A preparation method of a flexible sensor electrode loaded with nanoparticles in situ

Abstract

The application relates to a preparation method of a flexible sensing electrode loaded with nanoparticles in situ, belonging to the flexible sensing field. Mainly comprising the following steps: (1) mixing a conductive polymer complex and a metal acid, improving the conductivity by inducing the rearrangement of the conductive polymer chain through the protonation of the polyanion of the metal acid, and generating metal nanoparticles by in-situ limiting reduction of the metal acid of the conductive polymer, so as to cooperatively prepare a flexible high-performance hydrogen peroxide sensing electrode; (2) adding ethylene glycol into the conductive polymer complex solution to improve the solution viscosity and limit the aggregation of the metal nanoparticles; and (3) coating the mixed solution of the conductive polymer complex and the metal acid on a flexible substrate to prepare a flexible hydrogen peroxide sensing electrode. The prepared flexible sensing electrode has high sensitivity and can be used for detecting the hydrogen peroxide concentration.

Description

Technical fields:

[0001] This invention prepares a flexible sensing electrode uniformly loaded with nanoparticles by simultaneously coupling noble metal acid-induced chain segment rearrangement of conductive polymer and in-situ reduction of noble metal acid by conductive polymer to generate nanoparticles. It is used for hydrogen peroxide sensing in life and metabolic processes and belongs to the field of flexible sensing. Background technology:

[0002] Hydrogen peroxide is a reactive oxygen species carrier in various biochemical reactions and a product of enzymatic reactions in biomolecules, such as glucose, lactic acid, and cholesterol. Therefore, the concentration of hydrogen peroxide in the body serves as a diagnostic indicator for cardiovascular diseases, neurological disorders, cancer, and diabetes. Real-time monitoring of hydrogen peroxide concentration and that produced by enzymatic reactions in the human body is of great significance for the diagnosis and prevention of related diseases.

[0003] Traditional medical testing typically employs large-scale analytical equipment, which is expensive, bulky, time-consuming, and requires professional operation, making it unsuitable for home use. Therefore, the development of miniaturized, easy-to-operate, flexible, and inexpensive hydrogen peroxide sensing electrodes has become a current need. Electrochemical hydrogen peroxide sensors catalyze the oxidation reaction of catalase using a loaded catalase electrode, generating a redox current to obtain the hydrogen peroxide concentration. Its simple operation and ease of miniaturization meet the aforementioned requirements. However, the activity of enzyme electrodes is easily affected by external factors such as temperature, oxygen content, pH value, and other chemical substances. Therefore, the development of enzyme-free, high-performance hydrogen peroxide sensing electrodes holds great promise for advancing real-time medical testing.

[0004] Loading stable and efficient metal nanoparticle catalysts onto sensing electrodes to achieve the catalytic oxidation of hydrogen peroxide can improve the stability and detection sensitivity of the sensing electrodes. Currently, methods for loading metal nanoparticles onto electrodes mainly include direct blending (Pedro JL, Biosensors and Bioelectronics, 2014, 56, 345–351) and electrochemical deposition (Zhang YY, Analytical Chemistry, 2014, 86, 9459-9465). Direct blending results in poor dispersion of the metal nanoparticles, while electrodeposition produces larger particle sizes. Both methods reduce the specific surface area of ​​the metal nanoparticles, decrease the number of catalytically active sites, and lead to a decrease in sensor sensitivity. Furthermore, flexible conductive polymers can be used as supports for metal nanoparticles to prepare flexible sensing electrodes; however, the low conductivity of conductive polymers hinders electron interfacial transport, reducing sensor sensitivity and response time.

[0005] This invention proposes an in-situ confined reaction strategy, utilizing a strongly acidic noble metal acid to induce structural rearrangement of conductive polymer chains, thereby improving their conductivity. Simultaneously, the conductive polymer undergoes in-situ confined reduction of the noble metal acid to generate metal nanoparticles. This achieves simultaneous polymer chain rearrangement and uniform metal nanoparticle generation, resulting in a flexible hydrogen peroxide sensing electrode loaded with uniformly dispersed small-diameter metal nanoparticles. This flexible hydrogen peroxide sensor possesses advantages such as wearability, high sensitivity, miniaturization, easy integration, wide detection range, and easy signal extraction. It provides a new method for fabricating high-performance flexible wearable hydrogen peroxide sensors and has significant practical implications for developing wearable sensor devices, advancing smart healthcare, and alleviating medical pressure. Summary of the Invention:

