Preparation method and application of MoS2-Ti / Au modified PET film electrode molecularly imprinted electrochemical sensor

Abstract

The invention provides a preparation method and application of a MoS2-Ti / Au modified PET (Polyethylene Terephthalate) film electrode molecularly imprinted electrochemical sensor. Comprising the following steps: step 1, preparing a MoS2-Ti / Au electrode material; step 2, preparing a Prussian blue solution; step 3, preparing a pyrrole solution; 4, preparing a molecular polymerization solution; 5, carrying out an electropolymerization reaction; and step 6, carrying out elution on the polymerized MIP electrode. The invention provides a preparation method and application of a MoS2-Ti / Au modified PET (Polyethylene Terephthalate) film electrode molecularly imprinted electrochemical sensor, the MoS2-Ti / Au modified electrode is used for preparing the molecularly imprinted electrochemical sensor and detecting serotonin, the MoS2-Ti / Au modified electrode has good reproducibility, acceptable stability and high selectivity, and the MoS2-Ti / Au modified electrode is used for preparing the molecularly imprinted electrochemical sensor and detecting serotonin. The target object can be detected more quickly, accurately and effectively.

Description

Technical Field

[0001] The invention relates to the field of molecular imprinting electrochemical sensors, and in particular to a preparation method and application of a MoS2-Ti / Au modified PET thin film electrode molecular imprinting electrochemical sensor. Background Art

[0002] As a typical transition metal disulfide material, MoS2 is one of the most widely studied and applied graphene-like nanomaterials. MoS2 has excellent mechanical properties, excellent biocompatibility, outstanding electrochemical catalytic performance, and high specific surface area, which has enabled the rapid development of MoS2-based sensors. In the field of electrochemical sensing, MoS2 can be used as an electron transfer medium or electrocatalyst to amplify the signal. Electrochemical sensing is an analytical method that analyzes the components of the substance to be measured by monitoring the changes in the electrochemical signal of the sensor element. Traditional electrochemical sensors usually use glassy carbon electrodes or ITO glass electrodes. Although these electrodes have excellent performance, their preparation and pretreatment are complex and costly. In contrast, ultra-thin plastic substrates such as polyethylene terephthalate (PET) have become ideal flexible platforms for preparing electrodes due to their low cost, excellent thermal strength, good ink compatibility, and mechanical elasticity after multiple bending and torsion.

[0003] Molecular imprinting technology (MIT), also known as template imprinting technology, is a technology for artificially synthesizing polymers with high specific selectivity for specific target molecules (template molecules). The molecular imprinting polymers (MIPs) produced by this technology have functional group arrangements and specific pore sizes and shapes that are complementary to the template molecules, thereby showing high recognition capabilities for the template molecules. The high stability and specificity of MIPs enable them to be "tailor-made" for any molecule, with low production costs and easy large-scale production. Electrochemical biosensors based on molecular imprinting polymers combine many advantages of molecular imprinting polymers and electrochemical biosensors, such as high selectivity, high sensitivity, chemical / mechanical stability, reusability, low detection limit, simple preparation, and low cost, so they have attracted much attention in the preparation of electrochemical sensors. However, as a polymer membrane material, MIPs have poor conductivity, which limits their application in electrochemical sensing. The molecular imprinting electrochemical sensors reported so far face problems such as low sensitivity, few effective sites, nonspecific adsorption, and slow elution. In order to overcome these shortcomings and improve the conductivity of the sensor, the selection of conductive substrates with high specific surface area structures as components of sensor functional devices has received widespread attention. The preparation of MIPs on the surface of high specific surface area materials can produce a large number of recognition sites, thereby increasing the accumulation of analytes on the electrode surface. Therefore, it is of great significance to develop fast, accurate and sensitive detection equipment and methods. Summary of the invention

[0004] The purpose of the present invention is to provide a preparation method and application of a MoS2-Ti / Au modified PET thin film electrode molecular imprinting electrochemical sensor.

