Nano potassium ion selective electrode and preparation method thereof

Abstract

The invention relates to the technical field of nano electrode preparation, in particular to a nano potassium ion selective electrode and a preparation method thereof. The potassium ion selective electrode is developed by vapor deposition of a conductive carbon layer and electrochemical deposition of an ion selective layer Prussian blue (PB) film on the inner wall of a quartz glass tube (the diameter is less than or equal to 500nm), and the prepared electrode has a wide detection range (10 <-5 >-10 <-1 > M K < + >; r2 is equal to 0.9954) and low detection limit (LDD is equal to 3.38 mu M), and the bottleneck that the potassium ion concentration cannot be stably tracked at the nanoscale in the prior art is broken through.

Description

Technical Field

[0001] This invention relates to the field of nanoelectrode fabrication technology, and in particular to a nanopotassium ion selective electrode and its fabrication method. Background Technology

[0002] Traditional glass microelectrode technology uses glass tube electrodes doped with ion carriers (such as valine) to detect specific ions (such as K+) using membrane potential. + Its tip size is typically >1μm, which easily causes membrane damage when puncturing cells, making it unable to penetrate small cells (such as neuronal synapses and stem cells). High-impedance glass limits the types of ion carriers, resulting in low selectivity. Defects and shortcomings: 1. Insufficient material stability, leading to easy membrane failure. 2. Traditional PVC-based membranes are easily peeled off at micro / nano interfaces. 3. Weak selectivity and weak anti-interference ability, unable to meet K-line requirements under background interference. + 4. Detection limits are too high, limited by the small effective surface area of ​​the nanoelectrode and the low density of the ion carrier, with detection limits generally in the mM range. 5. Poor single-cell compatibility and high cell damage rate: Rigid, large-sized electrode puncture easily causes irreversible tearing of the cell membrane, resulting in a cell survival rate of <60% after puncture. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a nano-potassium ion selective electrode and its preparation method. This invention does not use PVC as the base film; instead, it employs a double-layer modification technique—vapor deposition of a carbon layer and electrochemical deposition of a PB film—within a quartz glass tube (diameter ≤ 500 nm) to obtain a more stable electrode. This electrode can meet the requirements for detecting K under background interference. + This meets the specific detection requirements. The detection limit is 3.38 μM, far below the common mM level. During the detection process, no morphological changes occurred in the cells, and the cell membrane integrity was maintained.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] This invention provides a method for preparing a nano-potassium ion-selective electrode, comprising the following steps:

[0006] 1) After arranging quartz nanotubes neatly, carbon deposition is performed to obtain carbon quartz nanoelectrodes;

[0007] The conditions for carbon deposition include: a temperature of 955°C, a time of 25 min, an argon flow rate of 180 mL / min, and a methane flow rate of 300 mL / min.

[0008] 2) Using the carbon quartz nanoelectrode described in step 1) as the working electrode, silver / silver chloride as the reference electrode, and platinum wire as the counter electrode, Prussian blue thin film electrodeposition was performed by cyclic voltammetry to obtain a nano-potassium ion selective electrode.

[0009] The parameters for the cyclic voltammetry electrodeposition are: window range -0.2 to 0.6 V, scan rate 100 mV / s, sampling interval 2 s, and total electrodeposition time 1280 s.

[0010] Preferably, the quartz nanotube in step 1) has the following specifications: total length of 3.5 cm; inner diameter of one end of 0.5 mm and outer diameter of 1 mm; pointed shape of the other end with a size of less than 500 nm; and the electrode as a whole is conical with a half-cone angle of 4°.

[0011] Preferably, the method for preparing the quartz nanotube includes the following steps: drawing a capillary quartz tube to obtain a quartz nanotube;

[0012] The capillary nanotubes have the following specifications: inner diameter of 0.5 mm, outer diameter of 1 mm, and length of 7 cm.

[0013] Preferably, the drawing is performed on a laser needle drawing machine with the following parameters:

[0014] The first line of parameters is: laser power intensity is 850 (no unit), laser electrical width is 4mm, drawing speed is 35mm / s, delay time is 128ms, and tensile strength is 50 (no unit).

[0015] The second set of parameters is as follows: laser power intensity is 670, laser electrical width is 3mm, drawing speed is 45mm / s, delay time is 45ms, and tensile strength is 105.

[0016] Preferably, the number of quartz nanotubes arranged neatly in step 1) is 10-30.