[0006] The purpose of this invention is to prepare a flexible, highly sensitive hydrogen peroxide sensor for human health monitoring. An in-situ confined reaction strategy is employed to uniformly dissolve a noble metal acid and a conductive polymer complex in an aqueous ethylene glycol (EG) solution and spin-coat a flexible catalytic electrode film. The protonated polyanions of the noble metal acid promote the rearrangement (recrystallization) of the conductive polymer chains, improving the electrode's conductivity. Simultaneously, the conductive polymer undergoes in-situ confined reduction of the noble metal acid to obtain uniformly dispersed small-particle metal nanoparticles (approximately 4 nm). This results in a flexible hydrogen peroxide sensing electrode with metal nanoparticles uniformly loaded onto the conductive polymer complex, used for highly sensitive and stable detection of hydrogen peroxide concentration.

[0007] The fabrication of a flexible hydrogen peroxide sensing electrode based on a conductive polymer complex loaded with metal nanoparticles involves the following steps:

[0008] (1) A conductive polymer complex aqueous dispersion (mass fraction 1%-2%) is uniformly mixed with ethylene glycol (EG) to obtain a solution with a certain viscosity (EG volume fraction 5%-50%). Then, a surfactant (Triton X-100) (volume fraction 0.4%-4%) is added to the above solution and stirred thoroughly.

[0009] (2) Dissolve the noble metal acid in the solution obtained in step (1) (concentration: 20-100mM) and stir until the mixture is homogeneous;

[0010] (3) After cleaning the flexible and dense substrate, perform hydrophilic modification (including hydrophilic modification using oxygen plasma);

[0011] (4) Spin coat the mixed solution after step (2) onto the substrate of step (3), and then anneal it on a heating table for 15 minutes;

[0012] (5) Wash and dry the annealed substrate in step (4) to obtain a flexible hydrogen peroxide sensing electrode loaded with conductive polymer complex of metal nanoparticles.

[0013] The conductive polymer complex is formed by electrostatic complexation of a conductive polymer and a polyanion, wherein the conductive polymer has a long chain with π conjugation, such as PEDOT, PEDOT, polyaniline (PANI), etc.

[0014] The noble metal acid mentioned is selected from H2PtCl6, HAuCl4, PdCl2, etc.

[0015] The flexible and dense substrate is selected from polyimide (PI), PET, etc.

[0016] The evaluation steps for the flexible hydrogen peroxide sensing electrode supported on conductive polymer complexes by metal nanoparticles are as follows:

[0017] (a) The mixed solution in step (2) was spin-coated onto a quartz plate modified by oxygen plasma hydrophilicity. After annealing, washing and drying, the conductivity was tested using a four-probe conductivity meter.

[0018] (b) The film from step (a) was peeled off from the substrate and its loading and distribution of metal nanoparticles were characterized by transmission electron microscopy.

[0019] (c) Connect the electrode from preparation step (5) to an electrochemical workstation. Use the flexible electrode of conductive polymer complex supported by metal nanoparticles as the working electrode, Ag / AgCl as the reference electrode, and glassy carbon electrode (GCE) as the counter electrode. Place the electrode in an electrochemical cell and apply a constant voltage (-0.2 to -0.5V). Gradually add hydrogen peroxide of different concentrations and test its chronocurrent curve. Then, detect the current of the analyte and compare it with the chronocurrent curve to obtain the concentration.

[0020] Technical Principles of the Invention

[0021] This invention employs a conductive polymer complex as the flexible electrode material, which is formed by electrostatic complexation of a conductive polymer and a polyanion. A strong acidic noble metal is added to the dispersion of the conductive polymer complex, protonating the polyanion and weakening its electrostatic interaction with the conductive polymer. This promotes the recrystallization of the conductive polymer segments through π-π interactions, thereby increasing the electrode's conductivity. Simultaneously, the conductive polymer reduces the noble metal acid in situ within the confines of EG (electromagnetic oxide) to generate uniformly dispersed metal nanoparticles (approximately 4 nm in diameter), increasing active sites and catalyzing the hydrogen peroxide electrode reaction. Therefore, the increased conductivity of the flexible electrode (promoting electron transport) and the increased active sites of the metal nanoparticles (enhancing catalytic efficiency) synergistically improve the sensitivity of the flexible hydrogen peroxide sensor and lower the detection limit, achieving highly sensitive and stable detection of hydrogen peroxide concentration. Attached image description:

[0022] Figure 1X-ray diffraction patterns of the conductive polymer complex poly(3,4-ethylenedioxythiophene monomer):polystyrene sulfonate (PEDOT:PSS) before and after the addition of chloroplatinic acid. The appearance of new diffraction peaks after the addition of chloroplatinic acid indicates that the conductive polymer has undergone recrystallization.