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

[0006] The present invention relates to a method for preparing a MoS2-Ti / Au modified PET thin film electrode molecular imprinting electrochemical sensor, which is characterized by comprising the following steps:

[0007] Step 1, preparation of MoS2-Ti / Au electrode material: slice the PET film, clean and dry it, sputter Ti and Au metals, and coat the MoS2 film on the electrode surface;

[0008] Step 2, preparing a Prussian blue solution: mixing FeCl3, K3[Fe(CN)6], KCl, and PBS solution, and stirring;

[0009] Step 3, prepare pyrrole solution: dissolve 100 μM monopyrrole solution (concentration ≥ 98%) in 5 mL of ethanol and stir until fully dissolved;

[0010] Step 4, preparing a molecular polymerization solution: dissolving the template molecule in 5 mL of water, adding a PBS solution, and then adding a Prussian blue solution and a pyrrole solution, stirring, standing, and taking the supernatant to prepare a molecular polymerization solution MIP solution;

[0011] Step 5, electropolymerization reaction: immersing the MoS2-Ti / Au electrode material in a molecular polymerization solution, depositing it on the surface of the electrode substrate using cyclic voltammetry to form a molecular imprinting film, polymerizing, and obtaining a polymerized MIP electrode;

[0012] S6, eluting the polymerized MIP electrode to wash away the template molecules on the molecular imprinting membrane, and obtaining a MoS2-Ti / Au modified PET thin film electrode molecular imprinting electrochemical sensor.

[0013] Preferably, in step 1, the specific steps of preparing the MoS2-Ti / Au electrode material are:

[0014] (1) Slice the PET film, clean it ultrasonically in an ethanol solution, soak it in deionized water, and blow dry it with N2;

[0015] (2) Using magnetron sputtering technology, Ti and Au metals are sputtered sequentially in a sputtering chamber;

[0016] (3) Use a micropipette to drop the MoS2 suspension onto the surface of the PET electrode containing Ti / Au, and let it stand at room temperature to fully dry to form a uniform film on the surface of the PET electrode.

[0017] Preferably, the thicknesses of the Ti and Au metals are 5 nm and 40 nm respectively.

[0018] Preferably, in step 2, the Prussian blue solution is prepared as follows: first, 10 mM FeCl3, 10 mM K3[Fe(CN)6], 10 mM KCl, and 5 mM PBS solution are mixed, and stirred at 400 rpm until uniformly prepared.

[0019] Preferably, in step 3, the stirring is carried out using a magnetic stirrer.

[0020] Preferably, in step 4, the concentration ratio of the Prussian blue solution, the pyrrole solution and the template molecule is 1:10:1; and the stirring is performed by a magnetic stirrer for 40 minutes.

[0021] Preferably, in step 5, the electropolymerization reaction is carried out in a three-electrode system, the working electrode is a MoS2-Ti / Au electrode, the counter electrode is a graphite electrode, and the reference electrode is a silver / silver chloride electrode; the deposited deposition liquid is a molecular imprinting polymerization solution; after the polymerization is completed, the electrodes are rinsed with water and left to be eluted.

[0022] Preferably, in step 6, the specific method of elution is: immersing the polymerized MIP electrode in an elution solvent PBS buffer solution, eluting with SWV at different frequencies in the potential range of -0.3 to 1.1 V, and the number of elutions is 8 to 15 times.

[0023] The present invention also relates to the application of the aforementioned MoS2-Ti / Au modified PET thin film electrode molecular imprinting electrochemical sensor, wherein the MoS2-Ti / Au modified PET thin film electrode molecular imprinting electrochemical sensor prepared according to claim 1 is used for selective detection of serotonin.

[0024] Preferably, the process of detecting serotonin is: immersing the polymerized MIP electrode of claim 1 in a PBS buffer solution, adding serotonin of different concentrations in sequence, and detecting its electrochemical response by using the SWV method.

