A glucose oxidase sensor based on modified multi-walled carbon nanotube modification
By modifying glassy carbon electrodes with multi-walled carbon nanotubes, the problems of detection stability and lifespan of glucose oxidase sensors were solved, achieving high-sensitivity and long-life glucose detection and improving the overall performance of the sensor.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHENZHEN COFOE BIOTECHNOLOGY CO LTD
- Filing Date
- 2023-10-24
- Publication Date
- 2026-07-24
AI Technical Summary
Existing glucose oxidase sensors have shortcomings in detection stability and reusability, resulting in low detection sensitivity and poor storage stability.
A glassy carbon electrode was modified with modified multi-walled carbon nanotubes. This was achieved by mixing multi-walled carbon nanotubes with nano-bentonite and then oxidizing them. Maleic anhydride and ethylene glycol dimethyl acrylate were added and refluxed, combined with Nafion solution covering, which improved the electrode's specific surface area, conductivity, biocompatibility, and catalytic activity.
It improves the sensitivity and stability of glucose detection in the sensor, extends its service life, maintains the activity of glucose oxidase, and enhances storage stability and effectiveness for multiple uses.
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Figure CN117517421B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of glucose oxidase sensor technology, and in particular to a glucose oxidase sensor based on modified multi-walled carbon nanotubes. Background Technology
[0002] Glucose is an important carbohydrate in plants and animals. It is the energy source for plant and animal cells and an intermediate product of metabolism. However, the concentration of blood sugar in the human body cannot be too high. Excessive blood sugar can cause diabetes, which can induce a variety of complications, such as cardiovascular disease, hypertension, and neurological disorders, causing damage to human health. It can be seen that the harm of excessive blood sugar is quite great. At present, the incidence of diabetes is relatively high in my country. Therefore, the rapid measurement of blood sugar is of great significance for the clinical diagnosis and treatment of diabetes.
[0003] In existing technologies, there are generally three methods for detecting glucose concentration using glucose oxidase electrodes. The first method detects glucose concentration by measuring the electrons transferred during the redox reaction of hydrogen peroxide, a product of the glucose oxidase enzymatic reaction, on the electrode surface. The second method detects glucose concentration by using electron mediators such as potassium ferricyanide and ferrocene to transfer electrons transferred during the enzymatic reaction to the electrode surface. The third method detects blood glucose concentration by using materials such as metal nanoparticles, graphene, and carbon nanotubes to achieve direct electron transfer between the enzyme and the electrode.
[0004] Glucose oxidase is characterized by high specificity, high efficiency, and mildness, and has wide applications in medicine, food, and bio-industry.
[0005] However, glucose sensors prepared by existing technologies have issues with glucose detection stability, often exhibiting problems such as glucose oxidase deficiency, short reusability, and poor storage stability. Consequently, the glucose oxidase sensors produced have low detection sensitivity and can only be reused a limited number of times. Therefore, further improvements to existing technologies are necessary. Summary of the Invention
[0006] The purpose of this invention is to provide a glucose oxidase sensor based on modified multi-walled carbon nanotubes to overcome the shortcomings of the prior art.
[0007] The technical solution adopted in this invention is as follows:
[0008] A glucose oxidase sensor based on modified multi-walled carbon nanotubes includes the following steps:
[0009] (1) Preparation of modified multi-walled carbon nanotubes:
[0010] Multi-walled carbon nanotubes were mixed with nano-bentonite, and glycerol was used as a grinding aid. The mixture was ground for 1-2 hours and then dried to obtain the mixed nanomaterial.
[0011] The mixed nanomaterials are oxidized to obtain oxidized nanomaterials;
[0012] Oxidized nanomaterials are added to an organic solvent and dispersed evenly to obtain a dispersion.
[0013] A 2.6% maleic anhydride solution and ethylene glycol dimethyl acrylate were added to the dispersion, and the mixture was refluxed at 80-85℃ for 2 hours. The mixture was then filtered, washed, and dried to obtain modified multi-walled carbon nanotubes.
[0014] (2) Polish the glassy carbon electrode, then clean it until it is neutral, and then dry it.
[0015] (3) Add the modified multi-walled carbon nanotubes prepared in step (1) to the PBS solution, and after uniform dispersion, obtain the modified multi-walled carbon nanotube dispersion.
