Photoelectrochemical aptamer sensor and preparation method and application thereof

Abstract

The application relates to a photoelectrochemical aptamer sensor and a preparation method and application thereof, the photoelectrochemical aptamer sensor comprising a photosensitive material and an aptamer, and the photosensitive material is CdS@NiMoS. The photosensitive material adopted by the photoelectrochemical aptamer sensor has a higher specific surface area and a high photoconversion efficiency, and can have excellent photocurrent in photoelectrochemical testing; the application has the advantages of low background current, rapid response, high sensitivity, low detection line and the like, and has a wide development prospect in small molecule detection method research and development.

Description

Technical Field

[0001] This invention belongs to the field of antibiotic detection, and specifically relates to a photoelectrochemical aptamer sensor, its preparation method, and its application. Background Technology

[0002] Antibiotics are one of the greatest inventions in human history. They are defined as secondary metabolites of microorganisms, or compounds that possess antibacterial or bactericidal properties after artificial synthesis or semi-synthesis. The invention of antibiotics has played a crucial role in treating bacterial diseases. However, long-term use of antibiotics can lead to decreased or even absent bacterial sensitivity, as well as a series of adverse reactions such as liver and kidney damage, which can be life-threatening in severe cases. In recent years, antibiotic abuse has occurred in various fields, including livestock and aquaculture, industry, and medicine. Antibiotic levels in wastewater are seriously exceeding standards, and sewage treatment plants cannot completely remove all antibiotics. Therefore, effectively improving antibiotic detection levels and implementing targeted scientific management has become an urgent problem to be solved.

[0003] Existing antibiotic detection methods, including liquid chromatography-mass spectrometry (LC-MS), gas chromatography-mass spectrometry (GC-MS), capillary electrophoresis, and immunoassay, offer high sensitivity and specificity. However, they are limited by time and space constraints, presenting numerous unresolved problems and challenges. For example, the enrichment time is long, and the consumption of large amounts of organic reagents is environmentally harmful. Furthermore, the detection process is costly, cumbersome, and lacks portability, and false positives are common. Therefore, developing highly specific and portable miniaturized antibiotic detection sensors is a crucial direction for addressing antibiotic overuse. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a photoelectrochemical aptamer sensor, its preparation method and application, which has the advantages of low background current, fast response, high sensitivity and low detection limit, and has broad development prospects in the research and development of small molecule detection methods.

[0005] This invention provides a photoelectrochemical aptamer sensor, the sensor comprising a photosensitive material and an aptamer, wherein the photosensitive material is CdS@NiMoS.

[0006] Preferably, the proportion of CdS in the photosensitive material is 20-30 wt%, and Ni is... 3+ The proportion of Mg2+ is 10-20 wt%, and the proportion of MoS2 is 60-70 wt%.

[0007] Preferably, the morphology of the photosensitive material is nanorods, nanowires, or nanosheets.

[0008] Preferably, the aptamer is an antibiotic aptamer.

[0009] Preferably, the antibiotic aptamer is a chloramphenicol aptamer.

[0010] This invention also provides a method for preparing a photoelectrochemical aptamer sensor, comprising the following steps:

[0011] (1) Clean the sensor substrate material;

[0012] (2) Take CdS@NiMoS, ion carrier and Nafion, sonicate and stir to obtain a mixed solution; perform dual-electrode electroplating on the sensor substrate material with the mixed solution, dry to obtain CdS@NiMoS chip;

[0013] (3) Dilute the antibiotic aptamer concentration to 0.1-0.5 μM to obtain the aptamer dilution solution; drop the aptamer dilution solution onto the CdS@NiMoS chip and incubate to obtain the aptamer-CdS@NiMoS chip; then drop the antibiotic onto the chip and continue incubation to obtain the antibiotic-aptamer-CdS@NiMoS chip, i.e., the photoelectrochemical aptamer sensor.

[0014] Preferably, the sensor substrate material in step (1) is ITO glass.

[0015] Preferably, the cleaning in step (1) is performed using ethanol / NaOH, acetone, and deionized water, respectively.

[0016] Preferably, the ion carrier in step (2) is elemental iodine.

[0017] Preferably, the mass-to-volume ratio of CdS@NiMoS, ion carrier, and Nafion in step (2) is 1 mg: 2-4 mg: 3-5 mL.

[0018] Preferably, the Nafion concentration in step (2) is 1-2 mg / 100 μL.

[0019] Preferably, the dual-electrode electroplating voltage in step (2) is 10-20V.

[0020] Preferably, the drying temperature in step (2) is 100-120℃ and the drying time is 30-40min.

[0021] Preferably, the incubation time in step (3) is 6h-8h.

[0022] This invention also provides an application of a photoelectrochemical aptamer sensor in antibiotic detection.