[0023] Figure 2 To investigate the effect of adding different concentrations of H2PtCl6 to PEDOT:PSS dispersion on the conductivity of PEDOT:PSS;

[0024] Figure 3 Transmission electron microscopy image of PEDOT:PSS;

[0025] Figure 4 Transmission electron microscopy image of PEDOT:PSS loaded with platinum nanoparticles (PtNP);

[0026] Figure 5 The PEDOT:PSS (PtNP@PEDOT:PSS) sensing electrode is spin-coated onto a polyethylene terephthalate (PET) substrate and loaded with platinum nanoparticles.

[0027] Figure 6 The graph shows the performance of the PtNP@PEDOT:PSS flexible sensing electrode in Example 1.

[0028] Figure 7 The graph shows the GCE sensing performance of the load PtNP@PEDOT:PSS in Example 2. Detailed Implementation

[0029] The present invention will be described in detail below with reference to specific examples, but the present invention is not limited to the following examples.

[0030] Example 1

[0031] (1) PEDOT: PSS dispersion (mass fraction 1.1%-1.6%, commercially available) is uniformly mixed with EG to obtain a solution with a certain viscosity (EG volume fraction 10%). Then, Triton X-100 (volume fraction 0.4%) is added to the above solution and stirred thoroughly with a magnetic stirrer.

[0032] (2) Dissolve H2PtCl6 in the solution described in (1) (concentration: 60mM) and stir until the mixture is homogeneous;

[0033] (3) The PET substrate was cleaned with ethanol and then hydrophilic modified with oxygen plasma;

[0034] (4) Spin-coat the mixed solution after stirring in (1) and (2) onto the PET substrate described in (3) and then anneal it on a heating table at 120°C for 15 minutes.

[0035] (5) Wash and dry the annealed PET described in (4) to obtain PtNP@PEDOT:PSS flexible hydrogen peroxide sensing electrode based on PET and PEDOT:PSS flexible hydrogen peroxide sensing electrode without chloroplatinic acid.

[0036] (6) Connect the two PET substrate flexible hydrogen peroxide sensing electrodes obtained in (5) to an electrochemical workstation as the working electrode, Ag / AgCl as the reference electrode, and GCE as the counter electrode to form a three-electrode system. Place them in an electrochemical cell and apply a constant voltage of -0.5V. Gradually add hydrogen peroxide of different concentrations to test its response current. Plot the concentration-current response curves of PtNP@PEDOT:PSS flexible hydrogen peroxide sensing electrode and PEDOT:PSS flexible hydrogen peroxide sensing electrode.

[0037] The results show that the PtNP@PEDOT:PSS-PET flexible hydrogen peroxide sensing electrode loaded with PtNP can sensitively detect hydrogen peroxide concentration, with a sensitivity of 5.05 μA mM. -1 cm -2 (And the lowest detection limit is 0.69 mM), compared to the PEDOT:PSS flexible sensor's sensitivity of 0.575 μA mM. -1 cm -2 (Lowest detection limit 5.9mM) improved by nearly 9 times; sensitivity test results are shown below. Figure 6 .

[0038] Example 2

[0039] (1) PEDOT: PSS dispersion (mass fraction 1.1%-1.6%, commercially available) is uniformly mixed with EG to obtain a solution with a certain viscosity (EG volume fraction 10%). Then, Triton X-100 (volume fraction 0.4%) is added to the above solution and stirred thoroughly with a magnetic stirrer.

[0040] (2) Dissolve H2PtCl6 in the solution described in (1) (concentration: 60mM) and stir until the mixture is homogeneous;

[0041] (3) GCE was polished with alumina powder and then cleaned, and then hydrophilic modified with oxygen plasma.

[0042] (4) Add the solution obtained in (2) to the GCE described in (3) and anneal in an oven at 120°C for 15 minutes;

[0043] (5) Wash and dry the annealed GCE described in (4) to obtain the PtNP@PEDOT:PSS hydrogen peroxide sensing electrode.

[0044] (6) Connect the PtNP@PEDOT:PSS hydrogen peroxide sensing electrode and GCE obtained in (5) to an electrochemical workstation as the working electrode, Ag / AgCl as the reference electrode and GCE as the counter electrode to form a three-electrode system. Place it in an electrochemical cell and apply a constant voltage of -0.5V. Add hydrogen peroxide of different concentrations to test its response current. Plot the hydrogen peroxide concentration-current response curves of PtNP@PEDOT:PSS hydrogen peroxide sensing electrode and GCE respectively.

