Photo-assisted water-volatilization self-powered sensor and preparation method and application thereof

Abstract

The application belongs to the field of electrochemical detection, and particularly relates to a light-assisted water-vapor self-powered sensor and a preparation method and application thereof. A glass substrate is used as a substrate, a copper foil tape is used as a positive and negative electrode, a BiOBr-PANI composite material is used as a power generation material to prepare a water-vapor generator, and an MC-RR aptamer is assembled to construct a water-vapor self-powered sensor. The power generation material is a BiOBr-PANI composite material, light assistance is combined into the water-vapor self-powered sensor, and the water-vapor self-powered sensor significantly improves the generated electric output under light assistance. The application widens the application of BiOBr and PANI in water-vapor induced power generation, provides a new strategy for electrochemical detection, and the constructed light-assisted water-vapor self-powered sensor has a wide detection range, high sensitivity, low detection limit and detection cost.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of electrochemical detection, and particularly relates to a light-assisted water-driven self-powered sensor and a preparation method and application thereof, and more particularly relates to a BiOBr-PANI composite material as a base material, an aptamer (apta) with specific recognition as a recognition unit, which are collectively modified on a functional glass material coating surface, to form an apta / BiOBr-PANI / glass light-assisted water-driven self-powered sensor, and an electrochemical analysis method for quantitatively detecting microcystin MC-RR in wastewater. BACKGROUND

[0002] Microcystins (MCs) are a kind of cyclic heptapeptide toxins, which are produced by secondary metabolites of Microcystis cyanobacteria, and have hepatotoxicity, neurotoxicity, immunotoxicity and reproductive toxicity, and are also confirmed as a liver cancer promoter. There are more than 70 structural variants of MCs, and several of them with relatively high content and toxicity include MC-LR, MC-RR and MC-YR. Among them, MC-RR is highly toxic and has a high content, and the harm caused by it may be greater than that of other variants.

[0003] At present, various technologies have been used to detect MCs. For example, patent CN108426971A uses high performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS) for detection, which has the advantages of high sensitivity, good stability, high accuracy, etc., but also has the disadvantages of expensive and complex instruments, time-consuming sample analysis, low throughput, etc., and usually requires professional personnel to operate these advanced equipment. Another method for detecting MCs is immunoassay, including enzyme-linked immunosorbent assay (ELISA), lateral flow immunoassay (LFIA) and enzyme-linked immunosensor, such as patents CN111912986A and CN111718412A, etc. This method has high sensitivity, but its quality usually depends on the quality of the antibody used.

[0004] Compared with traditional energy conversion devices, water-driven power generation devices can be applied in various situations without additional input of mechanical energy. Through the direct interaction between materials and water, the heat in the environment can be directly converted into electrical energy output, which is a clean and pollution-free green new energy conversion technology. Light assistance can increase the current response, making the sensor reaction more sensitive. For example, patent CN114527176A constructs a photoelectrochemical self-powered sensor for microcystin detection with TiO2 / Ti3C2 / ITO as the anode and CTS / MoS2 / Ti3C2 / ITO as the cathode, but the preparation method of the sensor is complex. At present, there are still relatively few studies on the establishment of a self-powered sensing platform based on light-assisted water-driven power generation devices for electrochemical detection of microcystins. SUMMARY

[0005] The application aims to provide a light-assisted water-voltaic self-powered sensor and a preparation method and application thereof.

[0006] One of the purposes of the application is to provide a light-assisted water-voltaic self-powered sensor, which comprises a BiOBr-PANI composite material as a power generation material and an aptamer (apta) with specific recognition as a recognition unit, and is collectively modified on a functional glass material coating surface to form an apta / BiOBr-PANI / glass substrate light-assisted water-voltaic self-powered sensor.

[0007] The second purpose of the application is to provide a preparation method of the above-mentioned light-assisted water-voltaic self-powered sensor, and the specific steps are as follows:

[0008] (1) Preparation of bismuth oxybromide;

[0009] Bi(NO3)3.5H2O, mannitol and polyvinylpyrrolidone (PVP) are added to deionized water and stirred vigorously. Then, KBr is added to the above mixture. After stirring for 1 hour, the mixture is transferred to a 50mL polytetrafluoroethylene lined autoclave and sealed, and then subjected to hydrothermal reaction. The product is collected by centrifugation, washed with deionized water several times, and dried in a vacuum oven.

