Electrode preparation method based on armchair graphene and osmium electron, electrochemical sensor

Abstract

The application relates to an armchair graphene and osmium electron-based electrode preparation method, in which a synthesized armchair graphene solution and a synthesized osmium electron mediator solution are sequentially added dropwise on the surface of a screen-printed carbon electrode, the screen-printed carbon electrode is soaked in an enzyme solution, and after drying, an enzyme electrode for detecting a glucose oxidase electrochemical sensor is prepared. The application also provides an electrochemical sensor, in which the enzyme electrode prepared by the armchair graphene and osmium electron-based electrode preparation method is used as a detection electrode of a glucose oxidase sensor. The prepared armchair graphene nanobelt and osmium electron mediator form an interconnection network, the synthesized armchair graphene nanobelt is less than 5 carbon atom widths, the band gap is narrow, and the armchair graphene nanobelt has excellent conductivity; the electrochemical sensor has a fast electron transfer speed, high current response sensitivity, a slow current decay speed, and good stability.

Description

Technical Field

[0001] This invention relates to the field of electrochemistry, specifically to an electrode preparation method based on armchair graphene and osmium electrons, and an electrochemical sensor. Background Technology

[0002] Glucose is an important carbohydrate in plants and animals, serving as an energy source for living cells and an intermediate product of metabolism. However, excessively high blood sugar can lead to diabetes, which in turn can induce various diseases such as cardiovascular disease, hypertension, and neurological disorders, endangering human health. Furthermore, the incidence of diabetes is relatively high in my country, making rapid measurement of glucose levels in human blood crucial for the clinical diagnosis and treatment of diabetes.

[0003] With the development of electrochemical sensor technology, glucose sensors have become an important research direction in biochemical analysis and clinical testing due to their advantages such as good stability and simple operation. For example, immobilizing glucose oxidase on a biocompatible electrode surface can lead to a rapid electron transfer reaction. Biosensors made using direct electron transfer properties do not require the addition of electron transfer mediators to the analytical solution for electrochemical determination of substrate molecules.

[0004] However, direct contact between glucose oxidase and the bare electrode surface usually causes changes in the structure and function of the protein and causes it to lose its biological activity, thus inhibiting electron transfer of the protein (glucose oxidase) on the electrode. Moreover, the active site of the protein is embedded in a double helix structure and cannot approach the electrode surface, making it difficult to achieve direct electron transfer between the protein and the electrode.

[0005] The above problems are worth solving. Summary of the Invention

[0006] To overcome the shortcomings of existing technologies, this invention provides an electrode preparation method and an electrochemical sensor based on armchair graphene and osmium electrons.

[0007] The technical solution of this invention is as follows:

[0008] Based on the electrode preparation method of armchair graphene and osmium electrons, the synthesized armchair graphene solution and the synthesized osmium electron mediator solution are sequentially dropped onto the surface of screen-printed carbon electrode. The screen-printed carbon electrode is then immersed in enzyme solution and dried to prepare an enzyme electrode for detecting glucose oxidase electrochemical sensor.

[0009] According to the present invention described above, before adding the armchair graphene solution and osmium electron mediator solution, the screen-printed carbon electrode is treated as follows:

[0010] Step A: Ultrasonically clean the screen-printed carbon electrode with sodium hydroxide solution;

[0011] Step B: Ultrasonically clean the screen-printed carbon electrode with a 75% alcohol solution;

[0012] Step C: Soak in deionized water for ultrasonic cleaning and then dry.

[0013] Furthermore, in step A, the concentration of the sodium hydroxide solution is 1 mol / L, and the ultrasonic cleaning time is no less than 30 minutes.

[0014] Furthermore, in step B, the ultrasonic cleaning time with 75% alcohol solution shall not be less than 3 minutes.

[0015] Furthermore, in step C, the ultrasonic cleaning time in deionized water is 1 minute; and the screen-printed carbon electrode is placed in a constant temperature oven at 50°C for drying.

[0016] According to the present invention described above, the specific steps for adding the armchair graphene solution are as follows: using a pipette to draw up the armchair graphene solution and drop it onto the surface of the screen-printed carbon electrode, and then placing it in a constant temperature oven to dry.

[0017] According to the present invention based on the above scheme, the specific steps for adding the osmium electron mediator solution are as follows: using a pipette to draw up the osmium electron mediator solution and drop it onto the surface of the screen-printed carbon electrode modified with armchair graphene, and then placing it in a constant temperature oven to dry.