[0025] The present invention has the following advantages:

[0026] (1) The MoS2-Ti / Au modified PET thin film electrode prepared by the method involved in the present invention not only increases the active catalytic sites by co-modifying the electrode with MoS2 and Ti / Au, but also improves the conductivity through the synergistic effect of the two, thereby enhancing the sensitivity and stability of the sensor and improving the sensing performance.

[0027] (2) The present invention is based on MoS2-Ti / Au modified PET thin film electrodes, which are used to prepare molecular imprinting electrochemical sensors, which can detect different substances, such as serotonin, according to different template molecules; the sensor has high reproducibility, stability and selectivity; the sensor is fast, efficient and accurate, and is easy to commercialize, and the preparation process is simple and the detection operation is convenient.

[0028] (3) The present invention uses pyrrole (Py) as a functional monomer, and utilizes Py as a functional monomer. The cyclic voltammetry method is used to directly polymerize Py and template molecules in a polymerization mixture on the surface of a MoS2-Ti / Au modified PET thin film electrode to entrap the template molecules in the polymer main chain; after the template molecules are subsequently removed from the polypyrrole (PPy) matrix, the resulting MIP membrane can selectively recognize the target molecules upon rebinding; since PPy has good conductivity, the preparation process is simple and environmentally friendly, and polypyrrole has biocompatibility and high selective permeability, it is an ideal material for preparing sensor sensitive membranes; the preparation process of this method is simple and can be achieved by only performing cyclic voltammetry scanning in a solution of the functional monomer and the template molecule; the preparation device is simple, the conditions are easy to control, and the thickness of the polymer film can be accurately controlled to ensure that the film thickness is uniform and has high reproducibility; the polymer film has good rigidity, and after the template molecules are removed, the imprinted holes are not easily deformed, thereby ensuring repeatability; in addition, the sensor structure is stable, the imprinted layer is not easily detached during the elution process, and is easy to rebind with the template molecules, and can accurately and quickly determine the content of the analyte at low concentrations.

[0029] (4) The MoS2-Ti / Au modified PET thin film electrode molecular imprinting electrochemical sensor provided by the present invention is not only convenient, fast, efficient, but also low-cost. It overcomes the problems of insufficient specificity, low sensitivity, long detection cycle and complex operation of existing detection technologies. In addition, the sensor can be used for the determination of serotonin content in the human body. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The SEM comparison diagram of the MoS2-Ti / Au modified PET thin film electrode molecular imprinting electrochemical sensor involved in the present invention before and after elution; wherein a and b are low-magnification and high-magnification SEM diagrams of the sensor before elution, respectively; c and d are low-magnification and high-magnification SEM diagrams of the sensor after elution, respectively;

[0031] Figure 2 It is a detection curve diagram of the MoS2-Ti / Au modified PET thin film electrode molecular imprinting electrochemical sensor before and after elution and during the elution process involved in the present invention; wherein a is a curve diagram of the elution process of serotonin, and b is a test curve diagram before and after elution of serotonin;

[0032] Figure 3 The figure is a linear curve diagram of the detection of serotonin by the MoS2-Ti / Au modified PET thin film electrode molecular imprinting electrochemical sensor involved in the present invention; wherein a is a SWV response curve diagram of the sensor to serotonin at different concentrations of serotonin; b is a curve diagram of the relationship between serotonin concentration and peak current;

[0033] Figure 4 This is a graph showing the specific evaluation of the MoS2-Ti / Au modified PET thin film electrode molecular imprinting electrochemical sensor of the present invention for serotonin. DETAILED DESCRIPTION

[0034] The present invention is described in detail below in conjunction with specific embodiments. It should be noted that the following embodiments are only further descriptions of the present invention, but the protection scope of the present invention is not limited to the following embodiments.