[0010] (2) Preparation of bismuth oxybromide-polyaniline (BiOBr-PANI) composite material:

[0011] BiOBr and 98% polyaniline (emeraldine base) are added to a 5ml centrifuge tube, and a suspension prepared by mixing anhydrous ethanol and deionized water in a volume ratio of 1:1 is added thereto, and ultrasonic dispersion is performed to obtain a uniform BiOBr-PANI composite material suspension.

[0012] (3) Construction of water-voltaic cell:

[0013] The glass substrate is sequentially cleaned in acetone, ethanol and ultrapure water for 30min. The glass is used as the substrate, and the copper foil tape is used as the electrode to stick the upper electrode in the shape of "one" and the lower electrode in the shape of "L". The BiOBr-PANI composite material suspension is added between the upper and lower electrodes by using a pipette gun to make it evenly spread between the two electrodes. Finally, the prepared device is dried in a 60℃ vacuum drying oven.

[0014] (4) Preparation of sensor

[0015] A certain concentration of MC-RR aptamer is added to the surface of the water-voltaic cell power generation material prepared in step (3). Natural drying at room temperature obtains an aptamer sensor with selective recognition for MC-RR.

[0016] Further, in the step (1), the mass ratio of Bi(NO3)3·5H2O, mannitol, PVP, and KBr is 480-490: 590-610: 190-210: 170-180.

[0017] Further, in the step (1), the hydrothermal reaction temperature is 140-180℃, and the reaction time is 2-4h.

[0018] Further, in the step (2), the concentration of the BiOBr-PANI composite material suspension is 20mg / ml, and the ultrasonic dispersion time is 4-8h.

[0019] Further, in the step (2), the mass ratio of BiOBr and polyaniline (turquoise imine group) is 1:1-3; preferably, the mass ratio of BiOBr and polyaniline (turquoise imine group) is 1:1-2.

[0020] Further, in the step (3), the drop coating amount is 50-85μL / cm 2 In some specific embodiments of the present application, the drop coating area is 2.0*3.0cm 2 , and the coating amount is 300-500μL.

[0021] Further, in the step (4), the concentration of the MC-RR aptamer is 1M, the dropwise addition amount is 3μL / cm 2 , and the incubation time of the aptamer is 6h.

[0022] The application of the self-powered sensor in the photoelectrochemical detection of MC-RR, the nucleotide sequence of the MC-RR aptamer is the same as that in CN114527176A, and the specific sequence is as follows:

[0023] Aptamer: 5'-CAG CTC AGAAGC TTG ATC CTA CTG CCC TTC AAT GTT CAC TCC TGTTTC CTGATC TTT GTC GAC TCGAAG TCG TGC ATC TG-3'.

[0024] The third object of the present application is to provide the application of the above-mentioned photo-assisted water-voltaic self-powered sensor in the detection of microcystin (MC-RR).

[0025] The specific detection method comprises the following steps:

[0026] S1, preparing microcystin MC-RR with different concentrations;

[0027] Accurately take a certain amount of MC-RR, dilute with deionized water step by step, and obtain a series of microcystin standard solutions with different concentrations, and the concentration range is 1.0*10 -15 mol / L~1.0*10 -9 mol / L;

[0028] S2, drawing of standard curve:

[0029] A series of MC-RR standard solutions with known concentrations are selected and dropped on the surface of the prepared water-voltaic cell power generation material, and naturally dried at room temperature;

[0030] The copper foil tape upper and lower electrodes are used as the positive and negative electrodes of the electrochemical test, the BiOBr-PANI composite material is used as the power generation material, and the MC-RR aptamer is assembled to form a water-voltaic self-powered system, deionized water is used as the electrolyte, the current of the xenon lamp light source is controlled to be 20A, the horizontal distance from the light source outlet to the glass substrate is 10cm, the short-circuit current response value is measured at a test potential of 0V, a series of concentration-short-circuit current corresponding relationships are obtained, and then the standard curve of MC-RR is obtained, the linear relationship between the short-circuit current intensity after adding MC-RR and the logarithmic value of the concentration of MC-RR is established, and the corresponding linear regression equation is obtained.

[0031] S3, actual sample detection:

[0032] The actual sample is pretreated before detection, and then the pH value is adjusted, and the linear regression equation in step S2 is calculated.

[0033] As preferred: in step S3, the light-assisted water-voltaic self-powered sensor reaction time is 20min.

[0034] The minimum detection limit of the MC-RR solution concentration detected by the sensor is 3.10*10 -15 M.