[0023] The photoelectrochemical (PEC) method employed in this invention is a method that utilizes the energy accumulated during molecular transitions after a substance is excited by light to drive an electrode reaction. Photoelectric materials are an important component of PEC detection; photosensitive materials, due to their unique and excellent optical and electrical properties, have been widely used in the energy and environmental fields. The aptamer sensor detects chloramphenicol by detecting the increase in photocurrent caused by a specific recognition reaction between chloramphenicol and a specific aptamer.

[0024] Beneficial effects

[0025] (1) The photosensitive material used in the photoelectrochemical aptamer sensor of the present invention has MoS2 nanosheets and transition metal Ni wrapped in a spiral shape on the outer layer of CdS nanorods, which has a high specific surface area and high light conversion efficiency, and can have excellent photocurrent in photoelectrochemical testing; the photosensitive material is simple to synthesize, easy to prepare, and has low process cost.

[0026] (2) This invention uses ITO glass as a conductive substrate and electroplats photosensitive material onto the ITO glass to form a thin film. ITO glass has excellent conductivity and can conduct current at low resistance. It has high transmittance in the visible light range, which allows it to be used as a transparent conductive layer without affecting optical performance. ITO conductive glass has good corrosion resistance and can resist the erosion of some chemicals and the environment, thus improving the stability and lifespan of the material.

[0027] (3) The aptamers used in this invention are chemically stable, easy to obtain, simple to prepare, and relatively inexpensive to store. Therefore, aptamer detection has stronger antibiotic specificity and can achieve high specificity and stability detection of chloramphenicol.

[0028] (4) This invention uses electroplating to prepare CdS@NiMoS chips, which improves the preparation efficiency and ensures the consistency of the coating. The simultaneous preparation using three electrochemical workstations increases the preparation speed from one chip every 10 minutes in the early stage to nine chips.

[0029] (5) The photoelectrochemical aptamer sensor of the present invention has the advantages of low background current, fast response, high sensitivity and low detection line, and has broad development prospects in the research and development of small molecule detection methods. Attached Figure Description

[0030] Figure 1 This is a flowchart of the detection process of the present invention.

[0031] Figure 2 A represents the photocurrent response of the sensor of the present invention under different concentrations of chloramphenicol (AE in the figure refers to chloramphenicol concentrations of 0.1 μM, 0.5 μM, 1 μM, 1.5 μM, and 2 μM, respectively). Figure 2B represents the linear relationship between photocurrent and chloramphenicol concentration. Figure 3 A is a schematic diagram of the sensor of the present invention prepared by electroplating; Figure 3 B is the photocurrent response CHOP diagram for different film formation methods. Detailed Implementation

[0032] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0033] Example 1

[0034] I. Synthesis of CdS@NiMoS Nanorods

[0035] Preparation of the precursor: Dissolve 4.6275 g of Cd(NO3)2-4H2O (n = 0.015 mol) in 60 mL of deionized water, and bring the volume to a 100 mL beaker. Sonicate for 10 min. Dissolve 6.7590 g of Na(DDTC) (n = 0.03 mol) in 45 mL of deionized water, and bring the volume to a 100 mL beaker. Sonicate for 10 min. Slowly add the Na(DDTC) solution to the Cd(NO3)2-4H2O solution and stir for 10 min to precipitate Cd(DDTC)2 (theoretically 0.015 mol). Wash the Cd(DDTC)2 precipitate once with distilled water, three times with ethanol, filter, and then vacuum dry and collect.

[0036] Preparation of CdS nanorods: 2g of Cd(DDTC)₂ was placed in a 100mL polytetrafluoroethylene reactor, and 70mL of ethylenediamine was added. The mixture was then reacted in an oven at 180℃ for 24h. The product was washed once with deionized water and three times with ethanol. After suction filtration, it was vacuum dried at 60℃ for 5h.

[0037] Preparation of CdS@NiMoS nanorod powder: CdS nanorods were dispersed in beaker A with deionized water. In beaker B, 3.6 mg NaMoO4-2H2O, 15 mg CN2H4S, and 8.4 mg Ni(NO3)2-6H2O were added, followed by deionized water. Beakers A and B were sonicated for 10 min. Beaker B was then transferred to beaker A and stirred for 20 min. The mixture was transferred to a 50 mL reactor and reacted at 200 °C for 24 h. The resulting photosensitive material was washed once with deionized water and three times with anhydrous ethanol. After filtration, it was vacuum dried at 60 °C for 5 h.

