Preparation method and application of Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor

Abstract

The present invention provides a preparation method and application of an Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor; comprising: step 1, preparation of a ZnIn2S4 thin film; step 2, preparation of a ZnIn2S4 / MoS2 composite thin film; step 3, preparation of an Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor. The present invention also relates to the application of an Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor. The present invention efficiently combines a MoS2 layer with a ZnIn2S4 thin film to form a ZnIn2S4 / MoS2 heterojunction, effectively suppressing the recombination of photogenerated electrons and holes; wherein, the van der Waals force generated between the MoS2 layer and the ZnIn2S4 thin film helps to adsorb aptamers of serotonin, thereby improving the sensitivity and specificity of the sensor; during the process of combining the MoS2 layer with the ZnIn2S4 thin film of the present invention, the MoS2 layer improves the hydrophilicity of the ZnIn2S4 thin film, thereby realizing the detection of serotonin by the biosensor.

Description

Technical Field

[0001] The present invention belongs to the field of biosensor technology; in particular, it relates to a preparation method and application of an Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor. Background Art

[0002] Depression has become a serious social problem. As a key depression marker, serotonin holds great potential for widespread depression screening. Common serotonin detection techniques, such as fluorescence and gas chromatography, suffer from long testing times, expensive equipment, and complex procedures. Photoelectrochemical biosensors, on the other hand, offer advantages such as high sensitivity, a low detection limit, and low cost, requiring minimal equipment, making them well-suited for widespread depression screening.

[0003] ZnIn2S4, a ternary metal sulfide, possesses excellent optical properties and catalytic stability, along with advantages such as low cost, low toxicity, and ease of preparation. This overcomes the shortcomings of traditional sulfide catalysts, which are susceptible to photocorrosion. Furthermore, among ternary metal sulfides, ZnIn2S4 is the only compound with a layered structure, making it a promising material for constructing biosensors. However, the presence of numerous interfering substances in the serotonin-related testing environment, coupled with very low concentrations to be measured, places higher demands on the specificity and sensitivity of biosensors. Therefore, the ability to stably anchor biological probes on the surface of semiconductor photoelectrodes is a crucial factor. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation method and application of an Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor.

[0005] The present invention is achieved through the following technical solutions:

[0006] The present invention relates to a method for preparing an Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor, comprising the following steps:

[0007] Step 1, preparation of ZnIn2S4 thin film

[0008] (1.1) Clean a 3.3 cm × 5 cm piece of FTO, soak it in pure water, purge it with N2, and transfer it to a reactor;

[0009] (1.2) Dissolve ZnCl2, InCl3·3H2O, and CH4N2S in a mixture of pure water and anhydrous ethanol, stir well to obtain a reaction precursor solution, transfer the reaction precursor solution to a reactor containing FTO, and perform hydrothermal growth in a constant temperature forced air drying oven;

[0010] (1.3) After the reaction is completed, quickly cool the reactor to room temperature and take out the sample;

[0011] (1.4) Clean the sample and move it to a constant temperature forced air drying oven to dry it to obtain a ZnIn2S4 thin film;

[0012] Step 2, preparation of ZnIn2S4 / MoS2 composite film

[0013] (2.1) Transfer 0.0065 g of ammonium tetrathiomolybdate into 1 mL of N,N-dimethylformamide and sonicate for 30 minutes to obtain a homogeneous solution A.

[0014] (2.2) Cut the ZnIn2S4 film into 3.3 cm × 3.3 cm pieces and purge them with N2;

[0015] (2.3) Solution A was evenly deposited on the ZnIn2S4 film by spin coating and allowed to dry at room temperature;

[0016] (2.4) The sample was placed in a plasma-enhanced chemical vapor deposition tube furnace, heated to 400°C at 10°C / min under low pressure and high-purity Ar atmosphere, and kept for 1 hour. The sample was then washed with pure water and dried naturally to obtain a ZnIn2S4 / MoS2 composite film.

[0017] Step 3, Preparation of Au-ZnIn2S4 / MoS2 Photoelectrochemical Biosensor

[0018] (3.1) Using high vacuum evaporation technology, evaporate Au metal film with a thickness of 0.2 nm on the surface of ZnIn2S4 / MoS2 composite film, and clean the sample;

[0019] (3.2) Annealing at 400°C in a plasma-enhanced chemical vapor deposition tube furnace under low pressure and high-purity Ar atmosphere to obtain the Au-ZnIn2S4 / MoS2 photoanode;

[0020] (3.3) Cut the Au-ZnIn2S4 / MoS2 photoanode into 1 cm × 0.5 cm pieces, purge them with N2, and coat the aptamer probe on the surface of the Au-ZnIn2S4 / MoS2 photoanode and incubate.

