A wearable non-enzymatic electrochemical sensor, a preparation method and application thereof in detecting glucose content
By modifying the electrode surface with gold nanoparticle-doped metal-organic frameworks and calcium alginate gel, the electrochemical signal of glucose is used for real-time monitoring, solving the problem of continuous monitoring of glucose oxidase sensors and achieving specific detection and long-term accuracy of glucose.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHANGZHOU UNIV
- Filing Date
- 2024-07-18
- Publication Date
- 2026-04-14
AI Technical Summary
Existing glucose oxidase sensors cannot achieve continuous monitoring, are easily affected by interference and are inaccurate, are difficult to collect sweat, and are affected by contaminants on the skin surface.
The electrode is modified with gold nanoparticle-doped metal-organic framework and calcium alginate gel. Electrochemical monitoring is performed using the glucose self-oxidation signal, and the antibacterial properties of the hydrogel are combined to achieve long-term use.
This technology enables specific detection and long-term monitoring of glucose, reduces the impact of contaminants on the electrode surface, and improves the accuracy and sustainability of monitoring.
Smart Images
Figure CN119044272B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the fields of analytical chemistry and electrochemistry, specifically relating to a wearable non-enzymatic electrochemical sensor, its preparation method, and its application in detecting glucose content. Technical Background
[0002] Glucose (Glu) is the primary energy source and metabolic product of living cells; excessive intake can lead to numerous health problems, including diabetes. Glu plays a crucial role in clinical diagnosis and blood glucose management as a biomarker for diabetes. However, current blood glucose monitoring methods primarily analyze blood samples, making continuous blood glucose monitoring difficult. Existing research indicates that the concentration of glucose in the sweat of healthy individuals ranges from 10 to 200 μM. Wearable sensors, due to their flexibility, can well match skin tissue, forming a flexible and stable electrode-tissue interface. This allows for rapid, continuous, and non-invasive capture of health changes, showing broad application prospects in continuous glucose monitoring. Wearable electrochemical sensors can continuously monitor specific molecules in bodily fluids (such as sweat, saliva, tears, and tissue fluid). For Glu monitoring, sweat is often the preferred source.
[0003] Analyzing glucose from sweat is a challenging task. Glucose levels in sweat fluctuate depending on the sweat collection method. Furthermore, contaminants on the skin surface, such as lipids, bacteria, and skincare products, can form an uneven layer of dirt on the electrode surface, affecting glucose concentration measurements. Because various conditions, such as temperature, pH, and ionic strength, significantly influence glucose oxidase activity, continuous monitoring using glucose oxidase-based sensors is not feasible.
[0004] This invention employs gold nanoparticles (AuNPs) as a glucose oxidation mimicry enzyme to oxidize Glu into gluconic acid and H₂O₂, replacing glucose oxidase in wearable glucose sensors. Due to the excellent hydrophilicity of hydrogels, they can effectively reduce hydrophobic interactions between the electrode surface and coexisting contaminants, and are widely used in antifouling and antibacterial interfaces for biosensors and implantable devices. Simultaneously, hydrogels can also conveniently collect the user's sweat without requiring exercise or chemical stimulation to induce sweating. Summary of the Invention
[0005] To address the technical problems existing in the prior art, and to solve the issues of glucose oxidase sensors being unable to achieve continuous monitoring, being easily interfered with and inaccurate, and having difficulty in sweat collection, the present invention aims to design and provide a wearable non-enzymatic electrochemical sensor, its preparation method, and its application in glucose detection. The wearable non-enzymatic electrochemical sensor of the present invention can be fixed to the skin surface, and connected to a smartphone via a small electrochemical workstation to record current-time curves for real-time glucose monitoring.
[0006] This invention utilizes the oxidation signal of glucose itself as an electrochemical signal probe. When sweat from the skin is enriched on the sensor surface by calcium alginate gel, it causes a corresponding change in the glucose current signal. Simultaneously, the sensor designed in this invention possesses certain antibacterial properties, which is beneficial for the long-term use of wearable sensors. Based on the linear correlation between the glucose current signal and concentration, specific detection of glucose is achieved.
[0007] To achieve the above objectives, the present invention adopts the following technical solution:
[0008] On one hand, the present invention provides a wearable non-enzymatic electrochemical sensor, which includes an electrode and a gold nanoparticle-doped metal-organic framework and a calcium alginate gel sequentially modified on the electrode surface.
[0009] The wearable non-enzymatic electrochemical sensor described above has a screen-printed electrode.
[0010] Secondly, the present invention provides a method for preparing a wearable non-enzymatic electrochemical sensor, comprising the following steps:
[0011] (1) Weigh gold nanoparticle solution, 2-methylimidazole and hexadecyltrimethylammonium bromide, mix them, add zinc acetate solution, let them stand after fully reacting, centrifuge, dry to obtain precipitate, calcine in nitrogen atmosphere to obtain gold nanoparticle-doped metal-organic framework, dissolve the gold nanoparticle-doped metal-organic framework in water to obtain gold nanoparticle-doped metal-organic framework dispersion.