[0035] The present application has the following three advantages compared with the traditional sensor:

[0036] (1) The present application uses BiOBr / PANI composite material as power generation material to prepare water-voltaic device. The ordinary glass is used as the base material, the BiOBr is in a layered structure, the band gap is small, and it can respond to visible light, and the PANI is used to enhance ion transmission and photoelectric response. In the preparation of the light-assisted water-voltaic self-powered sensor, the light assistance significantly improves the current signal, and the addition of the aptamer makes the sensor can specifically detect MC-RR.

[0037] (2) Compared with traditional detection methods, the water-volt electrochemical detection method proposed in this invention has the characteristics of simple and flexible operation, simple instruments and equipment, high sensitivity, wide linear range, low detection limit and low detection cost. Attached Figure Description

[0038] The present invention will be further described below with reference to the accompanying drawings and examples.

[0039] Figure 1 This is a schematic diagram illustrating the fabrication of the sensor and the detection of MC-RR in this invention.

[0040] Figure 2 This is the short-circuit current diagram of the self-powered sensor of the MC-RR in the standard solution of Example 1.

[0041] Figure 3 This is a standard curve of the short-circuit current after adding MC-RR in Example 1 versus the logarithm of MC-RR concentration.

[0042] Figure 4 These are the current signals of the water-volt batteries made of composite materials with different proportions in Example 2.

[0043] Figure 5 This is a scanning electron microscope image of the BiOBr-PANI composite material prepared in Example 1 of this invention. Detailed Implementation

[0044] The present invention will be further described in detail below with reference to the embodiments.

[0045] like Figure 1 As shown, a method for preparing a photovoltaic self-powered sensor and its application in MC-RR detection is described. A photovoltaic generator is prepared using BiOBr-PANI composite material as the power generation material to form a self-powered system, and an MC-RR aptamer is assembled to achieve specific detection of MC-RR.

[0046] Example 1: A method for constructing a photovoltaic self-powered sensor and its application in detecting microcystin, comprising the following steps:

[0047] (1) Preparation of bismuth oxybromide;

[0048] 486 mg of Bi(NO3)3·5H2O, 600 mg of mannitol, and 200 mg of polyvinylpyrrolidone (PVP) were added to 30 mL of deionized water and stirred vigorously for 10 minutes. Then, 178.5 mg of KBr was added to the mixture. After stirring for 1 hour, the mixture was transferred to a 50 mL PTFE-lined autoclave and sealed, then heated at 160 °C for 3 hours. The product was collected by centrifugation, washed several times with deionized water, and dried in a vacuum oven at 60 °C for 10 hours.

[0049] (2) Preparation of BiOBr / PANI composite material:

[0050] 40 mg of BiOBr and 40 mg of 98% polyaniline (emeraldine base) were added to a 5 ml centrifuge tube, 2 ml of anhydrous ethanol and deionized water with a volume ratio of 1:1 were added to prepare a suspension, and ultrasonic dispersion was performed for 5 hours to obtain a uniform BiOBr / PANI composite suspension material.

[0051] (3) Construction of water-voltaic cell:

[0052] The glass substrate was sequentially cleaned in acetone, ethanol and ultrapure water for 30 min. The glass was used as the substrate, and the copper foil tape was used as the electrode to paste the upper electrode in the shape of "1" and the lower electrode in the shape of "L". The BiOBr / PANI composite suspension material was added between the upper and lower electrodes by using a pipette, so that it was evenly spread between the two electrodes. The drop-coating area was 2.0*3.0 cm 2 , and the coating amount was 400 μL. Finally, the prepared device was dried in a 60°C vacuum drying oven.

[0053] (4) Preparation of sensor

[0054] The water-voltaic cell power generation material prepared in step (3) was added with a certain concentration of MC-RR aptamer. After natural drying at room temperature, an aptamer sensor with selective recognition for MC-RR was obtained.

[0055] The aptamer sequence of the above sensor is as follows: aptamer: 5'-CAG CTC AGA AGC TTG ATC CTA CTG CCC TTC AAT GTT CAC TCC TGT TTC CTG ATC TTT GTC GAC TCG AAG TCG TGC ATC TG-3'.