[0018] According to the present invention described above, the specific steps for screen-printed carbon electrodes soaking in enzyme solution include:

[0019] Step 7: Immerse the screen-printed carbon electrode in enzyme solution at 4℃ for no less than 12 hours;

[0020] Step 8: Rinse with phosphate buffer solution, then rinse with distilled water;

[0021] Step 9: After drying at a constant temperature, store at 4°C.

[0022] According to the present invention described above, after the screen-printed carbon electrode is soaked in an enzyme solution and dried, the method further includes the step of: forming a TPU outer film on the surface of the screen-printed carbon electrode.

[0023] Further, the specific steps for fabricating a TPU outer film on the surface of a screen-printed carbon electrode are as follows: TPU solution is drop-coated onto the surface of the screen-printed carbon electrode and then placed in a constant temperature oven to dry; this process is repeated three times to generate a TPU outer film on the surface of the screen-printed carbon electrode.

[0024] The present invention also provides an electrochemical sensor, characterized in that the enzyme electrode prepared by the above-mentioned electrode preparation method based on armchair graphene and osmium electrons is used as the detection electrode of the glucose oxidase sensor.

[0025] According to the above-described solution, the beneficial effects of this invention are as follows:

[0026] 1) The prepared armchair graphene nanoribbons and osmium electron mediators constitute an interconnection network. Graphene retains a few layered features, which establishes a three-dimensional transport network and a high specific surface area hybrid structure for direct electron transfer. Furthermore, the synthesized armchair graphene nanoribbons are less than 5 carbon atoms wide, have a narrow band gap, and exhibit superior conductivity.

[0027] 2) The redox potential difference of the electrochemical sensor is 91mV, and the electron transfer rate is relatively fast; the osmium electron mediator can reduce the redox potential to 0.22V and 1.3V.

[0028] 3) The electrochemical sensor has high current response sensitivity and high accuracy.

[0029] 4) The electrochemical sensor has good stability: after multiple consecutive scans, the deviation of the catalytic oxidation current response is small; after a period of time (about two weeks later), the current value is still 90% of the original value.

[0030] 5) The electrochemical sensor has a fast response speed, with a reaction time of less than 4 seconds. Attached Figure Description

[0031] Figure 1 This is a flowchart of the method for preparing enzyme electrodes in this invention;

[0032] Figure 2 AFM image of an armchair-shaped graphene;

[0033] Figure 3 The CV curve obtained by cyclic voltammetry is shown.

[0034] Figure 4 The current-time characteristic graph of the electrochemical sensor;

[0035] Figure 5 This is a graph showing the decay of the detected current. Detailed Implementation

[0036] To better understand the purpose, technical solution, and technical effects of this invention, the invention will be further explained and described below in conjunction with the accompanying drawings and embodiments. It should be noted that similar reference numerals and letters in the following drawings indicate similar items; therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. It is also stated that the embodiments described below are only for explaining this invention and are not intended to limit this invention.

[0037] like Figure 1As shown, an electrode preparation method based on armchair-type graphene and osmium electrons involves sequentially dropping a synthesized armchair-type graphene solution and a synthesized osmium electron mediator solution onto the surface of a screen-printed carbon electrode, then immersing the screen-printed carbon electrode in an enzyme solution, and finally drying it to prepare an enzyme electrode for detecting glucose oxidase using an electrochemical sensor.

[0038] like Figure 2 As shown, the synthesized armchair-shaped graphene nanoribbons are less than 5 carbon atoms wide, with a narrow band gap, exhibiting almost metallic properties. The maximum length of the graphene nanoribbons is 70 nm, the median length is 15 nm, and the width is 2.5 nm. The narrow band gap of the armchair-shaped graphene nanoribbons, acting as molecular wires, can serve as interconnects in molecular-scale circuits. These molecular wires facilitate rapid electron transfer in the interconnection between glucose oxidase and electrodes, thus demonstrating superior conductivity. Therefore, the armchair-shaped graphene nanoribbons, with their small diameter, large surface area, good conductivity, biocompatibility, and catalytic activity, can improve the electron transfer rate between electroactive materials when used to modify electrodes.