[0012] (2) Take the electrode, modify the surface of the electrode with a metal-organic framework doped with gold nanoparticles, and add calcium alginate gel to obtain a wearable non-enzymatic electrochemical sensor.
[0013] The preparation method described above, the preparation method of the gold nanoparticle solution in step (1) is as follows: weigh HAuCl4 solution, heat to boiling under vigorous stirring, add trisodium citrate solution, boil, and cool to room temperature.
[0014] In the preparation method described above, the boiling time is 5 to 15 minutes.
[0015] The volume ratio of the HAuCl4 solution to the trisodium citrate solution is 250:3-4;
[0016] The concentration of the HAuCl4 solution is 0.01-0.1%, and the concentration of the trisodium citrate solution is 0.1-1%.
[0017] In the preparation method described above, the volume-to-mass ratio of the gold nanoparticle solution, 2-methylimidazole, hexadecyltrimethylammonium bromide and zinc acetate solution in step (1) is 20-30 mL: 5-6 g: 1-5 mg: 20-30 mL;
[0018] The concentration of the zinc acetate solution is 5-10 mM, the concentration of 2-methylimidazole is 50-100 mM, and the concentration of hexadecyltrimethylammonium bromide is 5-10 μM.
[0019] The settling time is 1 to 3 hours;
[0020] The drying method is freeze-drying;
[0021] The calcination temperature is 700–1000℃, and the calcination time is 1–4 hours.
[0022] The preparation method described above, in step (2), is as follows: Sodium alginate is weighed and dissolved in potassium hydroxide solution to obtain a mixed solution, and a crosslinking agent is added to obtain calcium alginate gel.
[0023] In the preparation method described above, the crosslinking agent is calcium chloride; calcium chloride is used as the crosslinking agent to form a gel from the solution, which is then rapidly drop-coated onto the electrode surface.
[0024] The mass-to-volume ratio of sodium alginate, potassium hydroxide solution, and crosslinking agent is 1-5 mg: 1 mL: 10 μL.
[0025] The concentration of the potassium hydroxide solution is 2–5 mM.
[0026] Thirdly, the present invention provides the application of the wearable non-enzymatic electrochemical sensor described above in real-time monitoring of glucose content in body fluids.
[0027] The concentration of sodium alginate solution is 2–5 mg / mL. -1 Preferably 2 mg / mL -1 The concentration of the CaCl2 solution is 0.1–0.5 g / mL. -1 Preferably 0.1 g mL -1 The volume ratio of the CaCl2 solution to the sodium alginate solution is 1:10.
[0028] Compared with the prior art, the present invention has the following beneficial effects:
[0029] 1. Calcium alginate gel exhibits good swelling properties, which is beneficial for the rapid accumulation of sweat on the electrode surface.
[0030] 2. AuNPs-doped carbide metal-organic frameworks exhibit good catalytic activity, which is beneficial for the oxidation of Glu to gluconic acid on the electrode surface. Among them, AuNPs provide abundant active sites for the redox reaction of Glu, and the organic components of ZIF-8 are carbonized under high temperature conditions, which improves the conductivity of the material and is conducive to electron transfer.
[0031] 3. The anti-fouling properties of calcium alginate gel help prevent non-specific impurities in sweat from affecting electrochemical signals, thereby enabling long-term monitoring of Glu. Attached Figure Description
[0032] Figure 1 This is a scanning electron microscope image of AuNPs@ZIF-8-C prepared in Example 1;
[0033] Figure 2 This is a scanning electron microscope image of CAgel in Example 1;
[0034] Figure 3 This is a swelling curve of CAgel in Example 1;
[0035] Figure 4 The current-time curves of the wearable non-enzymatic electrochemical sensor prepared in Example 1 in Glu solutions of different concentrations are shown.
[0036] Figure 5 The graph shows the linear relationship between the concentration of Glu and the current density when the wearable non-enzymatic electrochemical sensor prepared in Example 1 detects Glu.
[0037] Figure 6 This is the non-specific response signal of the wearable non-enzymatic electrochemical sensor prepared in Example 1;
[0038] Figure 7 The test results show that the wearable non-enzymatic electrochemical sensor prepared in Example 1 was used to monitor the current density in the sweat on the surface of volunteers in real time.
[0039] Figure 8 The results are from the test of the wearable non-enzymatic electrochemical sensor prepared in Example 1 co-cultured with Escherichia coli and Staphylococcus aureus in glucose solution. Detailed Implementation
[0040] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the present invention is not limited to the following embodiments.
[0041] Example 1:
[0042] A method for preparing a wearable non-enzymatic electrochemical sensor for detecting glucose includes the following steps:
[0043] (1) Heat 250 mL of 0.01% HAuCl4 solution to boiling under vigorous stirring. Add 3.75 mL of 1% trisodium citrate solution to the solution and continue boiling for 10 min. Finally, cool the resulting gold nanoparticle solution (i.e., AuNPs solution) to room temperature.