[0035] Example

[0036] This embodiment relates to a method for preparing a MoS2-Ti / Au modified PET thin film electrode molecular imprinting electrochemical sensor, comprising the following steps:

[0037] Step 1, preparation of MoS2-Ti / Au electrode material: slice the PET film, clean it and blow dry it with N2, then use magnetron sputtering technology to plate Ti and Au on the PET film, the thickness of Ti and Au are 10nm and 40nm respectively, and finally generate MoS2 film on the electrode surface to obtain MoS2-Ti / Au electrode;

[0038] Step 2, prepare Prussian blue solution: weigh: 100 mg FeCl3, 100 mg K3[Fe(CN)6], 100 mg KCl in a beaker, add 50 mL PBS solution, stir for 40 min to mix evenly;

[0039] Step 3, prepare pyrrole solution: take 100 μL of monopyrrole solution with a concentration of ≥98% and dissolve it in 5 mL of ethanol;

[0040] Step 4, preparing molecular polymerization solution: weigh 43 mg of serotonin and dissolve it in 5 mL of water, pour it into a beaker containing 35 mL of PBS solution, and pour the Prussian blue solution and the pyrrole solution into the beaker respectively to prepare the molecular polymerization solution;

[0041] Step 5, electropolymerization reaction: immersing the MoS2-Ti / Au electrode material treated in step 1 into the molecular polymerization solution obtained in step 4, and performing electropolymerization treatment by cyclic voltammetry to form a molecular imprinting film on the surface of the PET film electrode to obtain a polymerized MIP electrode;

[0042] The specific steps are as follows: in a three-electrode system, a MoS2-Ti / Au electrode is used as a working electrode, a counter electrode is a graphite electrode, and a reference electrode is a silver / silver chloride electrode; a molecular imprinting film, i.e., a polymerized MIP electrode, is formed on the surface of the MoS2-Ti / Au electrode. In this embodiment, the number of scans is 20 and the scan rate is 25 mV / s;

[0043] Step 6, eluting the polymerized MIP electrode, washing off the template molecules on the molecular imprinting membrane, and obtaining a 5-HT molecular imprinting membrane modified PET thin film electrode, that is, the eluted MIP electrode; the specific steps are: immersing the polymerized MIP electrode in the elution solvent PBS solution, using a three-electrode system, using the polymerized MIP electrode as the working electrode, the counter electrode as a graphite electrode, and the reference electrode as a silver / silver chloride electrode. The SWV method is used for elution, and the parameters are set to: within the potential range of -0.3 to 1.1 V, the frequency is 15 Hz. After the elution is completed, the electrode surface is rinsed with pure water to obtain a MoS2-Ti / Au modified PET thin film electrode molecular imprinting electrochemical sensor.

[0044] 1. Test the products obtained during the preparation process

[0045] like Figure 1 As shown, Figure a and Figure b show the SEM images of the molecular imprinting electrochemical sensor before elution; Figure c and Figure d show the SEM images after elution. Figure 1 It can be seen that the sample morphology is spherical and relatively regular. By comparison, it is found that before elution, the sample surface contains many tiny particles, but after elution, these particles are removed, the surface roughness is reduced, and more vacancies are exposed. This is because the template molecules leave holes and imprinting sites on the electrode after being eluted, providing conditions for subsequent selective adsorption.

[0046] The MoS2-Ti / Au modified PET film electrode was used as the working electrode of the molecular imprinting electrochemical sensor, with a graphite electrode as the counter electrode and silver / silver chloride as the reference electrode. The SWV method was used for detection in the voltage range of 0-0.6V and the frequency of 60Hz. The elution process also used the SWV method. After elution, the electrode surface was rinsed with pure water to complete the preparation of the sensor.

