Three-dimensional flexible carbon-based material and preparation method and application thereof

Abstract

The present application is directed to the problem of small specific surface area, low active site density and limited active material loading of the electrode surface of the conventional glassy carbon electrode, and provides a three-dimensional flexible carbon-based material and a preparation method thereof, comprising: weighing SEBS and adding it into a toluene solution to stir into a uniform solution; taking carbon nanotubes, graphene powder, graphite powder, sodium bicarbonate and white sugar and stirring uniformly; taking the toluene solution of SEBS, adding it into the mixed powder, adding toluene solution, stirring until mixed uniformly to obtain carbon slurry; taking the carbon slurry, transferring it into a corresponding mold for shaping, transferring the shaped slurry into anhydrous ethanol for soaking to solidify the carbon slurry; after the solidified carbon slurry material is dried, it is immersed into a hydrochloric acid solution to obtain a three-dimensional carbon-based material with a porous structure. The present application synthesizes a three-dimensional, porous, flexible and conductive carbon-based material, which is applied to a biological sensing electrode or a biological fuel cell to effectively increase the specific surface area and active material attachment sites of the electrode.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biosensor material preparation and application, and particularly relates to a preparation method and application of a three-dimensional flexible carbon-based material. BACKGROUND

[0002] Biosensors can realize accurate detection of biomarkers and are widely used in biomedical, medical care, environmental monitoring and food detection, etc. With the continuous development and innovation of biosensor related technologies such as biotechnology, nanotechnology and catalytic technology, the application field thereof is also more and more extensive.

[0003] Biosensors based on electrochemical technology are one of important sensors, which have the advantages of rapid detection and convenient portability. The biosensors generally complete detection based on a three-electrode bioelectrode. The working electrode of the three-electrode bioelectrode is modified with specific sensitive materials (such as enzymes, antigens, antibodies, nanomaterials, etc.) and can respond to the measured object and convert the signals into electrical signals that can be received and processed, so as to realize detection of biomarkers.

[0004] The selection of biosensor electrode materials is crucial to the performance of the sensor. Traditional glassy carbon electrodes and screen-printed electrodes have small specific surface area, which leads to less active sites or limited loading of active substances, and finally limits the sensitivity, detection limit and other performances of the biosensor. At the same time, the above electrodes are generally hard substrate electrodes, which are not suitable for the increasingly popular wearable applications. Therefore, it is of great significance to develop an electrode material with large specific surface area and flexible characteristics. SUMMARY

[0005] The present application aims to provide a three-dimensional flexible carbon-based material with large specific surface area and a preparation method thereof, and to apply the three-dimensional flexible carbon-based material to a biosensor electrode, so as to effectively improve the detection performance of the sensor.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solution:

[0007] A preparation method of a three-dimensional flexible carbon-based material, comprising the following steps:

[0008] (1) A certain amount of styrene-ethylene-butylene-styrene block copolymer (SEBS) is weighed and added to a toluene solution, and stirred until the SEBS is completely dissolved in the toluene to form a uniform solution;

[0009] (2) A certain amount of carbon nanotubes, graphene powder, graphite powder, sodium bicarbonate and white sugar are weighed and mixed uniformly by stirring;

[0010] (3) take a certain amount of SEBS toluene solution, add the mixed powder obtained in step (2), then add toluene solution, continue to stir until the mixture is uniform, obtain carbon slurry;

[0011] (4) take a certain amount of carbon slurry, according to the required shape, transfer it to the corresponding mold for shaping, then transfer the shaped slurry to anhydrous ethanol for soaking, exchange the toluene in the carbon slurry to anhydrous ethanol through solution exchange, so that the carbon slurry is solidified;

[0012] (5) after the solidified carbon slurry material is dried, it is immersed in a hydrochloric acid solution, the sodium bicarbonate in the material reacts with the hydrochloric acid to generate sodium chloride, carbon dioxide and water; the generated sodium chloride and the white sugar in the material are dissolved in water, and a three-dimensional carbon-based material with a porous structure is obtained.