[0039] As can be seen, the armchair-shaped graphene nanoribbons synthesized in this invention can improve the reversibility of redox reactions in biomolecules, acting as molecular conductors, reducing the overpotential caused by redox reactions, and immobilizing bioenzyme molecules. The synthesized osmium electron mediator in this invention can reduce the redox potential to 0.22V and 1.3V, effectively lowering the reaction potential of the glucose sensor and increasing the electron transfer rate. Furthermore, the armchair-shaped graphene nanoribbons and osmium electron mediators on the screen-printed carbon electrode form an interconnected network. The armchair-shaped graphene retains a few layered features, establishing a three-dimensional transport network and a high specific surface area hybrid structure for direct electron transfer.

[0040] In this invention, the synthesis steps of graphene for armchairs include:

[0041] Step 1: Prepare phenylene diiodide;

[0042] When a Grignard reagent is added to a hexabromobenzene solution, followed by the addition of iodine solution, a phenylene diiodide is formed. The chemical reaction is as follows:

[0043]

[0044] Step 2: Introduction of functional groups;

[0045] Adding a 94% boron tribromide solution introduces a hydroxyl functional group, and the chemical reaction is as follows:

[0046]

[0047] Step 3: Use 1,4-phenylenediborate as an intermediate to carry out a coupling reaction;

[0048] First, a palladium catalyst is added, followed by bromobenzene solution and phenylboronic acid solution in sequence. The chemical reaction formula is as follows:

[0049]

[0050] Step 4: Synthesize 2D graphene nanosheets with functional edges

[0051] By adding a Lewis acid / base catalyst and dichloromethane, and reacting at room temperature for 72 hours, 2d graphene nanosheets with functional edges were synthesized. The chemical reaction formula is as follows:

[0052]

[0053] In this invention, the chemical reaction formula for the synthesis of osmium electron mediators is as follows:

[0054]

[0055] Before adding the armchair graphene solution and osmium electron mediator solution, the screen-printed carbon electrode was treated as follows:

[0056] Step A: Ultrasonically clean the screen-printed carbon electrode with sodium hydroxide solution; wherein the concentration of sodium hydroxide solution is 1 mol / L, and the ultrasonic cleaning time is not less than 30 minutes, to remove the crosslinking agent particles and oil stains on the surface of the screen-printed carbon electrode.

[0057] Step B: Ultrasonically clean the screen-printed carbon electrode with a 75% alcohol solution; specifically, the ultrasonic cleaning time with a 75% alcohol solution shall not be less than 3 minutes to remove the insoluble organic matter on the surface of the screen-printed carbon electrode.

[0058] Step C: Soak in deionized water for ultrasonic cleaning and then dry; specifically, the ultrasonic cleaning time in deionized water is 1 minute; and the screen-printed carbon electrode is placed in a constant temperature oven at 50°C for drying.

[0059] After the above pretreatment, the screen-printed carbon electrode is first subjected to the addition of an armchair graphene solution. Specifically, a micropipette is used to apply the armchair graphene solution to the surface of the screen-printed carbon electrode, which is then placed in a constant temperature oven to dry. Next, an osmium electron mediator solution is added. This is done by applying the solution to the surface of the armchair graphene-modified screen-printed carbon electrode using a micropipette, followed by further drying in a constant temperature oven.

[0060] After adding an armchair graphene solution and an osmium electron mediator solution to the surface of a screen-printed carbon electrode, it is then immersed in an enzyme solution. Specific steps include:

[0061] Step 7: Immerse the screen-printed carbon electrode in the enzyme solution at 4°C for at least 12 hours (or overnight);

[0062] Step 8: Rinse with phosphate buffer solution, then rinse with distilled water;

[0063] Step 9: After drying at a constant temperature, store at 4°C.

[0064] Finally, a TPU outer film is made on the dried screen-printed carbon electrode surface to form a protective film. The specific steps are as follows: TPU solution is dripped onto the screen-printed carbon electrode surface and then placed in a constant temperature oven to dry; this process is repeated three times to generate a TPU outer film on the screen-printed carbon electrode surface.

[0065] This invention also provides an electrochemical sensor, wherein the enzyme electrode prepared by the above-described electrode preparation method is used as the detection electrode of a glucose oxidase sensor, and the voltammetric curve (CV characteristic) of the enzyme electrode is used as a reference. Figure 3 And current-time characteristics (IT characteristics) reference Figure 4 .

[0066] The CV curve shows that the redox potential difference is 91 mV. The current-time characteristic graph shows that the electrochemical sensor has high current response sensitivity and fast response speed.