[0021] (3.4) Rinse the film surface with pure water and dry it naturally to obtain the Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor.

[0022] Preferably, in (1.2), the molar concentration ratio of ZnCl2, InCl3·3H2O and CH4N2S is 1:2:4, the volume ratio of pure water and anhydrous ethanol is 90:10; the hydrothermal growth temperature is 120-180°C, and the hydrothermal growth time is 6-14h.

[0023] Preferably, in (1.4), the method for cleaning the sample is to first rinse it with pure water three times and then rinse it with anhydrous ethanol three times.

[0024] Preferably, in (1.4), the drying temperature is a constant temperature of 60° C., and the drying time is 2 to 6 hours.

[0025] Preferably, in (2.3), the spin coating speed in the spin coating technology is 1500 to 3000 rpm, and the spin coating time is 30 to 60 s.

[0026] Preferably, in (2.4), the Ar flow rate in the plasma enhanced chemical vapor deposition tube furnace is 25 to 50 sccm, and the gas pressure in the chamber is 10 to 40 Pa.

[0027] Preferably, in (3.2), the Ar flow rate in the plasma enhanced chemical vapor deposition tube furnace is 25 to 50 sccm, and the gas pressure in the chamber is 10 to 40 Pa.

[0028] Preferably, in (3.3), the aptamer probe is a DNA aptamer probe of serotonin.

[0029] Preferably, in (3.3), the incubation temperature is 4° C. and the incubation time is 12 to 14 hours.

[0030] The present invention also relates to the application of the aforementioned Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor, wherein the Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor prepared according to claim 1 is used for the detection of serotonin.

[0031] The present invention has the following advantages:

[0032] (1) The method of the present invention is to grow a uniform ZnIn2S4 thin film by hydrothermal growth, and its photoelectric performance is 2mW / cm 2 It reaches the 0.2mA level under low light intensity, leaving ample space for photoelectric response regulation for subsequent incubation of aptamers and material detection, which is beneficial to improving the sensitivity of semiconductor photoelectrochemistry.

[0033] (2) The method involved in the present invention efficiently combines the MoS2 layer with the ZnIn2S4 film to form a ZnIn2S4 / MoS2 heterojunction, which effectively inhibits the recombination of photogenerated electrons and holes. The van der Waals force generated between the MoS2 layer and the ZnIn2S4 film helps to adsorb the aptamer of serotonin, thereby improving its sensitivity and specificity; and the MoS2 layer improves the hydrophilicity of the ZnIn2S4 film, thereby realizing the detection of serotonin by the biosensor.

[0034] (3) When the Au nanolayer is fixed by the evaporation technology in the present invention, an Au-S bond is formed with the MoS2 layer on the surface of the ZnIn2S4 / MoS2 photoanode, thereby making the Au bond more firmly. This not only effectively improves the stability of the sensor, but also improves the carrier utilization efficiency, thereby effectively enhancing the photoelectric response of the sensor.

[0035] (4) The Au-S bond generated by the Au nanolayer on the surface of the Au-ZnIn2S4 / MoS2 photoelectric biosensor prepared by the present invention and the serotonin aptamer provides more binding sites for the specific probe, thereby improving the sensitivity and accuracy of the sensor and broadening the linear detection area of ​​the photoelectric biosensor.

[0036] (5) Au-ZnIn2S prepared by the method of the present invention 4 / MoS2 photoelectric biosensors have the advantages of high sensitivity and excellent specificity, and have application potential and wide expansion capabilities in fields such as early screening of depression markers. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is the detection characteristic curve of Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor for serotonin;

[0038] Figure 2 This is a diagram showing the evaluation of the detection specificity of Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor for serotonin. DETAILED DESCRIPTION

[0039] The present invention will be described in detail below with reference to specific embodiments. It should be noted that the following embodiments are only for further explanation of the present invention, but the protection scope of the present invention is not limited to the following embodiments.

[0040] Example

[0041] This embodiment relates to a method for preparing an Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor, comprising the following steps:

[0042] Step 1, preparation of ZnIn2S4 thin film

[0043] (1) Take out the FTO sample and cut it into 3.3 cm × 5 cm size. Ultrasonicate it in a solution of FTO cleaning solution: pure water = 1:9 for 10-20 minutes, then ultrasonicate it in anhydrous ethanol for 10-20 minutes, and then ultrasonicate it in pure water for 10-20 minutes. Take out the sample and purge it with N2, and move it to a 200 ml reactor;

[0044] (2) 0.1363 g ZnCl2, 0.5865 g InCl3·3H2O, and 0.3045 g CH4N2S were dissolved in a mixed solution of 90 ml pure water and 10 ml anhydrous ethanol, and stirred on a magnetic stirrer at 400 rpm for 30 minutes to obtain a reaction precursor solution. The reaction precursor solution was slowly poured into a reactor containing FTO and hydrothermally grown in a constant temperature forced air drying oven at 160°C for 7 hours;

[0045] (3) At the moment the hydrothermal reaction is completed, use heat-resistant gloves to move the reactor under water and quickly cool it down for 15 minutes. Remove the reactor liner and use tweezers to remove the sample after the liner cools naturally to room temperature.

