Three-electrode integrated photoelectrochemical microelectrode and preparation method thereof
By integrating the working electrode, reference electrode and counter electrode in the nanotube electrode, the problems of polarization and solution voltage drop in the existing two-electrode system are solved, and high accuracy detection of trace substances in a single cell is achieved.
Patent Information
- Application Number
- CN202510137298.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-07
- Publication Date
- 2025-05-09
AI Technical Summary
The existing nanopipe detection devices are usually separate two-electrode systems, with problems with polarization and solution voltage drop, resulting in inaccurate test results and possible damage to target cells.
By chemically reducing the platinum layer as the counter electrode on the inner wall of the nanotube electrode, photoelectroactive materials as working electrodes are synthesized on the outer wall of the nanotube electrode, and Ag/AgCl wire reference electrode is assembled into the nanotube electrode to achieve the preparation of three-electrode integrated photoelectrochemical microelectrodes.
In-situ electrochemical detection of trace substances in a single cell is achieved, which enhances anti-interference ability, reduces test errors, and improves detection accuracy and safety.
Smart Images
Figure CN119959321A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of electrochemical analysis and also relates to the field of micro-nano structure processing, and specifically relates to a method for preparing a three-electrode integrated photoelectrochemical microelectrode. Background Art
[0002] Conventional cell analysis techniques only reflect the average information of cell populations, masking their individual differences and failing to provide detailed information at the level of individual cells, which is particularly insufficient when studying cell heterogeneity and disease microenvironment. Single-cell analysis technology allows for precise analysis of individual cells without destroying the normal state of the cells, thereby revealing subtle changes within the cells and even predicting the development trend of the disease. Photoelectrochemistry is a cutting-edge analytical technology that avoids background interference in traditional electrochemical methods and improves detection sensitivity due to the separation of the excitation light source and the detection signal. The easy miniaturization of photoelectrochemistry makes it more compatible with living organisms and is expected to open up new research avenues for single-cell analysis.
[0003] Nanotube electrodes exhibit excellent temporal and spatial resolution due to their easy manufacturing and controllable properties, as well as the advantage of minimal interference to cells. By functionalizing them through physical or chemical modification and integrating different technologies, they can further meet the requirements of intracellular operations and are widely used in the field of single-cell analysis. Existing nanopipette detection devices are usually separate two-electrode systems, in which a functionalized nanotube is connected by a wire as a working electrode to form a loop with a reference electrode located in an external buffer solution. Although the two-electrode system has made progress in the field of single-cell analysis, it still has certain limitations. For example, the electrode is prone to polarization, resulting in potential changes, and there is a problem of solution voltage drop in the system itself. These limitations reduce the accuracy of the test results and even cause damage to the target cells. Therefore, it is particularly important to propose a method for preparing a three-electrode integrated photoelectrochemical microelectrode device.
[0004] The three-electrode integrated nano-microelectrode integrates the working electrode, reference electrode and counter electrode into a nanotube. The working electrode and counter electrode form an electrode loop to test the actual reaction, and the reference electrode provides a potential reference to ensure measurement accuracy. Through precise potential control, the three-electrode integrated nanotube microelectrode not only has strong anti-interference ability, but also can effectively avoid the problems of the two-electrode system itself, reduce test errors, and realize in-situ testing inside cells. Summary of the invention
[0005] To solve the above problems, the present invention discloses a three-electrode integrated photoelectrochemical microelectrode and a preparation method thereof, wherein a platinum layer is synthesized by chemical reduction on the inner wall of a nanotube electrode as a counter electrode, a photoelectrically active material is synthesized on the outer wall of the nanotube electrode as a working electrode, and an Ag / AgCl wire reference electrode is assembled into the nanotube electrode, thereby realizing the preparation of a three-electrode integrated photoelectrochemical microelectrode.
[0006] The specific plan is as follows: A three-electrode integrated photoelectrochemical microelectrode comprises an Ag / AgCl wire, a silver wire, a borosilicate nanotube, a metal platinum film on the outer wall of the nanotube, a copper wire, a metal platinum layer on the inner wall of the nanotube and a photoelectrically active material; one end of the Ag / AgCl wire axially extends into the borosilicate nanotube, and the silver wire portion outside the borosilicate nanotube serves as an electrode pin and is connected to a reference electrode loop; one end of the silver wire axially extends into the borosilicate nanotube and contacts the metal platinum layer on the inner wall of the nanotube, and the other end is connected to a counter electrode loop; one end of the copper wire is wound around the metal platinum film on the outer wall of the nanotube and is connected to the photoelectrically active material electroplated on the metal platinum film on the outer wall of the nanotube, and the other end is connected to a working electrode loop, thereby obtaining a three-electrode integrated photoelectrochemical microelectrode.