[0016] (4) Add glucose oxidase to the modified multi-walled carbon nanotube dispersion and stir until homogeneous to obtain glucose oxidase solution.
[0017] (5) Insert the treated glassy carbon electrode into glucose oxidase solution and immerse it for 40-50 minutes. Then remove it and dry it.
[0018] (6) Cover the dried glassy carbon electrode surface with Nafion solution, dry it, and store it at 4°C.
[0019] As a further technical solution: the mass ratio of the multi-walled carbon nanotubes to nano-bentonite in step (1) is 10:1-1.8;
[0020] The grinding aid is used at 30% of the mass of the multi-walled carbon nanotubes;
[0021] The grinding speed is 1200 r / min.
[0022] As a further technical solution: the method for preparing the oxidized nanomaterials in step (1) is as follows:
[0023] First, add 3-5g of the mixed nanomaterials to 100mL of sulfuric acid solution and stir for 20min at room temperature. Then add 1-2g of potassium permanganate, adjust the temperature to 60℃, keep it warm and stir for 1 hour, then filter, wash until neutral, and dry to obtain the oxidized nanomaterials.
[0024] As a further technical solution: the mixing ratio of the oxidized nanomaterial and the organic solvent in step (1) is 15-18g:100mL;
[0025] The mixing ratio of the dispersion, the 2.6% maleic anhydride solution, and the ethylene glycol dimethyl acrylate is 100 mL: 3-4 g: 4-6 g.
[0026] As a further technical solution: the organic solvent is toluene.
[0027] As a further technical solution: the polishing of the glassy carbon electrode in step (2) is to polish the surface of the glassy carbon electrode with 0.15μm and 0.05μm alumina suspensions in sequence, and then soak and clean it with pure water and anhydrous ethanol for 20 minutes respectively, and dry it in a 40℃ drying oven for 2 hours.
[0028] As a further technical solution: in the modified multi-walled carbon nanotube dispersion described in step (3), the mixing ratio of modified multi-walled carbon nanotubes and PBS solution is 10-15g:100mL.
[0029] As a further technical solution: the mixing ratio of glucose oxidase and modified multi-walled carbon nanotube dispersion in step (4) is 1-1.6g:100mL.
[0030] As a further technical solution: In step (5), the drying is carried out by infrared drying, and the drying time is 30 minutes.
[0031] As a further technical solution: the mass fraction of the Nafion solution in step (6) is 5%.
[0032] The modified multi-walled carbon nanotubes prepared by this invention have higher specific surface area and chemical stability. Furthermore, due to their predominantly carbon atom structure, they possess excellent electrical conductivity, providing a better channel for electron transfer. Moreover, because this invention modifies conventional multi-walled carbon nanotubes, they exhibit better biocompatibility, adsorption, and catalytic activity. In particular, the significantly improved adsorption performance allows for higher adsorption and immobilization of glucose oxidase, while excellent biocompatibility maintains high glucose oxidase activity, thereby enhancing the detection stability of the sensor.
[0033] Beneficial effects:
[0034] This invention provides a glucose oxidase sensor based on modified multi-walled carbon nanotubes, which has the following advantages:
[0035] The present invention modifies the electrode by introducing modified multi-walled carbon nanotubes, resulting in a sensor that not only has high glucose detection sensitivity but also excellent stability.
[0036] The high stability of the product of this invention is reflected in two aspects: first, storage stability, which can still maintain high glucose oxidase activity after long-term storage; and second, the high glucose oxidase activity can still be maintained after multiple cycles of use, thereby greatly improving its utilization rate, extending its service life, and making it more economical. Attached Figure Description
[0037] Figure 1 This is a bar chart showing the enzyme activity retention rate after the sensor has been stored. Detailed Implementation
[0038] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0039] Example 1
[0040] A glucose oxidase sensor based on modified multi-walled carbon nanotubes includes the following steps:
[0041] (1) Preparation of modified multi-walled carbon nanotubes:
[0042] Multi-walled carbon nanotubes were mixed with nano-bentonite, and glycerol was used as a grinding aid. The mixture was ground for 1 hour and then dried to obtain the mixed nanomaterial.
[0043] The mixed nanomaterials are oxidized to obtain oxidized nanomaterials;
[0044] Oxidized nanomaterials were added to toluene and dispersed evenly to obtain a dispersion.