[0017] Preferably, in step 2), the electrodeposition solution used in the cyclic voltammetry method has a ferric chloride concentration of 2.5 mmol / L, a potassium ferrocyanide trihydrate concentration of 2.5 mmol / L, a potassium chloride concentration of 0.1 mol / L, and a 0.1 mol / L hydrochloric acid solution as the solvent.

[0018] Preferably, the heating rate of carbon deposition in step 1) is: from 25°C to 955°C in 90 minutes.

[0019] Preferably, after cyclic voltammetry electrodeposition in step 2), the nano-potassium ion selective electrode is obtained by cleaning and drying.

[0020] Use deionized water for cleaning;

[0021] The drying conditions include a temperature of 20–30°C and a time of 24 hours.

[0022] The present invention also provides a nano-potassium ion selective electrode prepared by the preparation method described in the above technical solution.

[0023] This invention also provides the application of the nano-potassium ion selective electrode described above in the preparation of cancer treatment products targeting ion channels.

[0024] The beneficial effects of this invention are:

[0025] This invention provides a nano-potassium ion-selective electrode, which... + Selecting the characteristic peak potential of nanoelectrodes to influence intracellular K + The concentration change showed a significant response. Using an electrochemical method, this invention successfully achieved stimulation-induced K+ kinase in living cells. + Dynamic real-time tracking. This sensor has a wide detection range (10). -5 Up to 10 -1 MK + ;R 2 =0.9954) and low detection limit (LOD = 3.38 μM).

[0026] The core innovation of this invention lies in the development of a nano-potassium ion-selective electrode. This electrode is achieved through a dual-layer modification technique involving vapor-phase deposition of a conductive carbon layer and electrochemical deposition of an ion-selective PB film within quartz glass (diameter ≤ 500 nm). The prepared electrode exhibits a wide detection range (10... -5 Up to 10 -1 MK + ;R 2 With a low limit of detection (LOD = 3.38 μM) of 0.9954, it overcomes the bottleneck of existing technologies that cannot stably track potassium ion concentration at the nanoscale. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below.

[0028] Figure 1 This is a schematic diagram of the electrode fabrication process;

[0029] Figure 2 TEM image of a pre-deposited Prussian blue quartz nanoelectrode;

[0030] Figure 3 TEM image of an electrodeposited Prussian blue quartz nanoelectrode;

[0031] Figure 4 For electrochemical testing, the left side shows the electrode stability, with the peak current remaining stable after 1-50 cycles in the background. The right side shows the effect of different electrodeposition times on electrode stability (160, 480, 800, 1280, 1600 s), with 1280 s being the optimal value.

[0032] Figure 5For electrochemical testing, the left image shows the response of the nano-potassium ion-selective electrode to different potassium ion concentrations (potassium ion concentration from left to right: 0, 10). -5 Up to 10 -1 M), the right side is the logarithmic relationship between potential change and potassium ion concentration;

[0033] Figure 6 For electrochemical testing, the nano-potassium ion-selective electrode responds to a variety of metal ions. The greater the potential shift, the higher the selectivity, with potassium ions showing a much higher selectivity than other metal ions.

[0034] Figure 7 During the cell invasion process, the cell morphology did not change in the early, middle, and late stages. Detailed Implementation

[0035] This invention provides a method for preparing a nano-potassium ion-selective electrode, comprising the following steps:

[0036] 1) After arranging quartz nanotubes neatly, carbon deposition is performed to obtain carbon quartz nanoelectrodes;

[0037] The conditions for carbon deposition include: a temperature of 955°C, a time of 25 min, an argon flow rate of 180 mL / min, and a methane flow rate of 300 mL / min.

[0038] 2) Using the carbon quartz nanoelectrode described in step 1) as the working electrode, silver / silver chloride as the reference electrode, and platinum wire as the counter electrode, Prussian blue thin film electrodeposition was performed by cyclic voltammetry to obtain a nano-potassium ion selective electrode.

[0039] The parameters for the cyclic voltammetry electrodeposition are: window range -0.2 to 0.6 V, scan rate 100 mV / s, sampling interval 2 s, and total electrodeposition time 1280 s.

[0040] This invention involves arranging quartz nanotubes neatly and then depositing carbon to obtain a carbon quartz nanoelectrode. The carbon deposition conditions include: a temperature of 955℃, a time of 25 min, an argon flow rate of 180 mL / min, and a methane flow rate of 300 mL / min.