[0045] The results show that the PtNP@PEDOT:PSS hydrogen peroxide sensing electrode can sensitively detect hydrogen peroxide concentration, with a sensitivity significantly higher than that of the GCE electrode (more than 10 times), reaching a sensitivity of 2346.8 μA mM. -1 cm -2 Test results are available Figure 7 And the minimum detection limit is 0.1mM.

[0046] Example 3

[0047] (1) PEDOT: PSS dispersion (mass fraction 1.1%-1.6%, commercially available) is uniformly mixed with EG to obtain a solution with a certain viscosity (EG volume fraction 10%). Then, Triton X-100 (volume fraction 0.4%) is added to the above solution and stirred thoroughly with a magnetic stirrer.

[0048] (2) Dissolve HAuCl4 in the solution described in (1) (concentration: 60mM) and stir until the mixture is homogeneous;

[0049] (3) The PET substrate was cleaned with ethanol and then hydrophilic modified with oxygen plasma;

[0050] (4) Spin-coat the mixed solution after stirring in (2) onto the PET substrate described in (3), and then anneal it on a heating table at 120°C for 15 minutes;

[0051] (5) Wash and dry the annealed PET described in (4) to obtain AuNP@PEDOT:PSS flexible hydrogen peroxide sensing electrode based on PET.

[0052] (6) Connect the AuNP@PEDOT:PSS flexible hydrogen peroxide sensing electrode obtained in (5) to an electrochemical workstation as the working electrode, Ag / AgCl as the reference electrode, and GCE as the counter electrode to form a three-electrode system. Place it in an electrochemical cell and apply a constant voltage of -0.5V. Add hydrogen peroxide of different concentrations to test its response current and plot the hydrogen peroxide concentration-response current curve of the sensing electrode.

[0053] Example 4

[0054] (1) PEDOT: PSS dispersion (mass fraction 1.1%-1.6%, commercially available) is uniformly mixed with EG to obtain a solution with a certain viscosity (EG volume fraction 10%). Then, Triton X-100 (volume fraction 0.4%) is added to the above solution and stirred thoroughly with a magnetic stirrer.

[0055] (2) Dissolve PdCl2 in a small amount of concentrated hydrochloric acid (PdCl2 concentration: 15M), and then dissolve it in (1).

[0056] Prepare a PdCl2 solution with a concentration of 60 mM in the solution described above, and stir until the mixture is uniform; (3) Clean the PET substrate with ethanol and perform hydrophilic modification with oxygen plasma;

[0057] (4) Spin-coat the mixed solution after stirring in (2) onto the PET substrate described in (3), and then anneal it on a heating table at 120°C for 15 minutes;

[0058] (5) Wash and dry the annealed PET described in (4) to obtain a PbNP@PEDOT:PSS flexible hydrogen peroxide sensing electrode based on PET.

[0059] (6) Connect the PbNP@PEDOT:PSS flexible hydrogen peroxide sensing electrode obtained in (5) to an electrochemical workstation as the working electrode, Ag / AgCl as the reference electrode and GCE as the counter electrode to form a three-electrode system. Place it in an electrochemical cell and apply a constant voltage of -0.5V. Add hydrogen peroxide of different concentrations to test its response current and plot the hydrogen peroxide concentration-current response curve of the sensing electrode.

[0060] Example 5

[0061] (1) PEDOT:tos dispersion (mass fraction 1.1%-1.6%, commercially available) is mixed with EG to obtain a solution with a certain degree of viscosity (EG volume fraction 10%). Then, Triton X-100 (volume fraction 0.4%) is added to the above solution and stirred thoroughly with a magnetic stirrer.

[0062] (2) Dissolve H2PtCl6 in the solution described in (1) (concentration: 60mM) and stir until the mixture is homogeneous;

[0063] (3) The PET substrate was cleaned with ethanol and then hydrophilic modified with oxygen plasma;

[0064] (4) Spin-coat the mixed solution after stirring in (2) onto the PET substrate described in (3), and then anneal it on a heating table at 120°C for 15 minutes;

[0065] (5) Wash and dry the annealed PET described in (4) to obtain a flexible hydrogen peroxide sensing electrode based on PET, namely PtNP@PEDOT:tos.

[0066] (6) Connect the PtNP@PEDOT:tos flexible hydrogen peroxide sensing electrode obtained in (5) to an electrochemical workstation as the working electrode, Ag / AgCl as the reference electrode and GCE as the counter electrode to form a three-electrode system. Place it in an electrochemical cell and apply a constant voltage of -0.5V. Add hydrogen peroxide of different concentrations to test its response current and plot the hydrogen peroxide concentration-current response curve of the sensing electrode.

