Preparation method of organic photoelectrochemical transistor sensing platform for detecting microcystic toxins

Abstract

The invention provides a preparation method of an organic photoelectrochemical transistor sensing platform for detecting microcystic toxins, which comprises the following steps: preparing a polydopamine nanosphere through a dopamine hydrochloride self-assembly reaction, and carrying out modification of a microcystic toxin second antibody and sealing treatment of bovine serum albumin to obtain the organic photoelectrochemical transistor sensing platform for detecting the microcystic toxins. According to the method, a microcystic toxin detection platform with high sensitivity and good selectivity is constructed by utilizing the specific binding capacity of the polydopamine nanospheres and the high sensitivity characteristic of the organic photoelectrochemical transistor; a new technical means is provided for the fields of environment monitoring, food detection and the like, the prepared organic photoelectrochemical transistor sensing platform has good selectivity and stability on microcystic toxins, and the detection limit is 18 pg / mL.

Description

Technical Field

[0001] This invention relates to a method for preparing an organic photoelectrochemical transistor sensing platform for detecting microcystin, and relates to organic photoelectrochemical transistors, nanomaterial preparation, and related technologies for microcystin detection. Specifically, this invention belongs to the interdisciplinary application of materials science, biotechnology, and environmental monitoring. Background Technology

[0002] Microcystins are a class of secondary metabolites produced by cyanobacteria such as Microcystis. They are highly hepatotoxic, neurotoxic, and carcinogenic. They are widely present in polluted water bodies and pose a serious threat to the environment, ecosystems, and human health. Therefore, developing sensitive, rapid, and selective methods for detecting microcystins is of great practical significance. Currently, the main methods for detecting microcystins include high-performance liquid chromatography (HPLC), enzyme-linked immunosorbent assay (ELISA), fluorescence spectroscopy, and electrochemical sensors. Although traditional electrochemical sensors have the advantages of low cost and portability, their sensitivity and selectivity still need to be improved.

[0003] In recent years, photoelectrochemical transistors have gradually become a research hotspot in the field of biosensors due to their advantages such as high sensitivity, fast response and easy integration. However, existing biosensors based on photoelectrochemical transistors still have certain limitations in terms of material selection, signal amplification capability and fabrication process. For example, traditional optoelectronic materials have weak specific recognition ability for target molecules and low signal amplification efficiency, resulting in insufficient detection sensitivity. In addition, the fabrication process of the sensors is complex, making it difficult to achieve large-scale production and practical application.

[0004] To address the aforementioned issues, this invention proposes a microcystin detection platform based on organic photoelectrochemical transistors. By optimizing the preparation process of photoelectric materials, introducing polydopamine nanospheres as signal amplification materials, and combining the specific recognition function of antibodies, the sensitivity and selectivity of the sensor are significantly improved. This technology not only enables rapid and sensitive detection of microcystins but also has the advantages of simple preparation process, low cost, and ease of large-scale production, providing a novel detection method for environmental monitoring and food safety. Summary of the Invention

[0005] One of the objectives of this invention is to utilize CuIn2S4 as a photoactive material in the organic photoelectrochemical transistor sensing platform of this invention. CuIn2S4 provides excellent photocurrent response and a large number of active sites, which facilitates the loading of capture antibodies.

[0006] The second objective of this invention is to improve the separation efficiency of photogenerated electron-hole pairs through the optimized preparation process of CuIn2S4 material, thereby solving the problem of short carrier lifetime caused by carrier recombination.

[0007] The third objective of this invention is to construct a sensing platform with polydopamine nanospheres, which achieves signal amplification and, by utilizing their specific binding ability, synergizes with CuIn2S4 material to further enhance detection sensitivity.

[0008] The fourth objective of this invention is that the sensing platform based on organic photoelectrochemical transistors exhibits good selectivity and stability for microcystin toxins and high sensitivity for the target analyte, thus meeting the needs of practical applications.