[0041] In this invention, the preferred specifications of the quartz nanotube are: a total length of 3.5 cm; an inner diameter of 0.5 mm and an outer diameter of 1 mm at one end; a pointed shape at the other end with a size less than 500 nm; and a cone-shaped electrode with a semi-cone angle of 4°. The preferred method for preparing the quartz nanotube in this invention includes the following steps: drawing a capillary quartz tube to obtain a quartz nanotube; the specifications of the capillary nanotube are: an inner diameter of 0.5 mm, an outer diameter of 1 mm, and a length of 7 cm. In this invention, the drawing is preferably performed on a laser drawing instrument with the following parameters: the first row of parameters is: laser power intensity of 850 ohms, laser electrical width of 4 mm, drawing speed of 35 mm / s, delay time of 128 ms, and tensile strength of 50; the second row of parameters is: laser power intensity of 670 ohms, laser electrical width of 3 mm, drawing speed of 45 mm / s, delay time of 45 ms, and tensile strength of 105. In this invention, the number of quartz nanotubes arranged in a neat pattern is preferably 10-30. In this invention, the preferred heating rate for carbon deposition is 90 minutes from 25°C to 955°C.

[0042] This invention uses the aforementioned carbon quartz nanoelectrode as the working electrode, silver / silver chloride as the reference electrode, and platinum wire as the counter electrode. Prussian blue thin film electrodeposition is performed using cyclic voltammetry to obtain a nano-potassium ion selective electrode. The parameters of the cyclic voltammetry electrodeposition are: window range -0.2 to 0.6 V, scan rate 100 mV / s, sampling interval 2 s, and total electrodeposition time 1280 s.

[0043] In this invention, the preferred concentrations of ferric chloride, potassium ferrocyanide, and potassium chloride in the electrodeposition solution used for cyclic voltammetry electrodeposition are 2.5 mmol / L, 2.5 mmol / L, and 0.1 mol / L, respectively. The preferred solvent is a 0.1 mol / L hydrochloric acid solution. In this invention, after the cyclic voltammetry electrodeposition, the electrode is preferably cleaned and dried to obtain a nano-potassium ion-selective electrode. Deionized water is preferably used for cleaning. In this invention, the drying conditions preferably include a temperature of 20–30°C and a time of 24 hours.

[0044] The present invention also provides a nano-potassium ion selective electrode prepared by the preparation method described in the above technical solution.

[0045] This invention also provides the application of the nano-potassium ion selective electrode described above in the preparation of cancer treatment products targeting ion channels.

[0046] To further illustrate the present invention, the following detailed description is provided in conjunction with embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0047] Example 1

[0048] A method for preparing a nano-potassium ion-selective electrode, comprising the following steps:

[0049] Step A: Solution Preparation

[0050] Preparation of solution a: Prepare a 0.1M hydrochloric acid solution in a laboratory environment. Take 10 mL of ultrapure water, slowly add the required amount of hydrochloric acid, stir until completely dissolved, and transfer to a clean container for sealed storage.

[0051] Preparation of electrodeposition solution: Prepare anhydrous ferric chloride (2.5 mM), potassium ferrocyanide trihydrate (2.5 mM), and potassium chloride (0.1 M) in a laboratory environment. Slowly add the required amounts of anhydrous ferric chloride, potassium ferrocyanide trihydrate, potassium chloride, and hydrochloric acid, stir until completely dissolved, and transfer to a clean container for sealed storage.

[0052] Step B: Quartz Nanotube Preparation

[0053] Capillary quartz tube preparation: Select a capillary quartz tube with an inner diameter of 0.5 mm, an outer diameter of 1.0 mm, and a length of 7 cm as the starting material.

[0054] Using a laser needle drawing device:

[0055] Attach the capillary tube to the stretching component of the laser needle drawing device. Set the parameters of the laser needle drawing device. The first row of parameters is: HEAT (drawing temperature) = 850 (unitless), FIL (laser electrical width) = 4mm, VEL (drawing speed) = 35mm / s, DEL (delay time) = 128ms, PUL (drawing force) = 50 (unitless); the second row of parameters is: HEAT (drawing temperature) = 670 (unitless), FIL (laser electrical width) = 3mm, VEL (drawing speed) = 45mm / s, DEL (delay time) = 45ms, PUL (drawing force) = 105 (unitless).

[0056] Start the needle puller and preheat for 30 minutes. A laser will irradiate the capillary quartz tube. Then, the stretching component of the laser stretcher will apply tension until the program is completed. The specifications of the quartz nanopore are: total length 3.5cm; one end inner diameter 0.5mm, outer diameter 1mm; the other end is a pointed shape with a size less than 500nm. The electrode is conical in shape with a half-cone angle of 4°.