[0067] like Figure 5 As shown in the figure, the horizontal axis represents time (seconds) and the vertical axis represents current (microamps, uA). After preparing a TPU outer film on the enzyme electrode surface of the electrochemical sensor, it exhibits good stability: the catalytic oxidation current response deviation is small after multiple continuous scans; after a period of time (about two weeks later), the current value is still 90% of the original value.

[0068] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0069] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An electrode fabrication method based on graphene and osmium electron mediators for armchairs, characterized in that, The synthesized armchair graphene solution and the synthesized osmium electron mediator solution were sequentially dropped onto the surface of a screen-printed carbon electrode. The screen-printed carbon electrode was then immersed in a glucose enzyme solution and dried to prepare an enzyme electrode for an electrochemical sensor to detect glucose. The process also includes the following steps: creating a TPU outer film on the surface of a screen-printed carbon electrode. Specifically, a TPU solution is drop-coated onto the surface of the screen-printed carbon electrode and then placed in a constant temperature oven to dry. The above drop-coating and drying process is repeated three times to generate a TPU outer film on the surface of the screen-printed carbon electrode. Among them, the armchair graphene is an armchair-shaped graphene nanoribbon with a width of less than 5 carbon atoms. The armchair-shaped graphene nanoribbon acts as a molecular wire on the surface of the screen-printed carbon electrode, realizing the rapid transfer of electrons between glucose oxidase and the screen-printed carbon electrode. It forms an interconnection network with the osmium electron mediator, establishing a three-dimensional transport network and a hybrid structure with a high specific surface area for direct electron transfer. The synthesis steps of the graphene in the armchair include: Step 1: Prepare phenylene diiodide; When a Grignard reagent is added to a hexabromobenzene solution, followed by the addition of iodine solution, a phenylene diiodide is formed. The chemical reaction is as follows: ； Step 2: Introduction of functional groups; Adding a 94% boron tribromide solution introduces a hydroxyl functional group, and the chemical reaction is as follows: ； Step 3: Use 1,4-phenylenediborate as an intermediate to carry out a coupling reaction; First, a palladium catalyst is added, followed by bromobenzene solution and phenylboronic acid solution in sequence. The chemical reaction formula is as follows: ； Step 4: Synthesize 2D graphene nanoribbons with functional edges By adding Lewis acid catalyst and dichloromethane, and reacting at room temperature for 72 hours, 2D graphene nanoribbons with functional edges were synthesized. The chemical reaction formula is as follows: 。 2. The electrode preparation method based on armchair graphene and osmium electron mediator according to claim 1, characterized in that, The chemical reaction formula for the synthesis of osmium electron mediators is as follows: 。 3. The electrode preparation method based on armchair graphene and osmium electron mediator according to claim 1, characterized in that, Before adding the armchair graphene solution and osmium electron mediator solution, the screen-printed carbon electrode was treated as follows: Step A: Ultrasonically clean the screen-printed carbon electrode with sodium hydroxide solution; Step B: Ultrasonically clean the screen-printed carbon electrode with a 75% alcohol solution; Step C: Soak in deionized water for ultrasonic cleaning and then dry.

4. The electrode preparation method based on armchair graphene and osmium electron mediator according to claim 1, characterized in that, The specific steps for adding the graphene solution to the armchair are as follows: A pipette was used to draw up the graphene solution from the armchair and drop it onto the surface of the screen-printed carbon electrode, which was then placed in a constant temperature oven to dry.

5. The electrode preparation method based on armchair graphene and osmium electron mediator according to claim 1, characterized in that, The specific steps for adding the osmium electron mediator solution are as follows: Osmium electron mediator solution was pipetted onto the surface of a screen-printed carbon electrode modified with armchair graphene and then placed in a constant temperature oven to dry.

6. The electrode preparation method based on armchair graphene and osmium electron mediator according to claim 1, characterized in that, The specific steps for immersing screen-printed carbon electrodes in glucose enzyme solution include: Step 1: Immerse the screen-printed carbon electrode in glucose enzyme solution at 4℃ for no less than 12 hours; Step 2: Rinse with phosphate buffer solution, then rinse with distilled water; Step 3: After drying at a constant temperature, store at 4°C.

7. An electrochemical sensor, characterized in that, The enzyme electrode prepared by the electrode preparation method based on armchair graphene and osmium electron mediator as described in any one of claims 1-6 is used as the detection electrode of the glucose sensor.

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