[0007] A method for preparing a three-electrode integrated photoelectrochemical microelectrode, the steps are as follows: Step 1: Preparation of nanotube electrodes: The cleaned borosilicate capillary was drawn into a nanotube electrode by a laser drawing instrument.
[0008] Step 2: Prepare the platinum layer on the inner wall of the nanotube: 3-Aminopropyltriethoxysilane (APTES) solution and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) (PEDOT:PSS) solution are injected into the nanotube electrode in sequence and maintained for a period of time. The solutions are then removed from the nanotube electrode by centrifugation, and a mixed solution of chloroplatinic acid (H2PtCl6) and ethylene glycol (EG) is injected and maintained at a certain temperature for a period of time to obtain a platinum layer on the inner wall of the nanotube electrode.
[0009] Step 3: Preparation of photoelectrically active materials: Taking Cu2O as an example, the electroplating method for preparing photoelectric active materials is introduced: a layer of platinum film is sputtered on the outer wall of the nanotube electrode by magnetron sputtering and then placed in a box furnace for annealing. Then, anhydrous copper acetate (Cu(CH3COO)2) and anhydrous sodium acetate (CH3COONa) are mixed by vigorous stirring. The annealed nanotube electrode is immersed in the mixed solution and electroplated to synthesize the Cu2O photoelectric active material.
[0010] Step 4: Preparation of Ag / AgCl wire: A silver wire with a diameter of 0.8 mm was placed in a sodium hypochlorite (NaClO) solution and allowed to stand for 30 min. It was then washed with ultrapure water. A cellulose acetate (CA) solution was wrapped around the top of the Ag / AgCl wire. The part not in contact with the cellulose acetate film was insulated, and a portion of the silver wire was retained for connecting the circuit.
[0011] Step 5: Assemble the three-electrode integrated photoelectrochemical microelectrode: Copper wire is used to connect the Cu2O photoelectric active material on the platinum film on the outer wall of the nanotube electrode, and silver wire is used to connect the platinum layer on the inner wall of the nanotube. Finally, Ag / AgCl wire is extended into the nanotube to form a three-electrode integrated photoelectrochemical microelectrode.
[0012] Furthermore, in step 1, the borosilicate capillary is immersed in a mixed solution of concentrated sulfuric acid (H2SO4): 30% hydrogen peroxide (H2O2) = 3:1 for 1 h, washed with ultrapure water and then dried in a vacuum environment at 80°C.
[0013] Furthermore, in step 1, the nanotube electrode is drawn by a laser drawing apparatus, and the specific parameters used are set as HEAT=380, FIL=1, VEL=10, DEL=145, and PULL=180.
[0014] Furthermore, in step 2, 10 μL of 9.1% APTES ethanol (C2H5OH) solution was injected into the nanotube electrode, reacted at room temperature for 10 min, then the solution was removed by centrifugation and vacuum dried at 60°C for 30 min, then 10 μL of PEDOT:PSS methanol (CH3OH) solution was injected into the nanotube electrode, reacted at room temperature in the dark for 30 min, then the solution was removed by centrifugation and vacuum dried at 110°C for 30 min, then 10 μL of 25 mM H2PtCl6 and EG mixed solution was injected into the nanotube electrode, reacted at 120°C for 1 h, and after the reaction, the excess solution was removed from the nanotube electrode by centrifugation to obtain a platinum layer.
[0015] Furthermore, in step 2, PEDOT:PSS and CH3OH are prepared in a volume ratio of 1:1 to form a PEDOT:PSS CH3OH solution.
[0016] Furthermore, in step 2, the centrifugal speed is 11800 rpm.
[0017] Furthermore, in step 3, a platinum target is used in the magnetron sputtering process, the sputtering current is 100 mA, and the time is 300 s.
[0018] Further, in step 3, annealing is performed in a box furnace at 80° C. for 1 h.