[0057] Step C: Preparation of carbon quartz nanoelectrodes

[0058] Tubular furnace program settings:

[0059] Twenty quartz nanotubes were neatly arranged on a quartz boat. The parameters of the tube furnace were set, and the temperature was increased from 25°C to 955°C in 90 minutes, maintained for 25 minutes, and then the cooling program was started.

[0060] Gas flow meter parameter settings:

[0061] Argon flow rate 180 mL / min, methane flow rate 300 mL / min.

[0062] Start the tube furnace and gas flow meter, arrange the electrodes on the quartz boat, place the quartz boat into the tube furnace, push it to the middle and tighten the valve, introduce argon gas for a period of time and check the airtightness of the device, start the tube furnace program, introduce methane after 90 minutes, turn off the methane after 25 minutes, wait for cooling, remove the carbon quartz nanoelectrode when the temperature drops to about 50°C, turn off the argon gas, turn off the gas flow meter and the tube furnace, the carbon deposition thickness is about 20 nm.

[0063] Step D: Prussian blue thin film electrodeposition:

[0064] Using a carbon quartz nanoelectrode as the working electrode, silver / silver chloride as the reference electrode, and platinum wire as the counter electrode, cyclic voltammetry was employed for electrodeposition. The electrodeposition solution was prepared in step A. Parameter settings included a window range of -0.2 to 0.6 V, a scan rate of 100 mV / s, a sampling interval of 2 s, and a total electrodeposition time of 1280 s. The Prussian blue film electrodeposition thickness was approximately 5 nm.

[0065] Step E: Cleaning and Drying

[0066] The electrode after electrodeposition was cleaned with deionized water and then dried at room temperature for 24 hours to obtain a nano-potassium ion selective electrode.

[0067] Figure 1 This is a simplified flowchart illustrating the fabrication of a potassium ion-selective nanoelectrode. First, a carbon-quartz nanoelectrode is obtained by vapor deposition of a carbon layer into quartz nanopores via methane pyrolysis. Then, a Prussian blue film is electrodeposited onto the carbon-quartz nanoelectrode.

[0068] Figure 2 and Figure 3 Carbon quartz nanoelectrodes without Prussian blue film deposition and carbon quartz nanoelectrodes with Prussian blue film deposition were respectively obtained using a transmission electron microscope (JEOL Ltd., JEM-2100) to obtain transmission electron microscope images (TEM images) of the electrode tips. Figure 2 The image shows a TEM image of a carbon quartz nanoelectrode before Prussian blue film deposition. A distinct nanopore structure can be observed, with a pore size of approximately 500 nm and a tip angle of approximately 4°. Figure 3This is a TEM image of a carbon quartz nanoelectrode after Prussian blue film deposition. Uniformly layered material can be observed within the quartz nanoporous structure. Figure 2 and Figure 3 The comparison demonstrates that Prussian blue can be deposited onto the inner wall of quartz nanopores using chemical deposition.

[0069] Figure 4 Cyclic voltammetry (left) and the relationship between deposition cycle number and peak current retention rate (right) for the stability test of the nano-potassium ion-selective electrode are shown. A three-electrode system was used: the working electrode was the nano-potassium ion-selective electrode, the reference electrode was an Ag / AgCl electrode, and the counter electrode was a platinum wire. The scanning voltage range was -0.2 to 0.6 V, the voltage scan rate was 100 mV / s, and the scan time was 1280 s. The electrical signals were recorded by an electrochemical workstation (Shanghai Chenhua Co., Ltd., CHI660E). The electrode stability of the nano-potassium ion-selective electrode under a 0.1 M Tris-HCl buffer background was tested. A pair of redox peaks originating from Prussian blue were observed near 0.2 V. After 50 cycles, the peak current retention rate of the Prussian blue redox peak was greater than 95%, and the mid-peak potential remained almost unchanged, proving that the nano-potassium ion-selective electrode has good stability. With the increase of the deposition cycle number, the peak current retention initially increased and then tended to stabilize. The stability was good at a deposition time of 1280 s.

[0070] Figure 5 Cyclic voltammetry curves (left) and logarithmic linear fitting curves (right) of the mid-peak potential versus potassium ion concentration gradient response of the nano-potassium ion-selective electrode are shown. A three-electrode system was used: the working electrode was the nano-potassium ion-selective electrode, the reference electrode was an Ag / AgCl electrode, and the counter electrode was a platinum wire. The scanning voltage range was -0.2 to 0.6 V, and the voltage scan rate was 100 mV / s. The electrical signals were recorded using an electrochemical workstation (Shanghai Chenhua Co., Ltd., CHI660E). The nano-potassium ion-selective electrode was tested in the presence of 0, 10, and 10% potassium ion concentration gradients. -5 -10 -1 MK + Cyclic voltammetry curves of 0.1M Tris-HCl solution show that the electrode at 10... - 5 M-10 -1 Within the M concentration range, K + The concentration change exhibits a linear response, when K + As the concentration gradually increases, the redox peak current of Prussian blue remains relatively stable, while the mid-peak potential undergoes a significant positive shift. This response exhibits excellent linear correlation, R0 2 Up to 0.9954.

