL 0.08-0.18 mol / L Cu(NO3)2·3H2O solution to the GO dispersion, continue ultrasonication for 20 minutes, and then add 0.27-0.81 mL 0.5-2 mol / L NaOH and 1.8-4.8 mL 0.05-0.2 mol / L N2H4·H2O. After vigorous stirring for 75 minutes, collect the product and wash it several times by centrifugation with ethanol and water, and then add 2.5-7.5 mL water to obtain a GO@Cu2O dispersion. b. Add 1-4 mL of 0.5-2 μmol / L Apt solution to 0.5-3 mL of GO@Cu2O dispersion and incubate at room temperature for 4 h. Then centrifuge to remove unbound Apt, wash with water, add 0.5-2 mL of 0.5-2 mmol / L MCH, and incubate with shaking for 1 h to block nonspecific binding sites. Collect the prepared GO@Cu2O-Apt by centrifugation, wash with water, and redisperse in Tris-HCl buffer (100 mmol / L, pH 7.4), and store at 4 °C for later use. (3) Construction of Faraday cage polarity reversal photoelectrochemical sensor a. Apply 10-50 μL of 2-6 mg / mL Bi2S3 aqueous dispersion to the clean ITO electrode surface, dry naturally in a dark place, and obtain Bi2S3 / ITO modified electrode. Subsequently, add 5-30 μL of 0.5-2 μmol / L Apt solution to the electrode surface, incubate at room temperature for 4 hours, and rinse with water three times. In order to block nonspecific binding sites, add 5-30 μL of 0.5-2 mmol / L MCH to the modified electrode surface, incubate at room temperature for 1 hour, and wash with water to obtain Apt / Bi2S3 / ITO, which is stored at 4°C for future use. b. 10-30 μL of VP samples of different concentrations were added to the Apt / Bi2S3 / ITO electrode, incubated at room temperature for 1 hour, and then 10-30 μL of GO@Cu2O-Apt dispersion was added, and incubated at room temperature for 1 hour to obtain the GO@Cu2O-Apt / VP / Apt / Bi2S3 / ITO electrode. The electrode needs to be washed 3 times after each modification step. The Faraday cage polarity reversal photoelectrochemical sensor for detecting foodborne pathogens was obtained.
2. The preparation method and application of a Faraday cage type polarity reversal photoelectrochemical sensor for detecting foodborne pathogens according to claim 1, characterized in that: The thiol-modified aptamer Apt is 5'-SH-TCTAAAAATGGCAAAGAAACAGTGACGTCGTTGAGATACT-3'.
3. The preparation method and application of a Faraday cage type polarity reversal photoelectrochemical sensor for detecting foodborne pathogens according to claim 1, characterized in that: The foodborne pathogenic bacteria is Vibrio parahaemolyticus.
4. A method for detecting foodborne pathogens using a Faraday cage polarity reversal photoelectrochemical sensor prepared by the preparation method of any one of claims 1 to 3, wherein the method is not for the purpose of diagnosis or treatment, and is characterized in that The following steps are involved: The prepared Faraday cage polarity reversal photoelectrochemical sensor for detecting foodborne pathogens was used as the working electrode, the platinum electrode as the auxiliary electrode, and the Ag / AgCl electrode as the reference electrode. The sensor was placed in a 100 mmol / L Tris-HCl buffer solution with a pH of 7.4 and containing 0.1 mol / L electron donor ascorbic acid AA. The photoelectrochemical method was used to determine the corresponding reversal photocurrent intensity under different concentrations of foodborne pathogens, and the concentration of the foodborne pathogens in the test solution was obtained according to the reversal photocurrent signal value.
5. A method for detecting foodborne pathogens using a Faraday cage polarity reversal photoelectric chemical sensor according to claim 4, characterized in that The photoelectrochemical method uses 850nm near-infrared laser (1W) as the excitation light source and applies a potential of -0.1V.