[0045] A 2.6% (w / w) solution of maleic anhydride and ethylene glycol dimethyl acrylate were added to the dispersion, and the mixture was refluxed at 80°C for 2 hours. The mixture was then filtered, washed, and dried to obtain modified multi-walled carbon nanotubes. The method for preparing the oxidized nanomaterials is as follows:
[0046] First, add 3g of the mixed nanomaterial to 100mL of sulfuric acid solution and stir for 20min at room temperature. Then add 1g of potassium permanganate, adjust the temperature to 60℃, keep it warm and stir for 1 hour, then filter, wash until neutral, and dry to obtain the oxidized nanomaterial. The mixing ratio of the oxidized nanomaterial and toluene is 15g:100mL.
[0047] The dispersion, a 2.6% maleic anhydride solution, and ethylene glycol dimethyl acrylate were mixed in a ratio of 100 mL: 3 g: 4 g. The mass ratio of multi-walled carbon nanotubes to nano-bentonite was 10:1.
[0048] The grinding aid is used at 30% of the mass of the multi-walled carbon nanotubes;
[0049] The grinding speed is 1200 r / min.
[0050] (2) Polish the surface of the glassy carbon electrode, then clean it until it is neutral, and then dry it. Polishing the glassy carbon electrode involves polishing the surface of the glassy carbon electrode with 0.15μm and 0.05μm alumina suspensions in sequence, then immersing and cleaning it in pure water and anhydrous ethanol for 20 minutes respectively, and then drying it in a 40℃ drying oven for 2 hours.
[0051] (3) Add the modified multi-walled carbon nanotubes prepared in step (1) to the PBS solution and disperse them evenly to obtain a modified multi-walled carbon nanotube dispersion. The mixing ratio of modified multi-walled carbon nanotubes and PBS solution in the modified multi-walled carbon nanotube dispersion is 10g:100mL.
[0052] (4) Add glucose oxidase to the modified multi-walled carbon nanotube dispersion and stir evenly to obtain glucose oxidase solution; the mixing ratio of glucose oxidase and modified multi-walled carbon nanotube dispersion is 1g:100mL.
[0053] (5) Insert the treated glassy carbon electrode into glucose oxidase solution and immerse it for 40 minutes. Then take it out and dry it. The drying is done by infrared drying for 30 minutes.
[0054] (6) Cover the surface of the dried glassy carbon electrode with a 5% Nafion solution, dry it, and store it at 4°C.
[0055] Example 2
[0056] A glucose oxidase sensor based on modified multi-walled carbon nanotubes includes the following steps:
[0057] (1) Preparation of modified multi-walled carbon nanotubes:
[0058] Multi-walled carbon nanotubes were mixed with nano-bentonite, and glycerol was used as a grinding aid. The mixture was ground for 1.5 hours and then dried to obtain the mixed nanomaterial.
[0059] The mixed nanomaterials are oxidized to obtain oxidized nanomaterials;
[0060] Oxidized nanomaterials were added to toluene and dispersed evenly to obtain a dispersion.
[0061] A 2.6% (w / w) solution of maleic anhydride and ethylene glycol dimethyl acrylate were added to the dispersion, and the mixture was refluxed at 82°C for 2 hours. The mixture was then filtered, washed, and dried to obtain modified multi-walled carbon nanotubes. The method for preparing the oxidized nanomaterials is as follows:
[0062] First, 3.5g of the mixed nanomaterials were added to 100mL of sulfuric acid solution and stirred at room temperature for 20min. Then, 1.2g of potassium permanganate was added, the temperature was adjusted to 60℃, and the mixture was stirred for 1 hour. After that, the mixture was filtered, washed until neutral, and dried to obtain the oxidized nanomaterials. The mixing ratio of the oxidized nanomaterials and toluene was 16g:100mL.
[0063] The dispersion, a 2.6% maleic anhydride solution, and ethylene glycol dimethyl acrylate were mixed in a ratio of 100 mL: 3.5 g: 4.2 g. The mass ratio of multi-walled carbon nanotubes to nano-bentonite was 10:1.2.
[0064] The grinding aid is used at 30% of the mass of the multi-walled carbon nanotubes;
[0065] The grinding speed is 1200 r / min.