[0013] Preferably, the stirring conditions of steps (1), (2), (3) are: magnetic stirring at 1500 rpm for not less than 20 minutes.

[0014] Preferably, the soaking in anhydrous ethanol in step (4) is not less than 30 minutes.

[0015] Preferably, the soaking in 1.0M hydrochloric acid in step (5) is not less than 30 minutes.

[0016] A three-dimensional flexible carbon-based material of the present application is prepared by the above method.

[0017] The three-dimensional flexible carbon-based material prepared by the above method is used in the preparation of a biosensor electrode.

[0018] The present application also provides a preparation method of a lactic acid biosensor electrode, comprising the following steps:

[0019] 1) cut the three-dimensional flexible carbon-based material prepared by the method of claim 1 into the required shape for use;

[0020] 2) print a conductor on the surface of an insulating base material;

[0021] 3) bond the cut three-dimensional flexible carbon-based material to one end of the conductor through conductive carbon paste or conductive polymer paste, and solidify it in a temperature environment below 100°C for standby use;

[0022] 4) deposit a layer of gold nanoparticles on the surface of the carbon material electrode prepared in step 3) through electrodeposition technology in a three-electrode system;

[0023] 5) prepare a 0.15M concentration of naphthoquinone solution, and drop coat the naphthoquinone solution on the electrode surface of the electrode in step 4), and let it dry naturally;

[0024] 6) 10 mg / mL lactic acid enzyme modification solution is configured with deionized water, and 10 mg / mL bovine serum albumin (BSA) is added therein, 10 microliters of lactic acid enzyme modification solution is taken and drop-coated on the surface of the electrode, and the electrode is placed at room temperature for a period of time;

[0025] 7) A chitosan solution with a mass percentage of 1% is configured, wherein the solvent is 0.1M acetic acid; 5 microliters of the chitosan solution is taken and drop-coated on the surface of the electrode;

[0026] 8) A glutaraldehyde solution with a mass fraction of 1% is configured, wherein the solvent is deionized water; 5 microliters of the glutaraldehyde solution is taken and drop-coated on the surface of the electrode;

[0027] 9) The modified electrode is placed at a temperature of 4-10°C for a period of time, and is obtained.

[0028] Preferably, the insulating base material in step (2) comprises polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), and insulating ceramic.

[0029] Preferably, the wire material in step (2) is silver paste, silver chloride paste, conductive polymer paste, conductive carbon paste, or a mixture of the above pastes.

[0030] The application also provides a lactic acid biosensor electrode prepared by the above disclosed method.

[0031] The application also provides a preparation method of an enzyme-free glucose biosensor electrode, comprising the following steps:

[0032] 1) The three-dimensional flexible carbon-based material prepared by the method of claim 1 is cut into a desired shape for use;

[0033] 2) A wire is printed on the surface of the insulating base material;

[0034] 3) The cut three-dimensional flexible carbon-based material is bonded to one end of the wire through conductive carbon paste or conductive polymer paste, and is solidified in a temperature environment below 100°C for standby use;

[0035] 4) A layer of cobalt-copper double hydroxide nanomaterial is deposited on the surface of the carbon material electrode prepared in step 3) through electrodeposition technology in a three-electrode system;

[0036] 5) The deposited electrode is washed with deionized water, and is obtained.

[0037] Preferably, the insulating base material in step (2) comprises polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), and insulating ceramic.

[0038] Preferably, the wire material in step (2) is silver paste, silver chloride paste, conductive polymer paste, conductive carbon paste or a mixture of the above pastes.

[0039] The application also provides an enzyme-free glucose biosensor electrode prepared by the above disclosed method.

[0040] The technical scheme of the application has the following beneficial effects:

[0041] 1. The application synthesizes a three-dimensional, porous, flexible and conductive carbon-based material to solve the problems of small specific surface area, few active sites and limited loading capacity of active substances on the electrode surface of traditional glassy carbon electrodes and screen-printed electrodes, and the carbon-based material can be applied to biosensor electrodes or biological fuel cells to effectively increase the specific surface area and active material adhesion sites of the electrodes, thereby improving the performance of the devices.