[0009] The technical solution of this invention is as follows: 1. A method for preparing an organic photoelectrochemical transistor sensing platform for detecting microcystin, characterized by comprising the following steps: (1) Preparation of polydopamine nanosphere composite material linked to the second antibody Weigh 50-60 mg of dopamine hydrochloride and 0.1-0.2 g of copper chloride, dissolve them in 80-90 mL of deionized water, and then sonicate for 5-10 minutes. Transfer the resulting solution to a constant temperature stirrer and stir continuously at 70-80℃ for 4-5 hours. After the reaction is complete, wash the product with methanol and deionized water by centrifugation until neutral, and dry the product at 40-50℃ overnight. The dried nanomaterials were dispersed in 5 mL of pH 7.25 phosphate buffer (10-20 μg / mL microcystin secondary antibody was added, and the mixture was shaken at room temperature for 0.5 hours, then 2-3% bovine serum albumin solution was slowly added to block the non-specific binding sites on the surface of the material, and the mixture was shaken vigorously for 1 hour before centrifugation and washing. Finally, the product was dispersed in 5 mL of pH 7.25 phosphate buffer and stored at 4°C for later use. (2) Fabrication of organic photoelectrochemical transistor sensing platform 1) Cut and pretreat indium tin oxide conductive glass to obtain the required ITO electrodes; 2) Drop 100-120 μL of CuIn2S4 photoelectric material with a concentration of 8-10 mg / mL onto the ITO electrode, and then calcine it in a muffle furnace at 150-200 ℃ for 2-3 hours to ensure a tighter bond between the photoelectric material and the electrode; 3) Add 5-6 μL of 0.5-0.6 mol / L mercaptoacetic acid to the CuIn2S electrode and incubate for 2-3 hours. Then, add 4-6 μL of 15-20 μg / mL microcystin primary antibody, 2% bovine serum albumin, and different concentrations of microcystin to the electrode and let them stand at 37 °C for 30 minutes to fix them onto the modified electrode. 4) 10-15 μL of the prepared second antibody-linked polydopamine nanospheres were left to stand at 4 °C for 1 h and then immobilized on the photoelectric material-modified electrode by specifically binding to microcystin. 5) Place the photoelectric modified electrode and organic transistor under the workstation for signal testing; 2. The method for preparing an organic photoelectrochemical transistor sensing platform for detecting microcystin as described in claim 1, characterized in that the polydopamine nanospheres are prepared by the following steps: Weigh 50-60 mg of dopamine hydrochloride and 0.1-0.2 g of copper chloride, dissolve them in 80-90 mL of deionized water, and then sonicate for 5-10 minutes. Transfer the resulting solution to a constant temperature stirrer and stir continuously at 70-80℃ for 4-5 hours. After the reaction is complete, wash the product with methanol and deionized water by centrifugation until neutral, and dry the product at 40-50℃ overnight. The dried nanomaterials were dispersed in 5 mL of pH 7.25 phosphate buffer, and 10-20 μg / mL microcystin secondary antibody was added. After shaking at room temperature for 0.5 hours, 2-3% bovine serum albumin solution was slowly added to block the non-specific binding sites on the surface of the material. After vigorous shaking for 1 hour, the product was centrifuged and washed. Finally, the product was dispersed in 5 mL of pH 7.25 phosphate buffer and stored at 4°C for later use. 3. The method for preparing an organic photoelectrochemical transistor sensing platform for detecting microcystin as described in claim 1, characterized in that the photoelectrochemical material CuIn2S4 is prepared by the following steps: Preparation of CuIn2S4 material: First, 0.7-0.9 g of copper nitrate and 0.4-0.5 g of indium nitrate were dissolved in 20-25 mL of deionized water and stirred under magnetic stirring for 10-15 minutes. Then, the copper nitrate and indium nitrate solutions were mixed and stirred thoroughly. The mixed solution was transferred to a reaction vessel and subjected to hydrothermal reaction at 140-150℃ for 18-20 hours. After the reaction was completed, the mixture was cooled to room temperature, the precipitate was collected by centrifugation, and washed several times with deionized water. The washed precipitate was dried at 70-80℃ for 12 hours, and then calcined at 200-230℃ for 20-30 minutes. Finally, after cooling to room temperature, the solid powder was ground to obtain CuIn2S4 nanoparticles. 4. The method for preparing an organic photoelectrochemical transistor sensing platform for detecting microcystin as described in claim 1, characterized in that the organic photoelectrochemical transistor is prepared by the following steps: The source and drain electrodes were integrated with an organic semiconductor layer to construct a conductive channel, and a photosensitive gate electrode was used as the control terminal. The specific fabrication steps are as follows: First, a glass substrate with a size of 15 mm × 18 mm was ultrasonically cleaned with acetone, ethanol and ultrapure water in sequence, followed by drying. After fixing the mask on the substrate, a 12 nm thick chromium layer and an 80 nm thick gold layer were sequentially prepared by magnetron sputtering to form the source and drain electrodes. The length and width of the conductive channel between the two electrodes were set to 0.4-0.5 mm and 8-10 mm, respectively. After the prepared template was treated with a plasma cleaning device for 4-5 minutes, a PEDOT:PSS solution was coated on the surface of the conductive channel using a spin coating device to form a polymer coating. To improve the bonding strength of the coating on the FTO substrate, the device was placed in a nitrogen environment and annealed at 150 °C for 1 hour.