[0066] (2) Polish the surface of the glassy carbon electrode, then clean it until it is neutral, and then dry it. Polishing the glassy carbon electrode involves polishing the surface of the glassy carbon electrode with 0.15μm and 0.05μm alumina suspensions in sequence, then immersing and cleaning it in pure water and anhydrous ethanol for 20 minutes respectively, and then drying it in a 40℃ drying oven for 2 hours.
[0067] (3) Add the modified multi-walled carbon nanotubes prepared in step (1) to the PBS solution and disperse them evenly to obtain a modified multi-walled carbon nanotube dispersion. The mixing ratio of modified multi-walled carbon nanotubes and PBS solution in the modified multi-walled carbon nanotube dispersion is 12g:100mL.
[0068] (4) Add glucose oxidase to the modified multi-walled carbon nanotube dispersion and stir evenly to obtain glucose oxidase solution; the mixing ratio of glucose oxidase and modified multi-walled carbon nanotube dispersion is 1.2g:100mL.
[0069] (5) Insert the treated glassy carbon electrode into glucose oxidase solution and immerse it for 45 minutes. Then take it out and dry it. The drying is done by infrared drying for 30 minutes.
[0070] (6) Cover the surface of the dried glassy carbon electrode with a 5% Nafion solution, dry it, and store it at 4°C.
[0071] Example 3
[0072] A glucose oxidase sensor based on modified multi-walled carbon nanotubes includes the following steps:
[0073] (1) Preparation of modified multi-walled carbon nanotubes:
[0074] Multi-walled carbon nanotubes were mixed with nano-bentonite, and glycerol was used as a grinding aid. The mixture was ground for 1.6 hours and then dried to obtain the mixed nanomaterial.
[0075] The mixed nanomaterials are oxidized to obtain oxidized nanomaterials;
[0076] Oxidized nanomaterials were added to toluene and dispersed evenly to obtain a dispersion.
[0077] A 2.6% (w / w) solution of maleic anhydride and ethylene glycol dimethyl acrylate were added to the dispersion, and the mixture was refluxed at 83°C for 2 hours. The mixture was then filtered, washed, and dried to obtain modified multi-walled carbon nanotubes. The method for preparing the oxidized nanomaterials is as follows:
[0078] First, add 4g of the mixed nanomaterial to 100mL of sulfuric acid solution and stir for 20min at room temperature. Then add 1.5g of potassium permanganate, adjust the temperature to 60℃, keep it warm and stir for 1 hour, then filter, wash until neutral, and dry to obtain the oxidized nanomaterial. The mixing ratio of the oxidized nanomaterial and toluene is 16g:100mL.
[0079] The dispersion, a 2.6% maleic anhydride solution, and ethylene glycol dimethyl acrylate were mixed in a ratio of 100 mL: 3.5 g: 5 g. The mass ratio of multi-walled carbon nanotubes to nano-bentonite was 10:1.5.
[0080] The grinding aid is used at 30% of the mass of the multi-walled carbon nanotubes;
[0081] The grinding speed is 1200 r / min.
[0082] (2) Polish the surface of the glassy carbon electrode, then clean it until it is neutral, and then dry it. Polishing the glassy carbon electrode involves polishing the surface of the glassy carbon electrode with 0.15μm and 0.05μm alumina suspensions in sequence, then immersing and cleaning it in pure water and anhydrous ethanol for 20 minutes respectively, and then drying it in a 40℃ drying oven for 2 hours.
[0083] (3) Add the modified multi-walled carbon nanotubes prepared in step (1) to the PBS solution and disperse them evenly to obtain a modified multi-walled carbon nanotube dispersion. The mixing ratio of modified multi-walled carbon nanotubes and PBS solution in the modified multi-walled carbon nanotube dispersion is 13g:100mL.
[0084] (4) Add glucose oxidase to the modified multi-walled carbon nanotube dispersion and stir evenly to obtain glucose oxidase solution; the mixing ratio of glucose oxidase and modified multi-walled carbon nanotube dispersion is 1.3g:100mL.
[0085] (5) Insert the treated glassy carbon electrode into glucose oxidase solution and immerse it for 45 minutes. Then take it out and dry it. The drying is done by infrared drying for 30 minutes.
[0086] (6) Cover the dried glassy carbon electrode surface with a 5% Nafion solution, dry it, and store it at 4°C.