[0046] (4) The sample was wiped with a dust-free cloth to clean the deposited material on the back of the sample, and after washing with pure water and anhydrous ethanol three times each, it was placed in a constant temperature forced air drying oven at 60°C and dried for 2 hours to obtain a ZnIn2S4 thin film.

[0047] Step 2, preparation of ZnIn2S4 / MoS2 composite film

[0048] (1) Dissolve 0.0065 g of ammonium tetrathiomolybdate in 1 ml of N,N-dimethylformamide and sonicate for 30 minutes to obtain a homogeneous solution A;

[0049] (2) Cut the ZnIn2S4 film into 3.3 cm × 3.3 cm pieces and purge them with N2;

[0050] (3) Spin coat 273 μl of uniform solution A onto a 3.3 cm × 3.3 cm ZnIn2S4 film at 2000 rpm for 50 s and allow to dry completely at room temperature.

[0051] (4) The sample was placed in the heating furnace of a plasma enhanced chemical vapor deposition tube furnace, the argon flow in the furnace was controlled at a flow rate of 30 sccm, the gas pressure was maintained at 15 Pa, the temperature was raised to 400 ° C at a rate of 10 ° C / min, and the temperature was kept at that temperature for 1 hour, washed with pure water, and dried to obtain a ZnIn2S4 / MoS2 composite film;

[0052] Step 3, Preparation of Au-ZnIn2S4 / MoS2 Photoelectrochemical Biosensor

[0053] (1) Using high vacuum evaporation coating technology, an Au metal film was evaporated on the surface of the ZnIn2S4 / MoS2 composite film. The thickness of the Au metal film was 0.2 nm, and the sample was cleaned;

[0054] (2) The sample was placed in a heating furnace of a plasma enhanced chemical vapor deposition tube furnace. Under argon flow protection, the flow rate was 30 sccm, the gas pressure was maintained at 15 Pa, and the temperature was raised to 400 ° C at a rate of 10 ° C / min and kept at this temperature for 1 hour to obtain an Au-ZnIn2S4 / MoS2 photoanode;

[0055] (3) Prepare 1 μM 5-HT aptamer probe, cut the obtained Au-ZnIn2S4 / MoS2 photoanode into 1 cm × 0.5 cm size, purge it with N2, coat the aptamer probe on the surface of Au-ZnIn2S4 / MoS2 photoanode, and incubate it in a refrigerator at 4°C for 14 h;

[0056] (4) Rinse the film surface with pure water and dry it naturally to obtain the Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor.

[0057] The performance test of the product prepared in the above embodiment is carried out as follows:

[0058] The test solutions of different concentrations were coated on the surface of the prepared Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor. After incubation at 37°C for 30 minutes, the electrode surface was fully rinsed with pure water and dried. The working electrode was used, the Pt electrode was used as the negative electrode, and the Ag / AgCl electrode was used as the reference electrode. The light intensity was 2mW / cm 2 Under the irradiation of monochromatic light with a wavelength of 365nm, the sensing detection characteristics of the series of sensors were tested by the time-current curve function of the electrochemical workstation.

[0059] Figure 1 The detection characteristic curve of Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor for serotonin can be clearly seen. Its photocurrent signal decreases significantly with the increase of serotonin concentration, which further proves that the Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor prepared in the embodiment of the present invention can detect the concentration of serotonin substance, and its sensing performance is inhibitory. The Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor prepared in the embodiment of the present invention not only detects a large photocurrent signal, the difference is suppressed from 30uA to 18uA, and shows a good linear relationship, which proves that the prepared Au-Zn ZnIn2S4 / MoS2 photoelectrochemical biosensor is very sensitive to changes in serotonin concentration. The detection line width is 10 -11 ~10 -8 g / mL, detection limit 0.31×10 -11 g / mL (S / N=3).

[0060] Figure 2In order to test the detection specificity of the prepared Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor for serotonin, the Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor of the present invention has a very obvious light response signal to serotonin, with a difference of about 0.02 mA / cm 2 However, the responses to other interference items (dopamine, tryptophan, bovine serum albumin, glucose) are very weak, much smaller than the optical response signal value of the Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor of the present invention to serotonin, which further proves that the Au-ZnIn2S4 / MoS2 photoelectric biosensor prepared by the method of the present invention has a strong detection specificity for serotonin after fixing the serotonin aptamer.