[0042] 2. The carbon-based material synthesis method of the application is simple and low in cost, and the porosity, flexibility and conductivity of the material can be controlled by appropriately changing the material ratio or introducing other materials.

[0043] 3. The carbon-based material prepared by the application has good stability and can stably exist in acidic or alkaline solutions. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 The flexible three-dimensional carbon-based material is prepared by the method of the application.

[0045] Figure 2 The SEM image of the three-dimensional flexible carbon-based material prepared in Example 1 of the application.

[0046] Figure 3 The cyclic voltammetry test curve for detecting 10 mM lactic acid.

[0047] Figure 4 The cyclic voltammetry test curves for detecting 0 mM, 1 mM, 3 mM and 6 mM glucose, respectively. DETAILED DESCRIPTION

[0048] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application, but do not constitute a limitation on the protection scope of the application.

[0049] The raw materials used in the three-dimensional flexible carbon-based material of the application include carbon nanotubes, graphene, graphite powder, sodium bicarbonate, white granulated sugar, styrene-ethylene-butylene-styrene block copolymer (SEBS), toluene, anhydrous ethanol and dilute hydrochloric acid. In addition, carbon black, carbon powder and other carbon materials can also be added according to specific functional requirements, and metal or metal oxide and other functional materials can also be added.

[0050] Embodiment 1

[0051] A preparation method of a three-dimensional flexible carbon-based material, specifically comprising the following steps:

[0052] 1) 2.0g of SEBS is weighed and added to 5mL of toluene solution, and is magnetically stirred at 1500rpm for 30 minutes, and the SEBS is completely dissolved in the toluene to form a uniform solution;

[0053] 2) 0.3g of carbon nanotubes, 0.03g of graphene powder, 0.03g of graphite powder, 5.5g of sodium bicarbonate and 1.0g of white sugar are weighed, and the powders are magnetically stirred at 1500rpm for 20 minutes to make the powders uniformly mixed;

[0054] 3) 1.2g of the toluene solution of SEBS is weighed and added to the mixed powders obtained in step 2), and then 1.5mL of toluene solution is immediately added, and the mixture is magnetically stirred at 1500rpm for 30 minutes to make the SEBS solution, the toluene solution and the powders uniformly mixed, thereby obtaining a carbon slurry;

[0055] 4) A certain amount of the carbon slurry is taken and filled into a mold with a size of 2cm*1cm*2mm (length* width*depth) to shape, and then the shaped slurry is immediately transferred to anhydrous ethanol for soaking for 30 minutes, and during the soaking process, the toluene in the carbon slurry can be exchanged into anhydrous ethanol through solution exchange, so that the carbon slurry is solidified;

[0056] 5) After the solidified carbon slurry material is naturally dried, it is soaked in 1.0M hydrochloric acid for 30 minutes, and during the soaking process, the sodium bicarbonate in the material reacts with the hydrochloric acid to generate sodium chloride, carbon dioxide and water; the generated sodium chloride and the white sugar in the material are dissolved into water, thereby obtaining a flexible three-dimensional carbon-based material with a porous structure.

[0057] As shown in Figure 1 , the carbon-based material prepared in the embodiment of the present application has good flexibility and can be bent at any angle.

[0058] As shown in Figure 2 , the synthesized three-dimensional flexible carbon-based material is characterized by using an electron microscope (SEM): under a magnification of 400 times, it can be observed that the surface of the carbon-based material prepared in the present application is distributed with holes of different sizes, which proves that the material is indeed a porous material.