[0087] Example 4
[0088] A glucose oxidase sensor based on modified multi-walled carbon nanotubes includes the following steps:
[0089] (1) Preparation of modified multi-walled carbon nanotubes:
[0090] Multi-walled carbon nanotubes were mixed with nano-bentonite, and glycerol was used as a grinding aid. The mixture was ground for 1.6 hours and then dried to obtain the mixed nanomaterial.
[0091] The mixed nanomaterials are oxidized to obtain oxidized nanomaterials;
[0092] Oxidized nanomaterials were added to toluene and dispersed evenly to obtain a dispersion.
[0093] A 2.6% (w / w) solution of maleic anhydride and ethylene glycol dimethyl acrylate were added to the dispersion, and the mixture was refluxed at 84°C for 2 hours. The mixture was then filtered, washed, and dried to obtain modified multi-walled carbon nanotubes. The method for preparing the oxidized nanomaterials is as follows:
[0094] First, 4.5g of the mixed nanomaterials were added to 100mL of sulfuric acid solution and stirred at room temperature for 20min. Then, 1.8g of potassium permanganate was added, the temperature was adjusted to 60℃, and the mixture was stirred for 1 hour. After that, the mixture was filtered, washed until neutral, and dried to obtain the oxidized nanomaterials. The mixing ratio of the oxidized nanomaterials and toluene was 16g:100mL.
[0095] The dispersion, a 2.6% maleic anhydride solution, and ethylene glycol dimethyl acrylate were mixed in a ratio of 100 mL: 3.8 g: 4.2 g. The mass ratio of multi-walled carbon nanotubes to nano-bentonite was 10:1.5.
[0096] The grinding aid is used at 30% of the mass of the multi-walled carbon nanotubes;
[0097] The grinding speed is 1200 r / min.
[0098] (2) Polish the surface of the glassy carbon electrode, then clean it until it is neutral, and then dry it. Polishing the glassy carbon electrode involves polishing the surface of the glassy carbon electrode with 0.15μm and 0.05μm alumina suspensions in sequence, then immersing and cleaning it in pure water and anhydrous ethanol for 20 minutes respectively, and then drying it in a 40℃ drying oven for 2 hours.
[0099] (3) Add the modified multi-walled carbon nanotubes prepared in step (1) to the PBS solution and disperse them evenly to obtain a modified multi-walled carbon nanotube dispersion. The mixing ratio of modified multi-walled carbon nanotubes and PBS solution in the modified multi-walled carbon nanotube dispersion is 12g:100mL.
[0100] (4) Add glucose oxidase to the modified multi-walled carbon nanotube dispersion and stir evenly to obtain glucose oxidase solution; the mixing ratio of glucose oxidase and modified multi-walled carbon nanotube dispersion is 1.5g:100mL.
[0101] (5) Insert the treated glassy carbon electrode into glucose oxidase solution and immerse it for 45 minutes. Then take it out and dry it. The drying is done by infrared drying for 30 minutes.
[0102] (6) Cover the surface of the dried glassy carbon electrode with a 5% Nafion solution, dry it, and store it at 4°C.
[0103] Example 5
[0104] A glucose oxidase sensor based on modified multi-walled carbon nanotubes includes the following steps:
[0105] (1) Preparation of modified multi-walled carbon nanotubes:
[0106] Multi-walled carbon nanotubes were mixed with nano-bentonite, and glycerol was used as a grinding aid. The mixture was ground for 2 hours and then dried to obtain the mixed nanomaterial.
[0107] The mixed nanomaterials are oxidized to obtain oxidized nanomaterials;
[0108] Oxidized nanomaterials were added to toluene and dispersed evenly to obtain a dispersion.
[0109] A 2.6% (w / w) solution of maleic anhydride and ethylene glycol dimethyl acrylate were added to the dispersion, and the mixture was refluxed at 85°C for 2 hours. The mixture was then filtered, washed, and dried to obtain modified multi-walled carbon nanotubes. The method for preparing the oxidized nanomaterials is as follows:
[0110] First, add 5g of the mixed nanomaterial to 100mL of sulfuric acid solution and stir for 20min at room temperature. Then add 2g of potassium permanganate, adjust the temperature to 60℃, keep it warm and stir for 1 hour, then filter, wash until neutral, and dry to obtain the oxidized nanomaterial. The mixing ratio of the oxidized nanomaterial and toluene is 18g:100mL.