[0061] In summary, the present invention first hydrothermally grows a uniform ZnIn2S4 thin film, and forms a heterojunction that effectively combines the MoS2 nanolayer with the ZnIn2S4 thin film, inhibits the recombination of photogenerated electrons and holes, provides an effective binding site for the DNA single-stranded aptamer, and solves the non-hydrophilic defect of the ZnIn2S4 thin film. The ultra-thin Au nanolayer deposited by high-vacuum evaporation coating technology forms an effective carrier transport system, improves the photoelectrochemical performance, and further increases the binding sites of the DNA single-stranded aptamer, greatly improving the sensitivity and specificity of the sensor.

[0062] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various variations or modifications within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A method for preparing an Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor, characterized in that: The following steps are involved: Step 1, preparation of ZnIn2S4 thin film (1.1) Clean a 3.3 cm × 5 cm FTO sheet, soak it in pure water, purge it with N2, and transfer it to the reactor. (1.2) Dissolve ZnCl2, InCl3·3H2O, and CH4N2S in a mixture of pure water and anhydrous ethanol, stir well, and prepare a reaction precursor solution. Transfer the reaction precursor solution to a reactor containing FTO and perform hydrothermal growth in a constant temperature forced air drying oven. (1.3) After the reaction is completed, quickly cool the reactor to room temperature and remove the sample; (1.4) Clean the sample and move it to a constant temperature forced air drying oven to dry it to obtain a ZnIn2S4 thin film; Step 2, preparation of ZnIn2S4 / MoS2 composite film (2.1) Transfer 0.0065 g of ammonium tetrathiomolybdate into 1 mL of N,N-dimethylformamide and sonicate for 30 minutes to obtain a homogeneous solution A. (2.2) Cut the ZnIn2S4 film into 3.3 cm × 3.3 cm pieces and purge them with N2; (2.3) Spin-coat solution A onto the ZnIn2S4 film and allow to dry at room temperature. (2.4) Place the sample in a plasma-enhanced chemical vapor deposition tube furnace. Under low pressure and high-purity Ar atmosphere, heat the sample at 10°C / min to 400°C and hold for 1 hour. Rinse with pure water and dry naturally to obtain a ZnIn2S4 / MoS2 composite film. Step 3, Preparation of Au-ZnIn2S4 / MoS2 Photoelectrochemical Biosensor (3.1) Using high vacuum evaporation technology, evaporate a 0.2 nm thick Au metal film on the surface of the ZnIn2S4 / MoS2 composite film and clean the sample; (3.2) Annealing at 400 °C in a plasma-enhanced chemical vapor deposition tube furnace under low pressure and high-purity Ar atmosphere to obtain the Au-ZnIn2S4 / MoS2 photoanode; (3.3) Cut the Au-ZnIn2S4 / MoS2 photoanode into 1 cm × 0.5 cm pieces, purge them with N2, and coat the surface of the Au-ZnIn2S4 / MoS2 photoanode with an aptamer probe, which is a DNA aptamer probe for serotonin, and incubate. (3.4) Rinse the film surface with pure water and dry it naturally to obtain the Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor.

2. The method for preparing the Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor according to claim 1, wherein: In (1.2), the molar concentration ratio of ZnCl2, InCl3·3H2O and CH4N2S is 1:2:4, the volume ratio of pure water and anhydrous ethanol is 90:10; the hydrothermal growth temperature is 120-180°C, and the hydrothermal growth time is 6-14 h.

3. The method for preparing the Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor according to claim 1, wherein: In (1.4), the method for cleaning the sample is to first rinse it with pure water three times and then rinse it with anhydrous ethanol three times.

4. The method for preparing the Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor according to claim 1, wherein: In (1.4), the drying temperature is a constant temperature of 60°C, and the drying time is 2 to 6 hours.

5. The method for preparing the Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor according to claim 1, wherein: In (2.3), the spin coating speed in the spin coating technique is 1500 to 3000 rpm, and the spin coating time is 30 to 60 s.

6. The method for preparing the Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor according to claim 1, wherein: In (2.4), the Ar flow rate in the plasma enhanced chemical vapor deposition tube furnace is 25 to 50 sccm, and the gas pressure in the chamber is 10 to 40 Pa.

7. The method for preparing the Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor according to claim 1, wherein: In (3.2), the Ar flow rate in the plasma enhanced chemical vapor deposition tube furnace is 25 to 50 sccm, and the gas pressure in the chamber is 10 to 40 Pa.

8. The method for preparing the Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor according to claim 1, wherein: In (3.3), the incubation temperature is 4°C and the incubation time is 12 to 14 hours.

9. An application of an Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor, characterized in that: The Au-ZnIn2S4 / MoS2 photoelectrochemical biosensor prepared according to claim 1 is used for the detection of serotonin.

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