[0067] Example 6

[0068] (1) Mix PANI:PSS dispersion (mass fraction 1.1%-1.6%, commercially available) with EG to obtain a solution with a certain degree of stability (EG volume fraction 10%). Then add Triton X-100 (volume fraction 0.4%) to the above solution and stir thoroughly with a magnetic stirrer.

[0069] (2) Dissolve H2PtCl6 in the solution described in (1) (concentration: 60mM) and stir for at least 10 minutes until the mixture is homogeneous;

[0070] (3) The PET substrate was cleaned with ethanol and then hydrophilic modified with oxygen plasma;

[0071] (4) Spin-coat the mixed solution after stirring in (2) onto the PET substrate described in (3), and then anneal it on a heating table at 120°C for 15 minutes;

[0072] (5) Wash and dry the annealed PET described in (4) to obtain a PtNP@PANI:PSS flexible hydrogen peroxide sensing electrode based on PET.

[0073] (6) Connect the PtNP@PANI:PSS flexible hydrogen peroxide sensing electrode obtained in (5) to an electrochemical workstation as the working electrode, Ag / AgCl as the reference electrode, and GCE as the counter electrode to form a three-electrode system. Place it in an electrochemical cell and apply a constant voltage of -0.5V. Add hydrogen peroxide of different concentrations to test its response current and plot the hydrogen peroxide concentration-current response curve of the sensing electrode.

Claims

1. A method for preparing an in-situ loaded nanoparticle flexible sensing electrode, characterized in that, Includes the following steps: (1) A conductive polymer complex aqueous dispersion is uniformly mixed with ethylene glycol (EG) to obtain a solution with a certain viscosity. Then, the surfactant Triton X-100 is added to the above solution and stirred thoroughly. (2) Dissolve the noble metal acid in the solution obtained in step (1) and stir until the mixture is homogeneous; (3) After cleaning the flexible and dense substrate, hydrophilic modification is performed; (4) Spin coat the mixed solution after step (2) onto the substrate of step (3), and then anneal it on a heating table for 15 minutes; (5) Wash and dry the substrate after annealing in step (4) to obtain a flexible hydrogen peroxide sensing electrode loaded with conductive polymer complex of metal nanoparticles. The conductive polymer complex is formed by electrostatic complexation of a conductive polymer and a polyanion, wherein the conductive polymer has a long chain with π-conjugation.

2. The method for preparing an in-situ loaded nanoparticle flexible sensing electrode according to claim 1, characterized in that, The conductive polymer complex is selected from PEDOT:PSS, PEDOT:Tos, or PANI:PSS.

3. The method for preparing an in-situ loaded nanoparticle flexible sensing electrode according to claim 1, characterized in that, The noble metal acid is selected from H2PtCl6, HAuCl4, and PdCl2.

4. The method for preparing an in-situ loaded nanoparticle flexible sensing electrode according to claim 1, characterized in that, The flexible, dense substrate is selected from polyimide (PI) and PET.

5. The method for preparing an in-situ loaded nanoparticle flexible sensing electrode according to claim 1, characterized in that, The complex aqueous dispersion has a mass fraction of 1%-2%, EG has a volume fraction of 5%-50%, and then the surfactant Triton X-100 has a volume fraction of 0.4%-4% added to the above solution.

6. The method for preparing an in-situ loaded nanoparticle flexible sensing electrode according to claim 1, characterized in that, The concentration of the noble metal acid in step (2) is 20-100 mM.

7. The method for preparing an in-situ loaded nanoparticle flexible sensing electrode according to claim 1, characterized in that, Step (3) hydrophilic modification includes hydrophilic modification using oxygen plasma.

8. The method for preparing an in-situ loaded nanoparticle flexible sensing electrode according to claim 1, characterized in that, Step (4) Annealing temperature 120℃.

9. An in-situ loaded nanoparticle flexible sensing electrode prepared by the method according to any one of claims 1-8.

10. The application of an in-situ loaded nanoparticle flexible sensing electrode prepared by the method according to any one of claims 1-8, for the detection of hydrogen peroxide.

11. In the application according to claim 10, the electrode is connected to an electrochemical workstation, the flexible electrode of conductive polymer complex supported by metal nanoparticles is used as the working electrode, Ag / AgCl is used as the reference electrode, and glassy carbon electrode (GCE) is used as the counter electrode. The electrode is placed in an electrochemical cell and a constant voltage of -0.2 to -0.5V is applied. Hydrogen peroxide of different concentrations is gradually added to test its chronocurrent curve. Then, the current of the analyte is detected and the concentration is obtained by comparing it with the chronocurrent curve.

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