[0010] Beneficial results of the present invention (1) The organic photoelectrochemical transistor sensing platform of the present invention uses CuIn2S4 as a photoactive material, which provides excellent photocurrent response and a large number of active sites, promoting the attachment of capture antibodies. (2) By optimizing the preparation process of CuIn2S4 material, the separation efficiency of photogenerated electron-hole pairs was improved, and the problem of short carrier lifetime caused by carrier recombination was solved. (3) The polydopamine nanospheres introduced into the sensing platform realize the signal amplification effect, and by utilizing their own specific binding ability, they work synergistically with CuIn2S4 material to further enhance the detection sensitivity. (4) The sensing platform based on organic photoelectrochemical transistors has good selectivity and stability for microcystin toxins and high sensitivity detection performance for target substances, which meets the needs of practical applications. Detailed Implementation Plan

[0011] Example 1 1. (1) Preparation of polydopamine nanosphere composite material linked to the second antibody Weigh 50 mg of dopamine hydrochloride and 0.1 g of copper chloride, dissolve them in 90 mL of deionized water, and then sonicate for 10 minutes. Transfer the resulting solution to a constant temperature stirrer and stir continuously at 70 °C for 4 hours. After the reaction is complete, wash the product with methanol and deionized water by centrifugation until neutral, and dry the product at 40 °C overnight. The dried nanomaterials were dispersed in 5 mL of pH 7.25 phosphate buffer (20 μg / mL microcystin secondary antibody was added, and the mixture was shaken at room temperature for 0.5 hours, then 3% bovine serum albumin solution was slowly added to block the non-specific binding sites on the surface of the material, and the mixture was shaken vigorously for 1 hour before centrifugation and washing. Finally, the product was dispersed in 5 mL of pH 7.25 phosphate buffer and stored at 4°C for later use). (2) Fabrication of organic photoelectrochemical transistor sensing platform 1) Cut and pretreat indium tin oxide conductive glass to obtain the required ITO electrodes; 2) 100 μL of CuIn2S4 photoelectric material with a concentration of 8-10 mg / mL was dropped onto the ITO electrode, and then calcined in a muffle furnace at 150 °C for 2 hours to ensure a tighter bond between the photoelectric material and the electrode; 3) Add 5 μL of 0.6 mol / L mercaptoacetic acid to the CuIn2S electrode and incubate for 3 hours. Then, add 6 μL of 20 μg / mL microcystin primary antibody, 2% bovine serum albumin and different concentrations of microcystin to the electrode and let them stand at 37 °C for 30 minutes to fix them onto the modified electrode. 4) 10 μL of the prepared second antibody-linked polydopamine nanospheres were left to stand at 4 °C for 1 h and were specifically bound to microcystin and fixed on the photoelectric material-modified electrode. 5) Place the photoelectric modified electrode and organic transistor under the workstation for signal testing; 2. The polydopamine nanospheres are prepared by the following steps: Weigh 60 mg of dopamine hydrochloride and 0.2 g of copper chloride, dissolve them in 80 mL of deionized water, and then sonicate for 5-10 minutes. Transfer the resulting solution to a constant temperature stirrer and stir continuously at 80 °C for 4 hours. After the reaction is complete, wash the product with methanol and deionized water by centrifugation until neutral, and dry the product at 40 °C overnight. The dried nanomaterials were dispersed in 5 mL of pH 7.25 phosphate buffer, 10 μg / mL microcystin secondary antibody was added, and the mixture was shaken at room temperature for 0.5 hours. Then, 2% bovine serum albumin solution was slowly added to block the non-specific binding sites on the surface of the material. After vigorous shaking for 1 hour, the mixture was centrifuged and washed. Finally, the product was dispersed in 5 mL of pH 7.25 phosphate buffer and stored at 4°C for later use. 3. The preparation steps of the aforementioned photoelectric material