[0047] Figure 2 The changes in the elution process of the molecularly imprinted electrochemical sensor made of MoS2-Ti / Au modified PET thin film electrode and the curves before and after elution. Figure 2Figure a shows the curve changes during the elution process. As the number of elutions increases, obvious peaks begin to appear. The initial peak current decreases because some substances on the polymer film, including the 5-HT template molecules, are eluted; after reaching a certain number of times, the curve begins to rise, indicating that more template molecules are eluted, and the imprinted film at the hole site covers the electrode surface, promoting electron transfer, and the peak current increases accordingly. When the peak value stabilizes, it indicates that the elution is complete. Figure 2 Figure b shows the test curves before and after elution. No obvious peak was observed before elution, but an obvious peak appeared after elution, and the peak value increased significantly after elution. The larger the current value, the more cavities there are on the imprinted membrane, which once again verifies that the template molecules are eluted.

[0048] 2. Concentration response curve and linear relationship of molecular imprinting electrochemical sensor

[0049] In the three-electrode system, the eluted molecular imprinted electrode was used as the working electrode, the counter electrode was a graphite electrode, and the reference electrode was a silver / silver chloride electrode. The electrodes were electrochemically characterized by square wave voltammetry, see Figure 3 In the figure a, the square wave voltammogram of the imprinted electrode under different concentrations of serotonin is shown; when constructing the calibration curve, different concentrations of serotonin are used as the abscissa and the corresponding peak current is used as the ordinate.

[0050] like Figure 3 As shown, by comparison, it can be verified that after elution, the imprinted electrode surface leaves holes that specifically bind to the molecular structure of serotonin. As the concentration of serotonin increases, the imprinted holes are gradually filled, resulting in a decrease in the concentration of effective probe ions reaching the electrode surface, a decrease in the electrical signal, and a decrease in the peak current. When the serotonin concentration reaches a certain value, the peak current no longer changes, which may be because the imprinted membrane holes on the electrode have been completely filled. A linear fit is performed between the serotonin concentration and the peak current value. Figure 3 b in the figure is: the linear relationship between the peak current and the concentration of serotonin in the range of 0.05 to 6 μM, and the linear equation is I 五羟色胺 =-7.21C+172(R 2 =0.9920).

[0051] 3. Another important indicator of the sensor: detection specificity

[0052] In order to verify the selectivity and anti-interference ability of the molecular imprinting electrochemical sensor of the present invention, dopamine, adrenaline, glucose and sodium chloride were selected as interfering substances. The electrochemical responses of the sensor to serotonin and interfering substances were investigated in a PBS buffer solution with a pH value of 6.8 (the results are shown in FIG. Figure 4The results show that in the presence of interfering substances, the sensor's response peak current changes very little, showing poor selectivity. However, when serotonin is added, the sensor's current response difference is significantly higher than that of other interfering substances, indicating that the sensor has high recognition ability and specificity for serotonin.

[0053] In summary, the present invention successfully prepared a MoS2-Ti / Au modified PET thin film electrode molecular imprinting electrochemical sensor, which can quickly and efficiently detect the target serotonin. The modification of MoS2-Ti / Au improves the conductivity of the sensor, thereby enhancing the sensitivity and stability. Through the fixed modification of template molecules and functional monomers, ultra-sensitive and highly specific detection of serotonin, a marker of neurological diseases, is achieved. In addition, the preparation process of the sensor is simple, the detection operation is convenient, and it has the advantages of rapidity, efficiency and accuracy, which is conducive to commercial application.

[0054] 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 modifications or variations within the scope of the claims, which will not affect the essence of the present invention.

Claims

1. A method for preparing a MoS2-Ti / Au modified PET thin film electrode molecular imprinting electrochemical sensor, characterized in that: The following steps are involved: Step 1, preparation of MoS2-Ti / Au electrode material: slice the PET film, clean and dry it, sputter Ti and Au metals, and coat the MoS2 film on the electrode surface; Step 2, preparing a Prussian blue solution: mixing FeCl3, K3[Fe(CN)6], KCl, and PBS solution, and stirring; Step 3, prepare pyrrole solution: dissolve 100 μL of monopyrrole solution in 5 mL of ethanol and stir until fully dissolved; Step 4, preparing a molecular polymerization solution: dissolving the template molecule in 5 mL of water, adding a PBS solution, and then adding a Prussian blue solution and a pyrrole solution, stirring, standing, and taking the supernatant to obtain a molecular polymerization solution; Step 5, electropolymerization reaction: immersing the MoS2-Ti / Au electrode material in a molecular polymerization solution, depositing it on the surface of the electrode substrate by cyclic voltammetry to form a molecular imprinting film, polymerizing, and obtaining a polymerized MIP electrode; Step 6, eluting the polymerized MIP electrode to wash away the template molecules on the molecular imprinting membrane to obtain a MoS2-Ti / Au modified PET thin film electrode molecular imprinting electrochemical sensor.