[0111] The dispersion, a 2.6% maleic anhydride solution, and ethylene glycol dimethyl acrylate were mixed in a ratio of 100 mL: 4 g: 6 g. The mass ratio of multi-walled carbon nanotubes to nano-bentonite was 10:1.8.
[0112] The grinding aid is used at 30% of the mass of the multi-walled carbon nanotubes;
[0113] The grinding speed is 1200 r / min.
[0114] (2) Polish the surface of the glassy carbon electrode, then clean it until it is neutral, and then dry it. Polishing the glassy carbon electrode involves polishing the surface of the glassy carbon electrode with 0.15μm and 0.05μm alumina suspensions in sequence, then immersing and cleaning it in pure water and anhydrous ethanol for 20 minutes respectively, and then drying it in a 40℃ drying oven for 2 hours.
[0115] (3) Add the modified multi-walled carbon nanotubes prepared in step (1) to the PBS solution and disperse them evenly to obtain a modified multi-walled carbon nanotube dispersion. The mixing ratio of modified multi-walled carbon nanotubes and PBS solution in the modified multi-walled carbon nanotube dispersion is 15g:100mL.
[0116] (4) Add glucose oxidase to the modified multi-walled carbon nanotube dispersion and stir evenly to obtain glucose oxidase solution; the mixing ratio of glucose oxidase and modified multi-walled carbon nanotube dispersion is 1.6g:100mL.
[0117] (5) Insert the treated glassy carbon electrode into glucose oxidase solution and immerse it for 50 minutes. Then take it out and dry it. The drying is done by infrared drying for 30 minutes.
[0118] (6) Cover the surface of the dried glassy carbon electrode with a 5% Nafion solution, dry it, and store it at 4°C.
[0119] Comparative Example 1:
[0120] Based on Example 1, maleic anhydride solution was not added during the preparation of modified multi-walled carbon nanotubes in step (1), while the remaining steps were the same as those in Example 1.
[0121] Comparative Example 2:
[0122] Based on Example 1, the modified multi-walled carbon nanotubes in step (1) are not modified by adding ethylene glycol dimethyl acrylate, while the remaining steps are the same as those in Example 1.
[0123] Table 1 shows the range of glucose solution concentrations under linear detection conditions at an operating voltage of 0.15V, a temperature of 25℃, and a 0.2mol / L PBS buffer.
[0124] Table 1
[0125] Example 1 0.02-25.00 Example 2 0.02-25.00 Example 3 0.02-25.00 Example 4 0.02-25.00 Example 5 0.02-25.00 Comparative Example 1 0.35-20.00 Comparative Example 2 0.50-20.00
[0126] As can be seen from Table 1, the sensor of the present invention exhibits a wide range of good linear relationships (R2 = 0.999) for the catalytic oxidation of glucose solution.
[0127] For the enzyme activity detection of the examples and comparative examples, U0 was recorded. After 15 days of storage, enzyme activity was detected again, and U1 was recorded. The retention rate W compared to the initial value was calculated. The glucose solution concentration was 1.0 mmol / mL.
[0128] W = (U1 / U0) × 100%;
[0129] Table 2
[0130] Example 1 91.35 Example 2 92.08 Example 3 92.75 Example 4 91.24 Example 5 90.05 Comparative Example 1 83.14 Comparative Example 2 80.07
[0131] As can be seen from Table 2, the sensor prepared by the present invention has superior storage stability.
[0132] For the enzyme activity detection of the example and comparative sensors, U2 was recorded. After 100 consecutive detection cycles, enzyme activity was detected again, and U3 was recorded. The retention rate W compared to the initial value was calculated. The glucose solution concentration was 1.0 mmol / mL.
[0133] W = (U3 / U2) × 100%
[0134] Table 3
[0135] Example 1 75.2 Example 2 76.3 Example 3 76.2 Example 4 75.4 Example 5 74.9 Comparative Example 1 58.6 Comparative Example 2 52.3
[0136] As can be seen from Table 3, the sensor prepared by this invention can still maintain high enzyme activity after multiple tests.
[0137] Figure 1 The bar chart shows the enzyme activity retention rate after 15 days of storage for the comparative and example sensors.