[0019] Furthermore, in step 3, the plating solution was prepared by dissolving 41.01 mg CH3COONa and 181.65 mg Cu(CH3COO)2 in 50 ml ultrapure water and vigorously stirring for 15 min.
[0020] Furthermore, in step 3, the voltage applied during the electroplating process is -0.2 V and the time is 20 s.
[0021] Furthermore, in step 4, the CA solution is prepared by dissolving 1500 mg of CA in 3 mL of acetic acid (CH3COOH).
[0022] Beneficial effects of the present invention: The present invention integrates three electrodes into a nanotube electrode device, with a simple process and strong repeatability. Due to the integration of the complete three electrodes, it is expected to realize in situ electrochemical detection of trace substances in a single cell, and broaden the application of nanotube electrode devices in single-cell detection and analysis. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 This is a schematic diagram of the microelectrode preparation described in Example 1; Figure 2 This is a schematic diagram of the structure of the microelectrode assembly described in Example 1; Figure 3 This is the appearance diagram of the microelectrode described in Example 1; Figure 4 The microelectrode cyclic voltammetry (CV) test graphs described in Example 2, wherein a is a CV graph of bare indium tin oxide (ITO) as a working electrode, a commercial reference electrode and a commercial counter electrode, b is a CV graph of bare ITO as a working electrode, Ag / AgCl wire as a reference electrode and a commercial counter electrode, c is a CV graph of bare ITO as a working electrode, a commercial reference electrode and platinum on the inner wall of the nanotube as a counter electrode, and d is a CV graph of a three-electrode integrated photoelectrochemical microelectrode; Figure 5 This is the photoelectric response diagram of the microelectrode described in Example 3, where a is the photoelectric response of Cu2O as the working electrode, the commercial reference electrode and the commercial counter electrode, b is the photoelectric response of Cu2O as the working electrode, Ag / AgCl wire as the reference electrode and the commercial counter electrode, c is the photoelectric response of Cu2O as the working electrode, the commercial reference electrode and the platinum on the inner wall of the nanotube as the counter electrode, and d is the photoelectric response of the three-electrode integrated photoelectrochemical microelectrode.
[0024] List of reference numerals: 1-Ag / AgCl wire, 2-silver wire, 3-borosilicate nanotube, 4-metal platinum film on the outer wall of the nanotube, 5-copper wire, 6-metal platinum layer on the inner wall of the nanotube, 7-photoelectric active material, 8-working electrode circuit, 9-counter electrode circuit, 10-reference electrode circuit. DETAILED DESCRIPTION
[0025] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. Specific details are set forth in the following description to facilitate a full understanding of the present application, but the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific implementation disclosed below.
[0026] Example 1: Preparation of three-electrode integrated photoelectrochemical microelectrode like Figure 1 As shown, the microelectrode preparation method of the present invention comprises the following steps: Step 1: The cleaned borosilicate capillary is drawn into a nanotube electrode by a laser drawing apparatus.
[0027] Step 2: Inject 10 μL of 9.1% APTES in C2H5OH solution into the nanotube and react at room temperature for 10 min. After the reaction, drain the solution by centrifugation and dry it in a vacuum oven at 60°C for 30 min. Then, inject 10 μL of PEDOT:PSS in CH3OH solution into the nanotube electrode and react in the dark at room temperature for 30 min. Centrifuge the solution out of the nanotube electrode and inject a mixed solution of 25 mM H2PtCl6 and EG. React at 120°C for 1 h to obtain a platinum layer on the inner wall of the nanotube electrode.
[0028] Step 3. Take Cu2O as an example to introduce the electroplating method for preparing photoelectric active materials: a layer of platinum film is sputtered on the outer wall of the nanotube electrode by magnetron sputtering and then placed in a box furnace for annealing. Then 41.01 mg CH3COONa and 181.65 mg Cu(CH3COO)2 are mixed into 50 mL of electroplating solution. The annealed nanotube electrode is immersed in the electroplating solution, a voltage of -0.2 V is applied, and the Cu2O photoelectric material is synthesized by electroplating for 20 s.
[0029] Step 4: Place a silver wire with a diameter of 0.8 mm in a NaClO solution and let it stand for 30 min, then wash it with ultrapure water, and wrap the CA solution on the top of the Ag / AgCl wire. The part not in contact with the cellulose acetate film is insulated, and a part of the silver wire is retained.