CuIn2S4 are as follows: Preparation of CuIn2S4 material: First, 0.7 g of copper nitrate and 0.4 g of indium nitrate were dissolved in 20 mL of deionized water and stirred for 10 minutes under magnetic stirring. Then, the copper nitrate and indium nitrate solutions were mixed and stirred thoroughly. The mixed solution was transferred to a reaction vessel and subjected to hydrothermal reaction at 150 °C for 20 hours. After the reaction was completed, the mixture was cooled to room temperature, the precipitate was collected by centrifugation, and washed several times with deionized water. The washed precipitate was dried at 80 °C for 12 hours, then calcined at 230 °C for 30 minutes. Finally, after cooling to room temperature, the solid powder was ground to obtain CuIn2S4 nanoparticles. 4. The organic photoelectrochemical transistor is prepared by the following steps: The source, drain, and organic semiconductor layers were integrated to construct a conductive channel, with a photosensitive gate electrode as the control terminal. The specific fabrication steps are as follows: First, a 15 mm × 18 mm glass substrate was ultrasonically cleaned sequentially with acetone, ethanol, and ultrapure water, followed by drying. After fixing a mask on the substrate, a 12 nm thick chromium layer and an 80 nm thick gold layer were sequentially fabricated using a magnetron sputtering device to form the source and drain. The length and width of the conductive channel between the two electrodes were set to 0.5 mm and 8-10 mm, respectively. After the prepared template was treated with a plasma cleaning device for 4 minutes, a PEDOT:PSS solution was coated on the surface of the conductive channel using a spin coating device to form a polymer coating. To improve the bonding strength of the coating on the FTO substrate, the device was placed in a nitrogen environment and annealed at 150 °C for 1 hour.

Claims

1. A method for preparing an organic photoelectrochemical transistor sensing platform for detecting microcystin, characterized in that, Includes the following steps: (1) Preparation of polydopamine nanosphere composite material linked to the second antibody Weigh 50-60 mg of dopamine hydrochloride and 0.1-0.2 g of copper chloride and dissolve them in 80-90 mL of deionized water. Then, sonicate the solution for 5-10 minutes. Transfer the resulting solution to a constant temperature stirrer and stir continuously at 70-80℃ for 4-5 hours. After the reaction is complete, wash the solution with methanol and deionized water by centrifugation until neutral. Dry the product at 40-50℃ overnight. The dried nanomaterials were dispersed in 5 mL of pH 7.25 phosphate buffer (PB), 10-20 μg / mL microcystin secondary antibody was added, and the mixture was shaken at room temperature for 0.5 hours. Then, 2-3% bovine serum albumin solution was slowly added to block the non-specific binding sites on the surface of the material. After vigorous shaking for 1 hour, the mixture was centrifuged and washed. Finally, the product was dispersed in 5 mL of pH 7.25 phosphate buffer and stored at 4°C for later use. (2) Fabrication of organic photoelectrochemical transistor sensing platform 1) Cut and pretreat indium tin oxide conductive glass to obtain the required ITO electrodes; 2) Drop 100-120 μL of CuIn2S4 photoelectric material with a concentration of 8-10 mg / mL onto the ITO electrode, and then calcine it in a muffle furnace at 150-200 ℃ for 2-3 hours to ensure a tighter bond between the photoelectric material and the electrode; 3) Add 5-6 μL of 0.5-0.6 mol / L mercaptoacetic acid to the CuIn2S electrode and incubate for 2-3 hours. Then, add 4-6 μL of 15-20 μg / mL microcystin primary antibody, 2% bovine serum albumin, and different concentrations of microcystin to the electrode and let them stand at 37 °C for 30 minutes to fix them onto the modified electrode. 4) 10-15 μL of the prepared second antibody-linked polydopamine nanospheres were left to stand at 4 °C for 1 h and then immobilized on the photoelectric material-modified electrode by specifically binding to microcystin. 5) Place the photoelectric modified electrode and organic transistor under the workstation for signal testing.