2. The method for preparing a MoS2-Ti / Au modified PET thin film electrode molecular imprinting electrochemical sensor according to claim 1, characterized in that: In step 1, the specific steps of preparing the MoS2-Ti / Au electrode material are: (1) Slice the PET film, clean it ultrasonically in an ethanol solution, soak it in deionized water, and blow dry it with N2; (2) Using magnetron sputtering technology, Ti and Au metals are sputtered sequentially in a sputtering chamber; (3) Use a micropipette to drop the MoS2 suspension onto the surface of the PET electrode containing Ti / Au, and let it stand at room temperature to fully dry to form a uniform film on the surface of the PET electrode.

3. The method for preparing a MoS2-Ti / Au modified PET thin film electrode molecular imprinting electrochemical sensor according to claim 2, characterized in that: The thicknesses of the Ti and Au metals are 5 nm and 40 nm respectively.

4. The method for preparing a MoS2-Ti / Au modified PET thin film electrode molecular imprinting electrochemical sensor according to claim 1, characterized in that: In step 2, the preparation method of the Prussian blue solution is as follows: first, 10 mM FeCl3, 10 mM K3[Fe(CN)6], 10 mM KCl, and 5 mM PBS solution are mixed, and stirred at a speed of 400 rpm to prepare the solution.

5. The method for preparing a MoS2-Ti / Au modified PET thin film electrode molecular imprinting electrochemical sensor according to claim 1, characterized in that: In step 3, the stirring is carried out by using a magnetic stirrer.

6. The method for preparing a MoS2-Ti / Au modified PET thin film electrode molecular imprinting electrochemical sensor according to claim 1, characterized in that: In step 4, the concentration ratio of the Prussian blue solution, the pyrrole solution and the template molecule is 1:10:1; the stirring is performed by a magnetic stirrer for 40 minutes.

7. The method for preparing a MoS2-Ti / Au modified PET thin film electrode molecular imprinting electrochemical sensor according to claim 1, characterized in that: In step 5, the electropolymerization reaction is carried out in a three-electrode system, the working electrode is a MoS2-Ti / Au electrode, the counter electrode is a graphite electrode, and the reference electrode is a silver / silver chloride electrode; the deposition liquid is a molecular imprinting polymerization solution.

8. The method for preparing a MoS2-Ti / Au modified PET thin film electrode molecular imprinting electrochemical sensor according to claim 1, characterized in that: In step 6, the specific method of elution is: immersing the polymerized MIP electrode in a PBS buffer solution, eluting by square wave voltammetry at different frequencies in a potential range of -0.3 to 1.1 V, and the elution times are 8 to 15 times.

9. An application of a MoS2-Ti / Au modified PET thin film electrode molecular imprinting electrochemical sensor, characterized in that: The MoS2-Ti / Au modified PET thin film electrode molecular imprinting electrochemical sensor prepared according to claim 1 is used for selective detection of serotonin.

10. The use of the MoS2-Ti / Au modified PET thin film electrode molecular imprinting electrochemical sensor as claimed in claim 9, characterized in that: The process of detecting serotonin is: immersing the polymerized MIP electrode in claim 1 into a PBS buffer solution, adding serotonin of different concentrations in sequence, and detecting its electrochemical response by using the SWV method.

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