[0030] Step 5: Use copper wire to connect the photoelectrically active material on the platinum film on the outer wall of the nanotube electrode as the working electrode, use silver wire to connect the platinum layer on the inner wall of the nanotube as the counter electrode, and finally extend the reference electrode Ag / AgCl wire into the nanotube to assemble a three-electrode integrated photoelectrochemical microelectrode.
[0031] like Figure 2As shown, the integrated electrode of the present invention is composed of seven parts, namely, Ag / AgCl wire (1), silver wire (2), borosilicate nanotube (3), nanotube outer wall metal platinum film (4), copper wire (5), nanotube inner wall metal platinum layer (6), and photoelectric active material (7); one end of the Ag / AgCl wire (1) axially extends into the borosilicate nanotube (3), and the silver wire part outside the borosilicate nanotube serves as an electrode pin and is connected to a reference electrode loop (10); one end of the silver wire (2) axially extends into the borosilicate nanotube (3) and contacts the nanotube inner wall metal platinum layer (6), and the other end is connected to a counter electrode loop (9); one end of the copper wire (5) is wound around the nanotube outer wall metal platinum film (4) and connected to the photoelectric active material (7) electroplated on the nanotube outer wall metal platinum film (4), and the other end is connected to a working electrode loop (8), thereby obtaining a three-electrode integrated photoelectrochemical microelectrode.
[0032] like Figure 3 As shown, three electrodes are integrated into one borosilicate nanotube electrode.
[0033] Example 2: CV test of three-electrode integrated photoelectrochemical microelectrode Inject 6 μL of PBS solution into the microelectrode to ensure that the solution is connected at the tip of the nanotube electrode and there are no bubbles. Fix the assembled three-electrode integrated microelectrode with a clamp, where the copper wire is connected to the working electrode loop, the silver wire is connected to the counter electrode loop, and the Ag / AgCl wire is connected to the reference electrode loop. Place the tip of the microelectrode in a mixed solution of 5 mM potassium ferrocyanide (K6Fe(CN)6) and 5 mM potassium ferrocyanide (K4Fe(CN)6) for CV testing. Figure 4 As shown, Figure 4 a commercial electrode CV diagram for comparison, Figure 4 b and 4c show that the prepared Ag / AgCl wire as a reference electrode and the platinum layer inside the nanotube as a counter electrode can work normally. Figure 4 d shows that the three-electrode integrated photoelectrochemical microelectrode can work normally, further proving that it is feasible to integrate the three electrodes into a micro-nanostructure electrode device.
[0034] Example 3: Photoelectric test of three-electrode integrated photoelectrochemical microelectrode The circuit connection method is the same as above and will not be repeated here. The tip of the three-electrode integrated microelectrode is placed in PBS (pH=7.4) solution, and the photoelectric test is performed under the conditions of an excitation light source wavelength of 480 nm and a bias voltage of 0 V. Figure 5As shown, the Cu2O photoelectric active material as the working electrode, the platinum layer on the inner wall of the nanotube as the counter electrode, and the Ag / AgCl wire as the reference electrode can all work normally and participate in the photoelectrochemical process, indicating that the three-electrode integrated photoelectrochemical microelectrode can perform normal photoelectric testing.
[0035] The above are only a few embodiments of the present invention. The technical means disclosed in the scheme of the present invention are not limited to the technical means disclosed in the above-mentioned implementation mode, but also include technical schemes composed of any combination of the above technical features. Any modifications, equivalent substitutions made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A three-electrode integrated photoelectrochemical microelectrode, characterized in that: The microelectrode consists of seven parts, namely, Ag / AgCl wire, silver wire, borosilicate nanotube, metal platinum film on the outer wall of the nanotube, copper wire, metal platinum layer on the inner wall of the nanotube, and photoelectric active material; one end of the Ag / AgCl wire axially extends into the borosilicate nanotube, the silver wire part outside the borosilicate nanotube is used as an electrode pin and connected to a reference electrode loop; one end of the silver wire axially extends into the borosilicate nanotube and contacts the metal platinum layer on the inner wall of the nanotube, and the other end is connected to a counter electrode loop; one end of the copper wire is wound around the metal platinum film on the outer wall of the nanotube and connected to the photoelectric active material electroplated on the metal platinum film on the outer wall of the nanotube, and the other end is connected to a working electrode loop, so as to obtain a three-electrode integrated photoelectrochemical microelectrode.