[0138] The above description is only a preferred embodiment of the present invention, but the present invention is not limited to the scope of implementation shown. Any changes made in accordance with the concept of the present invention, or equivalent embodiments modified to have equivalent changes, shall be within the protection scope of the present invention as long as they do not exceed the spirit covered by the specification.
Claims
1. A glucose oxidase sensor based on modified multi-walled carbon nanotubes, characterized in that: Includes the following steps: (1) Preparation of modified multi-walled carbon nanotubes: Multi-walled carbon nanotubes were mixed with nano-bentonite, and glycerol was used as a grinding aid. The mixture was ground for 1-2 hours and then dried to obtain the mixed nanomaterial. The mixed nanomaterials are oxidized to obtain oxidized nanomaterials; Oxidized nanomaterials are added to an organic solvent and dispersed evenly to obtain a dispersion. A 2.6% maleic anhydride solution and ethylene glycol dimethyl acrylate were added to the dispersion, and the mixture was refluxed at 80-85℃ for 2 hours. The mixture was then filtered, washed, and dried to obtain modified multi-walled carbon nanotubes. (2) Polish the glassy carbon electrode, then clean it until it is neutral, and then dry it. (3) Add the modified multi-walled carbon nanotubes prepared in step (1) to the PBS solution, and after uniform dispersion, obtain the modified multi-walled carbon nanotube dispersion. (4) Add glucose oxidase to the modified multi-walled carbon nanotube dispersion and stir until homogeneous to obtain glucose oxidase solution. (5) Insert the treated glassy carbon electrode into glucose oxidase solution and immerse it for 40-50 minutes. Then remove it and dry it. (6) Cover the dried glassy carbon electrode surface with Nafion solution, dry it, and store it at 4°C.
2. The glucose oxidase sensor based on modified multi-walled carbon nanotubes according to claim 1, characterized in that: The mass ratio of multi-walled carbon nanotubes to nano-bentonite in step (1) is 10:1-1.8; The grinding aid is used at 30% of the mass of the multi-walled carbon nanotubes; The grinding speed is 1200 r / min.
3. The glucose oxidase sensor based on modified multi-walled carbon nanotubes according to claim 1, characterized in that: The method for preparing the oxidation-treated nanomaterials in step (1) is as follows: First, add 3-5g of the mixed nanomaterials to 100mL of sulfuric acid solution and stir for 20min at room temperature. Then add 1-2g of potassium permanganate, adjust the temperature to 60℃, keep it warm and stir for 1 hour, then filter, wash until neutral, and dry to obtain the oxidized nanomaterials.
4. The glucose oxidase sensor based on modified multi-walled carbon nanotubes according to claim 1, characterized in that: The mixing ratio of the oxidized nanomaterial and the organic solvent in step (1) is 15-18g:100mL; The mixing ratio of the dispersion, the 2.6% maleic anhydride solution, and the ethylene glycol dimethyl acrylate is 100 mL: 3-4 g: 4-6 g.
5. A glucose oxidase sensor based on modified multi-walled carbon nanotubes according to claim 4, characterized in that: The organic solvent is toluene.
6. The glucose oxidase sensor based on modified multi-walled carbon nanotubes according to claim 1, characterized in that: The polishing of the glassy carbon electrode in step (2) involves polishing the surface of the glassy carbon electrode with 0.15μm and 0.05μm alumina suspensions in sequence, then immersing and cleaning it in pure water and anhydrous ethanol for 20 minutes respectively, and then drying it in a 40℃ drying oven for 2 hours.
7. The glucose oxidase sensor based on modified multi-walled carbon nanotubes according to claim 1, characterized in that: In step (3), the modified multi-walled carbon nanotube dispersion has a mixing ratio of 10-15g:100mL for the modified multi-walled carbon nanotubes and PBS solution.
8. The glucose oxidase sensor based on modified multi-walled carbon nanotubes according to claim 1, characterized in that: In step (4), the mixing ratio of glucose oxidase and modified multi-walled carbon nanotube dispersion is 1-1.6g:100mL.
9. A glucose oxidase sensor based on modified multi-walled carbon nanotubes according to claim 1, characterized in that: In step (5), the drying process uses infrared drying for 30 minutes.
10. A glucose oxidase sensor based on modified multi-walled carbon nanotubes according to claim 1, characterized in that: The Nafion solution in step (6) has a mass fraction of 5%.
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