[0056] (5) Drawing of standard curve:

[0057] A standard solution of MC-RR was prepared by dissolving MC-RR in 10 ml of deionized water, and then diluting with deionized water step by step to obtain a series of MC-RR standard solutions with different concentrations;

[0058] In the light-assisted water self-powered sensor, the copper foil tape upper and lower electrodes were used as the positive and negative electrodes of the electrochemical test, the BiOBr / PANI composite material was used as the power generation material, and the MC-RR aptamer was assembled to form a water self-powered system. The self-powered aptamer sensor incubation time was 20 min, deionized water was used as the electrolyte, the xenon lamp light source current was controlled to be 20 A, the horizontal distance from the light source outlet to the glass substrate was 10 cm, and the short-circuit current response value was measured at a test potential of 0 V, as shown in Figure 2 Fig. 1, wherein the concentrations of MC-RR from top to bottom (a→g) according to the peak height of the curve are as follows:

[0059] 1.0×10 -15 mol / L, 1.0×10 -14 mol / L, 1.0×10 -13 mol / L, 1.0×10 -12 mol / L, 1.0×10 - 11 mol / L, 1.0×10 -10 mol / L, 1.0×10 -9 mol / L.

[0060] The electrodes modified with different concentrations of MC-RR were used as working electrodes, wherein the concentrations of MC-RR were 1.0×10 -15 mol / L, 1.0×10 -14 mol / L, 1.0×10 -13 mol / L, 1.0×10 -12 mol / L, 1.0×10 -11 mol / L, 1.0×10 -10 mol / L, 1.0×10 -9 mol / L, deionized water was used as the electrolyte, the xenon lamp light source current was selected to be 20 A, the horizontal distance from the light source outlet to the glass substrate was 10 cm, and the response value of the electric power was measured at a test potential of 0 V; then the linear relationship between the logarithmic value of the concentration of MC-RR and the short-circuit current was obtained, as shown in Figure 3 Fig. 2, the correlation coefficient (R) was 0.97107, the detection range of the linear regression equation was 1.0×10 -15 -1.0×10 -9 mol / L, and the lowest detection limit was 3.10×10 -15 mol / L.

[0061] (6) Sample detection

[0062] A certain amount of impurity-removed wastewater was configured into MC-RR solution, which was used for photoelectrochemical detection, and the concentration of MC-RR in the sample to be detected was calculated according to the regression equation corresponding to step (5) above, and the results are shown in Table 1.

[0063] Table 1 Determination results of MC-RR in water samples

[0064]

[0065] As shown in Table 1, the sample was detected in parallel for 3 times, the relative standard deviation was less than 5%, and the recovery rate of the standard addition was 94% to 101%. The application can be realized for detecting MC-RR in wastewater.

[0066] Example 2: Comparison of the effects of different mass ratios of BiOBr / PANI composite materials on the performance of the sensor.

[0067] The mass ratio of the BiOBr / PANI composite material was changed, and the preparation steps of the water-activated battery and the assembly of the sensor were the same as in Example 1.

[0068] The water-activated battery was prepared using different ratios of BiOBr / PANI composite materials, which were (3:1, 2:1, 1:1, 1:2, 1:3), and the specific amounts of BiOBr and PANI in 2ml of solvent were 30mg:10mg, 26.66mg:13.34mg, 20mg:20mg, 13.34mg:26.66mg, and 10mg:30mg, respectively. Deionized water was used as the electrolyte, the current of the xenon lamp source was selected to be 20A, the horizontal distance from the light source outlet to the glass substrate was 10cm, and the short-circuit current response value was measured at a test potential of 0V.

[0069] From the above, Figure 4 It can be seen that the short-circuit current continuously increases with the increase of the proportion of PANI. When the mass ratio of BiOBr / PANI is 1:1, the short-circuit current is the largest. Therefore, the optimal ratio of the BiOBr / PANI composite material is 1:1.

[0070] The above-described ideal embodiments according to the application are for inspiration, and through the above-described description, relevant personnel can make various changes and modifications without deviating from the scope of the technical idea of the application. The technical scope of the application is not limited to the content in the specification, and the technical scope must be determined according to the scope of the claims.