[0059] The present application also provides a preparation method of a lactic acid biosensor electrode, specifically comprising the following steps:

[0060] 1) The obtained three-dimensional flexible carbon-based material is cut into a size of 0.5cm*0.3cm (length* width) for standby;

[0061] 2) Print the conductive wire (the shape of the conductive wire is not limited) on the surface of the insulating base material (such as polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), insulating ceramic, etc.) by screen printing or other methods (the printing method is not limited). The conductive wire material can be silver paste, silver chloride paste, conductive polymer paste, conductive carbon paste, or metal paste, or a mixture of the above pastes;

[0062] 3) Bond the cut three-dimensional flexible carbon-based material to one end of the conductive wire through conductive carbon paste or conductive polymer paste, and solidify it in a temperature environment below 100°C for standby;

[0063] 4) In the three-electrode system, deposit a layer of gold nanoparticles on the surface of the prepared carbon material electrode by electrodeposition technology, wherein the counter electrode is a 1cm*1cm platinum mesh electrode, the reference electrode is a silver / silver chloride electrode, the deposition electrolyte is a 10mM chloroauric acid solution, the deposition voltage is -0.2V, and the deposition time is 100 seconds;

[0064] 5) Prepare a 0.15M naphthoquinone solution, wherein the solvent is a mixture of acetone and ethanol with a mass ratio of 1:9; take 10 microliters of the naphthoquinone solution and drop it on the electrode surface of the electrode described in step 4), and let it dry naturally;

[0065] 6) Prepare a 10mg / mL lactic acid enzyme modification solution with deionized water, and add 10mg / mL bovine serum albumin (BSA) to it. After mixing evenly, take 10 microliters of the lactic acid enzyme modification solution and drop it on the electrode surface, and place it at room temperature for 3 hours;

[0066] 7) Prepare a 1% chitosan solution, wherein the solvent is 0.1M acetic acid; take 5 microliters of the chitosan solution and drop it on the electrode surface;

[0067] 8) Prepare a 1% glutaraldehyde solution, wherein the solvent is deionized water; take 5 microliters of the glutaraldehyde solution and drop it on the electrode surface;

[0068] 9) Place the modified electrode at a temperature of 4-10°C for 12 hours for standby.

[0069] Lactic acid detection

[0070] Use the prepared lactic acid bioelectrode as the working electrode, a 1cm*1cm platinum mesh electrode as the counter electrode, a silver / silver chloride electrode as the reference electrode, and a 0.1M phosphate buffer solution as the test solution to detect lactic acid. Figure 3The figure shows the cyclic voltammetric curve for detecting 10 mM lactic acid. The dashed line represents the data obtained in phosphate buffer without lactic acid, and the solid line represents the curve obtained in phosphate buffer containing 10 mM lactic acid. It can be observed that at a voltage of approximately 0.04 V, a significant oxidation peak is observed in the phosphate buffer containing lactic acid, which is produced by the catalytic oxidation of lactic acid, proving that the prepared electrode can be used for lactic acid detection.

[0071] Example 2

[0072] The preparation method of a three-dimensional flexible carbon-based material is the same as in Example 1.

[0073] This invention also provides a method for preparing an enzyme-free glucose biosensing electrode, specifically including the following steps:

[0074] 1) Cut the obtained three-dimensional flexible carbon-based material into 0.5cm*0.3cm (length*width) pieces for later use;

[0075] 2) Print wires (wire shape is not limited) on the surface of insulating substrate material (such as polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), insulating ceramics, etc.) by means of screen printing or other methods (printing method is not limited). The wire material can be silver paste, silver chloride paste, conductive polymer paste, conductive carbon paste or metal paste or a mixture of the above pastes.

[0076] 3) The cut three-dimensional flexible carbon-based material is bonded to one end of the wire using conductive carbon paste or conductive polymer paste, and cured in an environment below 100°C for later use.

[0077] 4) On the surface of the prepared carbon material electrode, a layer of cobalt-copper double hydroxide (CoCu-DH) nanomaterial was deposited by electrodeposition in a three-electrode system. The counter electrode was a 1cm*1cm platinum mesh electrode, and the reference electrode was a silver / silver chloride electrode. The deposition electrolyte was a mixed aqueous solution of 6mM cobalt nitrate and 3mM copper nitrate. The deposition method was cyclic voltammetry (CV), with a voltage range of -1.2V to 0.3V, a scan rate of 5mV / s, and 5 scan cycles.