2. The method for preparing an organic photoelectrochemical transistor sensing platform for detecting microcystin as described in claim 1, characterized in that, The polydopamine nanospheres are prepared using the following steps: Weigh 50-60 mg of dopamine hydrochloride and 0.1-0.2 g of copper chloride, dissolve them in 80-90 mL of deionized water, and then sonicate for 5-10 minutes. Transfer the resulting solution to a constant temperature stirrer and stir continuously at 70-80℃ for 4-5 hours. After the reaction is complete, wash the product with methanol and deionized water by centrifugation until neutral, and dry the product at 40-50℃ overnight. The dried nanomaterials were dispersed in 5 mL of pH 7.25 phosphate buffer, and 10-20 μg / mL of microcystin secondary antibody was added. After shaking at room temperature for 0.5 hours, 2-3% bovine serum albumin solution was slowly added to block the non-specific binding sites on the surface of the material. After vigorous shaking for 1 hour, the material was centrifuged and washed. Finally, the product was dispersed in 5 mL of pH 7.25 phosphate buffer and stored at 4°C for later use.

3. The method for preparing an organic photoelectrochemical transistor sensing platform for detecting microcystin as described in claim 1, characterized in that, The preparation steps for the aforementioned photoelectric material CuIn2S4 are as follows: Preparation of CuIn2S4 material: First, 0.7-0.9 g of copper nitrate and 0.4-0.5 g of indium nitrate were dissolved in 20-25 mL of deionized water and stirred under magnetic stirring for 10-15 minutes. Then, the copper nitrate and indium nitrate solutions were mixed and stirred thoroughly. The mixed solution was transferred to a reaction vessel and subjected to hydrothermal reaction at 140-150℃ for 18-20 hours. After the reaction was completed, the mixture was cooled to room temperature, the precipitate was collected by centrifugation, and washed several times with deionized water. The washed precipitate was dried at 70-80℃ for 12 hours, and then calcined at 200-230℃ for 20-30 minutes. Finally, after cooling to room temperature, the solid powder was ground to obtain CuIn2S4 nanoparticles.

4. The method for preparing an organic photoelectrochemical transistor sensing platform for detecting microcystin as described in claim 1, characterized in that, The organic photochemical transistor is fabricated using the following steps: The source, drain, and organic semiconductor layers are integrated to construct a conductive channel, with a photosensitive gate electrode as the control end. The specific fabrication steps are as follows: First, a 15 mm × 18 mm glass substrate is ultrasonically cleaned sequentially with acetone, ethanol, and ultrapure water, followed by drying. After fixing a mask on the substrate, a 12 nm thick chromium layer and an 80 nm thick gold layer are sequentially fabricated using a magnetron sputtering device to form the source and drain. The length and width of the conductive channel between the two electrodes are set to 0.4-0.5 mm and 8-10 mm, respectively. After the prepared template is treated with a plasma cleaning device for 4-5 minutes, a PEDOT:PSS solution is coated on the surface of the conductive channel using a spin coater to form a polymer coating. To improve the bonding strength of the coating on the FTO substrate, the device is placed in a nitrogen environment and annealed at 150 °C for 1 hour.