2. A method for preparing a three-electrode integrated photoelectrochemical microelectrode, characterized in that: The following steps are involved: Step 1: Preparation of nanotube electrodes: The cleaned borosilicate capillary is drawn into a nanotube electrode by a laser drawing apparatus; Step 2: Prepare the platinum layer on the inner wall of the nanotube: A 3-aminopropyltriethoxysilane solution and a poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) solution are sequentially injected into the nanotube electrode and maintained for a period of time, then the solution is discharged from the nanotube electrode, and then a mixed solution of chloroplatinic acid and ethylene glycol is injected and maintained at a certain temperature for a period of time to obtain a platinum layer on the inner wall of the nanotube electrode; Step 3: Preparation of photoelectrically active materials: A layer of platinum film is sputtered on the outer wall of the nanotube electrode by magnetron sputtering, and then the nanotube electrode is placed in a box furnace for annealing. Then, anhydrous copper acetate and anhydrous sodium acetate are mixed by vigorous stirring, and the annealed nanotube electrode is immersed in the mixed solution for electroplating to synthesize Cu2O photoelectric material; Step 4: Preparation of Ag / AgCl wire: A silver wire with a diameter of 0.08 mm was placed in a sodium hypochlorite solution for 30 minutes and then washed with ultrapure water. A cellulose acetate solution was wrapped on the top of the Ag / AgCl wire. The cellulose acetate membrane formed prevented the reference Ag / AgCl wire from directly contacting the metal platinum layer on the inner wall of the nanotube, preventing short circuit caused by direct contact, while maintaining normal reference function; the part not in contact with the cellulose acetate membrane was insulated, and a part of the silver wire was retained for connecting the circuit; Step 5: Assemble the three-electrode integrated photoelectrochemical nanotube electrode: Copper wire is used to connect the Cu2O photoelectric active material on the platinum film on the outer wall of the nanotube electrode, and silver wire is used to connect the platinum layer on the inner wall of the nanotube. Finally, the treated Ag / AgCl wire is extended into the nanotube to form a three-electrode integrated photoelectrochemical microelectrode.
3. The preparation method according to claim 2, characterized in that In step 1, the borosilicate capillary is immersed in a mixed solution of concentrated sulfuric acid: 30% hydrogen peroxide = 3:1 for 1 h, washed with ultrapure water and dried in a vacuum environment at 80°C.
4. The preparation method according to claim 2, characterized in that: In step 1, the nanotube electrode is drawn by a laser drawing apparatus, and the specific parameters used are set as HEAT=380, FIL=1, VEL=10, DEL=145, and PULL=180.
5. The preparation method according to claim 2, characterized in that: In step 2, 10 μL of 9.1% 3-aminopropyltriethoxysilane ethanol solution was injected into the nanotube electrode, reacted at room temperature for 10 min, then the solution was removed by centrifugation and vacuum dried at 60°C for 30 min, then 10 μL of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) methanol solution was injected into the nanotube electrode, reacted at room temperature in the dark for 30 min, then the solution was removed by centrifugation and vacuum dried at 110°C for 30 min, then 10 μL of a mixed solution of 25 mM chloroplatinic acid and ethylene glycol was injected into the nanotube electrode, reacted at 120°C for 1 h, and after the reaction was completed, the remaining solution was removed from the nanotube electrode by centrifugation to obtain a platinum layer, and finally placed in a box furnace for annealing.
6. The preparation method according to claim 5, characterized in that: In step 2, poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) and methanol are prepared at a volume ratio of 1:1 to form a methanol solution of poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid).
7. The preparation method according to claim 5, characterized in that In step 2, the centrifugation rate was 11800 rpm.
8. The preparation method according to claim 2, characterized in that In step 3, a platinum target is used in the magnetron sputtering process, the sputtering current is 100 mA, and the time is 300 s; and the annealing is performed in a box furnace at 80°C for 1 h.
9. The preparation method according to claim 2, characterized in that: In step 3, the electroplating solution was prepared by dissolving 41.01 mg of anhydrous sodium acetate and 181.65 mg of anhydrous copper acetate in 50 mL of ultrapure water and stirring vigorously for 15 min. The voltage applied during the electroplating process was -0.2 V and the time was 20 s.
10. The preparation method according to claim 2, characterized in that: In step 4, the cellulose acetate solution is prepared by dissolving 1500 mg of cellulose acetate in 3 mL of acetic acid.