[0078] 5) Clean the electrode with deposited CoCu-DH nanomaterials with deionized water and store it at 4-10℃ for later use;

[0079] glucose test

[0080] The prepared enzyme-free glucose electrode was used as the working electrode, a 1cm*1cm platinum mesh electrode was used as the counter electrode, a silver / silver chloride electrode was used as the reference electrode, and a 0.1M sodium hydroxide solution was used as the test solution for glucose detection. Figure 4 The figure shows the cyclic voltammetric curves for detecting 0 mM, 1 mM, 3 mM, and 6 mM lactic acid, respectively. A significant oxidation peak can be observed at approximately 0.5 V. Furthermore, within the range of 0.3 V–0.7 V, the oxidation current value of the cyclic voltammetric curve increases with increasing glucose concentration. This is a result of the catalytic oxidation of glucose, demonstrating that the prepared electrode can be used to detect different concentrations of glucose.

[0081] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. The application of a three-dimensional flexible carbon-based material in the fabrication of biosensing electrodes, wherein the three-dimensional flexible carbon-based material is prepared by the following method, comprising: (1) Weigh a certain amount of styrene-ethylene-butene-styrene block copolymer (SEBS), add it to toluene solution, and stir until SEBS is completely dissolved in toluene to form a homogeneous solution; (2) Weigh a certain amount of carbon nanotubes, graphene powder, graphite powder, sodium bicarbonate and white sugar, and stir the powders until they are evenly mixed. (3) Weigh a certain amount of SEBS toluene solution, add it to the mixed powder obtained in step (2), then add toluene solution, and continue stirring until the mixture is uniform to obtain carbon slurry; (4) Take a certain amount of carbon slurry, transfer it to the corresponding mold according to the required shape, and then transfer the slurry to anhydrous ethanol for soaking. Through solution exchange, the toluene in the carbon slurry is exchanged to the anhydrous ethanol, thereby solidifying the carbon slurry. (5) After the solidified carbon slurry material is dried, it is immersed in hydrochloric acid solution. The sodium bicarbonate in the material will react with hydrochloric acid to generate sodium chloride, carbon dioxide and water. The generated sodium chloride and the white sugar in the material will dissolve in the water to obtain a three-dimensional carbon-based material with a porous structure.

2. The application of the three-dimensional flexible carbon-based material as described in claim 1 in the fabrication of biosensing electrodes, characterized in that: The stirring conditions for steps (1), (2), and (3) are as follows: magnetic stirring at 1500 rpm for no less than 20 minutes; soaking in anhydrous ethanol for no less than 30 minutes in step (4); and soaking in 1.0M hydrochloric acid for no less than 30 minutes in step (5).

3. A method for preparing a lactic acid biosensing electrode, characterized in that, Includes the following steps: 1) Cut the three-dimensional flexible carbon-based material into the required shape for later use; 2) Print wires on the surface of the insulating substrate material; 3) The cut three-dimensional flexible carbon-based material is bonded to one end of the wire using conductive carbon paste or conductive polymer paste, and cured in an environment below 100°C for later use. 4) On the surface of the carbon material electrode prepared in step 3), a layer of gold nanoparticles is deposited by electrodeposition in a three-electrode system; 5) Prepare a 0.15M naphthoquinone solution and drop it onto the electrode surface of the electrode described in step 4), then allow it to air dry naturally; 6) Prepare a 10 mg / mL lactase modification solution with deionized water, add 10 mg / mL bovine serum albumin (BSA) to it, mix well, and then take 10 μL of the lactase modification solution and drop it onto the electrode surface. Let it stand at room temperature for a period of time. 7) Prepare a 1% (w / w) chitosan solution, using 0.1M acetic acid as the solvent; drop 5 μL of the chitosan solution onto the electrode surface; 8) Prepare a 1% glutaraldehyde solution using deionized water as the solvent; apply 5 μL of the glutaraldehyde solution to the electrode surface. 9) Place the modified electrode at 4-10℃ for a period of time to obtain the product; The three-dimensional flexible carbon-based material is prepared by the following method, including: A. Weigh a certain amount of styrene-ethylene-butene-styrene block copolymer (SEBS), add it to a toluene solution, and stir until the SEBS is completely dissolved in the toluene to form a homogeneous solution; B. Weigh out a certain amount of carbon nanotubes, graphene powder, graphite powder, sodium bicarbonate, and white sugar, and stir the powders until they are evenly mixed. C. Weigh a certain amount of SEBS toluene solution, add it to the mixed powder obtained in step (2), then add toluene solution, and continue stirring until the mixture is uniform to obtain carbon slurry; D. Take a certain amount of carbon slurry, transfer it to the corresponding mold according to the required shape, and then transfer the slurry to anhydrous ethanol for immersion. Through solution exchange, the toluene in the carbon slurry is exchanged into the anhydrous ethanol, thereby solidifying the carbon slurry. E. After the cured carbon slurry material is dried, it is immersed in hydrochloric acid solution. The sodium bicarbonate in the material will react with hydrochloric acid to produce sodium chloride, carbon dioxide and water. The generated sodium chloride and the white sugar in the material will dissolve in the water to obtain a three-dimensional carbon-based material with a porous structure.