[0038] II. Fabrication of CdS@NiMoS photoelectrochemical aptamer sensors

[0039] The ITO glass was cleaned once each with ethanol / NaOH, acetone, and deionized water for 30 min each time; Nafion was diluted to 1 mg / 100 μL. 10 mg CdS@NiMoS nanorods, 20 mg iodine, and 30 mL Nafion were added and sonicated for 20 min, followed by stirring for 20 min. Dual-electrode electroplating was performed at 10 V, followed by drying in a 120 °C oven for 30 min. The chloramphenicol aptamer was diluted to 0.3 μM using a DNA buffer prepared with 10 mM Tris-HCl and 1 mM EDTA. 50 μL of the aptamer dilution was drop-coated onto the material and incubated at 99% humidity for 6 h to prepare the aptamer-CdS@NiMoS chip. Chloramphenicol was then drop-coated onto the chip and incubated for 6 h to prepare the chloramphenicol-aptamer-CdS@NiMoS chip.

[0040] III. Photoelectrochemical Testing of CdS@NiMoS Photoelectrochemical Adaptor Sensor

[0041] Photoelectrochemical tests were performed using a Zahner electrochemical workstation (Germany). The test light source was a 500W UV-Xenon lamp with an operating voltage of -0.25V. The tested concentration range was 0.1–2 μM to obtain linear curves within this range. Nyquist electrochemical impedance spectroscopy was used to monitor impedance changes at each operational step, thereby monitoring the entire experimental process. The detection frequency range was 0.1–3.9 × 10⁻⁶. 6 Hz.

[0042] Figure 2 A represents the photocurrent response of the CdS@NiMoS photoelectrochemical aptamer sensor under different concentrations of chloramphenicol. For example... Figure 2 As shown in Figure B, the current and concentration exhibit a linear relationship in the range of 0.1-2 μM, with a linear correlation coefficient of 0.9987.

[0043] like Figure 3 As shown in Figure B, comparing the photocurrent response CHOP diagrams of CdS@NiMoS photoelectrochemical aptamer sensors prepared by four film deposition methods, it can be seen that the photocurrent magnitude is: electroplating method > Nafion drop coating method > ethanol drop coating method > PVDF method.

Claims

1. A photoelectrochemical aptamer sensor, the sensor comprising a photosensitive material and an aptamer, characterized in that: The photosensitive material is CdS@NiMoS; the preparation method includes the following steps: (1) Clean the sensor substrate material; (2) Take CdS@NiMoS, ion carrier and Nafion, sonicate and stir to obtain a mixed solution; perform dual-electrode electroplating on the sensor substrate material with the mixed solution, dry to obtain CdS@NiMoS chip; (3) Dilute the antibiotic aptamer concentration to 0.1-0.5 μM to obtain the aptamer dilution solution; drop the aptamer dilution solution onto the CdS@NiMoS chip and incubate to obtain the aptamer-CdS@NiMoS chip; then drop the antibiotic onto the chip and continue incubation to obtain the antibiotic-aptamer-CdS@NiMoS chip, i.e., the photoelectrochemical aptamer sensor.

2. The photoelectrochemical aptamer sensor according to claim 1, characterized in that: The photosensitive material contains 20-30 wt% CdS and Ni. 3+ The proportion of Mg2+ is 10-20 wt%, and the proportion of MoS2 is 60-70 wt%.

3. The photoelectrochemical aptamer sensor according to claim 1, characterized in that: The morphology of the photosensitive material is nanorods, nanowires, or nanosheets.

4. The photoelectrochemical aptamer sensor according to claim 1, characterized in that: The aptamer is an antibiotic aptamer.

5. The photoelectrochemical aptamer sensor according to claim 4, characterized in that: The antibiotic aptamer is a chloramphenicol aptamer.

6. A method for preparing a photoelectrochemical aptamer sensor, comprising the following steps: (1) Clean the sensor substrate material; (2) Take CdS@NiMoS, ion carrier and Nafion, sonicate and stir to obtain a mixed solution; perform dual-electrode electroplating on the sensor substrate material with the mixed solution, dry to obtain CdS@NiMoS chip; (3) Dilute the antibiotic aptamer concentration to 0.1-0.5 μM to obtain the aptamer dilution solution; drop the aptamer dilution solution onto the CdS@NiMoS chip and incubate to obtain the aptamer-CdS@NiMoS chip; then drop the antibiotic onto the chip and continue incubation to obtain the antibiotic-aptamer-CdS@NiMoS chip, i.e., the photoelectrochemical aptamer sensor.

7. The preparation method according to claim 6, characterized in that: The sensor substrate material in step (1) is ITO glass.

8. The preparation method according to claim 6, characterized in that: The ion carrier in step (2) is elemental iodine.

9. The preparation method according to claim 6, characterized in that: The mass-to-volume ratio of CdS@NiMoS, ion carrier, and Nafion in step (2) is 1 mg: 2-4 mg: 3-5 mL.

10. The application of the photoelectrochemical aptamer sensor as described in claim 1 in antibiotic detection.

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