Claims

1. A photo-assisted hydrovoltaic self-powered sensor for MC-RR detection, characterized in that, The photo-assisted water-voltaic self-powered sensor includes a BiOBr-PANI composite material as the power generation material and an aptamer with specific recognition as the recognition unit, which are jointly modified on the surface of the functional glass to form an apta / BiOBr-PANI / glass substrate photo-assisted water-voltaic self-powered sensor; The preparation method of the photo-assisted water-voltaic self-powered sensor includes the following preparation steps: Step (1): Disperse BiOBr and polyaniline (verdigris imino group) in a mixed solution of anhydrous ethanol and deionized water with a volume ratio of 1:1 and ultrasonically disperse them evenly to obtain a BiOBr-PANI composite material suspension; the concentration of the BiOBr-PANI composite material in the suspension is 20 mg / ml; Step (2): Use the pre-cleaned functional glass as the substrate and copper foil tape as the electrode, paste the upper electrode in the shape of "one" and the lower electrode in the shape of "L", and drop the BiOBr-PANI composite material suspension between the upper and lower electrodes to evenly cover the space between the two electrodes, and dry to obtain a photo-assisted water-voltaic battery; Step (3): Drop the MC-RR aptamer on the surface of the power generation material of the water-voltaic battery prepared in Step (2) and dry it naturally at room temperature to obtain a photo-assisted water-voltaic self-powered sensor for MC-RR detection; the sequence of the MC-RR aptamer is: 5’-CAG CTC AGAAGC TTG ATC CTA CTG CCC TTC AAT GTT CAC TCC TGT TTC CTG ATC TTT GTC GAC TCGAAG TCG TGC ATC TG-3’.

2. A method for fabricating a photovoltaic self-powered sensor for MC-RR detection as described in claim 1, characterized in that, It includes the following preparation steps: Step (1): Disperse BiOBr and polyaniline (verdigris imino group) in a mixed solution of anhydrous ethanol and deionized water with a volume ratio of 1:1 and ultrasonically disperse them evenly to obtain a BiOBr-PANI composite material suspension; the concentration of the BiOBr-PANI composite material in the suspension is 20 mg / ml; Step (2): Use the pre-cleaned functional glass as the substrate and copper foil tape as the electrode, paste the upper electrode in the shape of "one" and the lower electrode in the shape of "L", and drop the BiOBr-PANI composite material suspension between the upper and lower electrodes to evenly cover the space between the two electrodes, and dry to obtain a photo-assisted water-voltaic battery; Step (3): Drop the MC-RR aptamer on the surface of the power generation material of the water-voltaic battery prepared in Step (2) and dry it naturally at room temperature to obtain a photo-assisted water-voltaic self-powered sensor for MC-RR detection; the sequence of the MC-RR aptamer is: 5’-CAG CTC AGAAGC TTG ATC CTA CTG CCC TTC AAT GTT CAC TCC TGT TTC CTG ATC TTT GTC GAC TCGAAG TCG TGC ATC TG-3’.

3. The method for preparing a photovoltaic self-powered sensor for MC-RR detection according to claim 2, characterized in that, In Step (1), the mass ratio of BiOBr to polyaniline (verdigris imino group) is 1:1~3.

4. The method for preparing a photovoltaic self-powered sensor for MC-RR detection according to claim 2, characterized in that, In Step (1), the ultrasonic dispersion time is 4-8 hours.

5. The method for preparing a photovoltaic self-powered sensor for MC-RR detection according to claim 2, characterized in that, In step (2), the droplet application rate of the BiOBr-PANI composite material suspension is 50~85 μL / cm. 2 .

6. The method for preparing a photovoltaic self-powered sensor for MC-RR detection according to claim 2, characterized in that, In step (3), the concentration of MC-RR aptamer is 1 mol / L, and the dropping volume is 3 μL / cm. 2 The aptamer incubation time is 6 hours.

7. The method for preparing a photovoltaic self-powered sensor for MC-RR detection according to claim 2, characterized in that, In step (1), BiOBr is prepared by the following method: Bi(NO3)3·5H2O, mannitol and polyvinylpyrrolidone (PVP) are added to deionized water and stirred vigorously; then KBr is added; after stirring for 1 hour, the mixture is transferred to an autoclave and sealed, and hydrothermally reacted at 140-180℃ for 2-4 hours. The product is collected by centrifugation, washed several times with deionized water, and dried in a vacuum oven. The mass ratio of Bi(NO3)3·5H2O, mannitol, PVP, and KBr is 480~490:590~610:190~210:170~180.

8. An application of the photovoltaic self-powered sensor for MC-RR detection as described in claim 1, characterized in that, Using deionized water as the electrolyte, the xenon lamp light source current was controlled at 20 A, and the horizontal distance from the light source outlet to the glass substrate was 10 cm. The short-circuit current intensity of the photo-assisted water-volt self-powered sensor described in claim 1 before and after bonding with the sample was measured at a test potential of 0 V. The concentration of MC-RR in the sample was calculated according to the linear regression equation of the standard curve.

9. The application of the photovoltaic self-powered sensor for MC-RR detection according to claim 8, characterized in that, The binding time between the sample and the aptamer is 10-60 min.

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