4. The method for preparing a lactic acid biosensing electrode as described in claim 3, characterized in that: The stirring conditions for steps A, B, and C are as follows: magnetic stirring at 1500 rpm for at least 20 minutes; soaking in anhydrous ethanol for at least 30 minutes in step D; and soaking in 1.0M hydrochloric acid for at least 30 minutes in step E.

5. The method for preparing a lactic acid biosensing electrode as described in claim 3, characterized in that: The insulating substrate material mentioned in step (2) includes polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), and insulating ceramics; the conductor material is silver paste, silver chloride paste, conductive polymer paste, conductive carbon paste, or a mixture of the above pastes.

6. A lactic acid biosensing electrode, characterized in that: It is prepared by the method according to any one of claims 3-5.

7. A method for preparing a glucose biosensing electrode, characterized in that, Includes the following steps: 1) Cut the three-dimensional flexible carbon-based material into the required shape for later use; 2) Print wires on the surface of the insulating substrate material; 3) The cut three-dimensional flexible carbon-based material is bonded to one end of the wire using conductive carbon paste or conductive polymer paste, and cured in an environment below 100 degrees Celsius for later use. 4) On the surface of the carbon material electrode prepared in step 3), a layer of cobalt copper double hydroxide nanomaterial is deposited by electrodeposition technology in a three-electrode system; 5) The electrode with deposited nanomaterials was rinsed with deionized water to obtain the final product; The three-dimensional flexible carbon-based material is prepared by the following method, including: A. Weigh a certain amount of styrene-ethylene-butene-styrene block copolymer (SEBS), add it to a toluene solution, and stir until the SEBS is completely dissolved in the toluene to form a homogeneous solution; B. Weigh out a certain amount of carbon nanotubes, graphene powder, graphite powder, sodium bicarbonate, and white sugar, and stir the powders until they are evenly mixed. C. Weigh a certain amount of SEBS toluene solution, add it to the mixed powder obtained in step (2), then add toluene solution, and continue stirring until the mixture is uniform to obtain carbon slurry; D. Take a certain amount of carbon slurry, transfer it to the corresponding mold according to the required shape, and then transfer the slurry to anhydrous ethanol for immersion. Through solution exchange, the toluene in the carbon slurry is exchanged into the anhydrous ethanol, thereby solidifying the carbon slurry. E. After the cured carbon slurry material is dried, it is immersed in hydrochloric acid solution. The sodium bicarbonate in the material will react with hydrochloric acid to produce sodium chloride, carbon dioxide and water. The generated sodium chloride and the white sugar in the material will dissolve in the water to obtain a three-dimensional carbon-based material with a porous structure.

8. The method for preparing a glucose biosensing electrode as described in claim 7, characterized in that: The insulating substrate material mentioned in step (2) includes polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), and insulating ceramics; the conductor material is silver paste, silver chloride paste, conductive polymer paste, conductive carbon paste, or a mixture of the above pastes.

9. A glucose biosensing electrode, characterized in that: The method described in any one of claims 7-8 is used to prepare the product.

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