[0071] Figure 6Cyclic voltammetry curves were used to selectively measure the selectivity of the nano-potassium ion-selective electrode. A three-electrode system was employed: the working electrode was the nano-potassium ion-selective electrode, the reference electrode was an Ag / AgCl electrode, and the counter electrode was a platinum wire. The scanning voltage range was -0.2 to 0.6 V, and the voltage scan rate was 100 mV / s. The electrical signals were recorded using an electrochemical workstation (Shanghai Chenhua Co., Ltd., CHI660E). Cyclic voltammetry curves of the nano-potassium ion-selective electrode were tested in 0.1 M Tris-HCl solutions containing 10 mM potassium ions and common interfering ions. A larger peak potential shift indicated higher selectivity, with potassium ions showing significantly higher selectivity than other metal ions.

[0072] Figure 7 To investigate the cell invasion process, an integrated micromanipulation-microimaging system (40x magnification) was constructed to monitor the penetration of the cell membrane by a nano-potassium ion-selective electrode in real time. Human cervical cancer cells (HeLa) were used as a typical model for the development of the live-cell sensor for validation. Bright-field microscopy confirmed that cell morphology remained unchanged and membrane integrity remained stable during electrode insertion and measurement.

[0073] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing a nano-potassium ion-selective electrode, characterized in that, Includes the following steps: 1) After arranging quartz nanotubes neatly, carbon deposition is performed to obtain carbon quartz nanoelectrodes; The conditions for carbon deposition include: a temperature of 955°C, a time of 25 min, an argon flow rate of 180 mL / min, and a methane flow rate of 300 mL / min. 2) Using the carbon quartz nanoelectrode described in step 1) as the working electrode, silver / silver chloride as the reference electrode, and platinum wire as the counter electrode, Prussian blue thin film was prepared by electrodeposition using cyclic voltammetry to obtain a nano-potassium ion selective electrode. The parameters for the cyclic voltammetry electrodeposition are: window range -0.2 to 0.6 V, scan rate 100 mV / s, sampling interval 2 s, and total electrodeposition time 1280 s.

2. The preparation method according to claim 1, characterized in that, The specifications of the quartz nanotube in step 1) are as follows: the total length is 3.5cm; the inner diameter of one end is 0.5mm and the outer diameter is 1mm; the other end is a pointed shape with a size of less than 500nm; the electrode is a cone shape with a half cone angle of 4° and a tip size of 500nm.

3. The preparation method according to claim 1 or 2, characterized in that, The method for preparing the quartz nanotubes includes the following steps: drawing capillary quartz tubes to obtain quartz nanotubes; The capillary nanotubes have the following specifications: inner diameter of 0.5 mm, outer diameter of 1 mm, and length of 7 cm.

4. The preparation method according to claim 3, characterized in that, The drawing process is performed on a laser needle drawing machine with the following parameters: The first set of parameters is: laser power intensity is 850, laser electrical width is 4mm, drawing speed is 35mm / s, delay time is 128ms, and tensile strength is 50. The second set of parameters is as follows: laser power intensity is 670, laser electrical width is 3mm, drawing speed is 45mm / s, delay time is 45ms, and tensile strength is 105.

5. The preparation method according to claim 1, characterized in that, Step 1) The number of quartz nanotubes arranged neatly is 10-30.

6. The preparation method according to claim 1, characterized in that, In step 2), the solution used for cyclic voltammetry electrodeposition has a concentration of 2.5 mmol / L for ferric chloride, 2.5 mmol / L for potassium ferrocyanide, 0.1 mol / L for potassium chloride, and is a 0.1 mol / L hydrochloric acid solution as the solvent.

7. The preparation method according to claim 1, characterized in that, Step 1) The heating rate for carbon deposition is: 90 min from 25°C to 955°C.

8. The preparation method according to claim 1, characterized in that, Step 2) After cyclic voltammetry electrodeposition, the nano-potassium ion-selective electrode is obtained by cleaning and drying. Use deionized water for cleaning; The drying conditions include a temperature of 20–30°C and a time of 24 hours.

9. A nano-potassium ion selective electrode prepared by the preparation method according to any one of claims 1 to 7.

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