[0044] (2) Add 20 mL of 6.8 mM zinc acetate solution to a mixed solution containing 20 mL of AuNPs, 5.6 g of 2-methylimidazole, and 2 mg of hexadecyltrimethylammonium bromide prepared in step (1). After the reaction is complete, let it stand for 2 h, centrifuge, freeze dry, and finally calcine the dried product at 900 °C for 4 h in a nitrogen atmosphere. Figure 1 The image shown is a scanning electron microscope image of the synthesized AuNPs@ZIF-8-C. It can be observed that the AuNPs@ZIF-8-C particles have a uniform size distribution, an average particle size of about 100 nm, and are arranged in a plate-like manner.
[0045] (3) Transfer 2 mg of sodium alginate to 1 mL of potassium hydroxide solution (2 mM concentration), add 100 μL of 0.1 g / mL potassium hydroxide solution. -1 Calcium chloride was used to obtain calcium alginate gel.
[0046] (4) Weigh 1 mg of AuNPs@ZIF-8-C obtained in step 2, disperse it in 1 mL of ultrapure water, drop-coat the AuNPs@ZIF-8-C dispersion onto the surface of the screen-printed electrode SPCE and dry it, then rapidly drop-coat calcium alginate gel onto the electrode surface to obtain a wearable non-enzymatic electrochemical sensor. Figure 2 The image shown is a scanning electron microscope (SEM) image of calcium alginate gel. It reveals that the calcium alginate gel possesses a three-dimensional network structure, which is beneficial for the accumulation of sweat on the electrode surface. Figure 3 The figure shows the swelling properties of calcium alginate gel (CAgel) in 0.1M phosphate buffer solution (pH=7.4). It can be seen that calcium alginate gel can swell rapidly within 6 minutes, which is beneficial for continuous monitoring of glucose in sweat.
[0047] Example 2:
[0048] A method for preparing a wearable non-enzymatic electrochemical sensor for detecting glucose includes the following steps:
[0049] (1) Heat 250 mL of 0.05% HAuCl4 solution to boiling under vigorous stirring. Add 3 mL of 1% trisodium citrate solution to the solution and continue boiling for 5 min. Finally, cool the resulting gold nanoparticle solution (i.e., AuNPs solution) to room temperature.
[0050] (2) Add 25 mL of 6.8 mM zinc acetate solution to a mixed solution containing 20 mL of AuNPs, 6 g of 2-methylimidazole and 2 mg of cetyltrimethylammonium bromide prepared in step (1). After the reaction is complete, let it stand for 2 h, centrifuge, freeze dry, and finally calcine the dried product at 700 °C for 4 h in a nitrogen atmosphere.
[0051] (3) Transfer 1 mg of sodium alginate to 1 mL of potassium hydroxide solution (2 mM concentration), add 100 μL of 0.1 g / mL potassium hydroxide solution. -1 Calcium chloride was used to obtain calcium alginate gel.
[0052] (4) Weigh 1 mg of AuNPs@ZIF-8-C obtained in Example 1, disperse it in 1 mL of ultrapure water, drop the AuNPs@ZIF-8-C dispersion onto the surface of the screen-printed electrode SPCE and dry it, then quickly drop calcium alginate gel onto the electrode surface to obtain a wearable non-enzymatic electrochemical sensor.
[0053] Example 3:
[0054] A method for preparing a wearable non-enzymatic electrochemical sensor for detecting glucose includes the following steps:
[0055] (1) Heat 250 mL of 0.1% HAuCl4 solution to boiling under vigorous stirring. Add 4 mL of 0.1% trisodium citrate solution to the solution and continue boiling for 15 min. Finally, cool the resulting gold nanoparticle solution (i.e., AuNPs solution) to room temperature.
[0056] (2) Add 30 mL of 6.8 mM zinc acetate solution to a mixed solution containing 20 mL of AuNPs, 5 g of 2-methylimidazole and 1 mg of cetyltrimethylammonium bromide prepared in step (1), let it stand for 2 h after the reaction is complete, centrifuge, freeze dry, and finally calcine the dried product at 1000 °C for 1 h in a nitrogen atmosphere.
[0057] (3) Transfer 5 mg of sodium alginate to 1 mL of potassium hydroxide solution (2 mM concentration), add 100 μL of 0.1 g / mL potassium hydroxide solution. -1 Calcium chloride was used to obtain calcium alginate gel.
[0058] (4) Weigh 1 mg of AuNPs@ZIF-8-C obtained in Example 1, disperse it in 1 mL of ultrapure water, drop the AuNPs@ZIF-8-C dispersion onto the surface of the screen-printed electrode SPCE and dry it, then quickly drop calcium alginate gel onto the electrode surface to obtain a wearable non-enzymatic electrochemical sensor.
[0059] Example 4:
[0060] The wearable non-enzymatic electrochemical sensor prepared in Example 1 was used to perform electrochemical measurements in glucose solutions of different concentrations (10 μM, 50 μM, 100 μM, 150 μM, 200 μM, 250 μM, and 300 μM). The results are as follows. Figure 4 As shown, the current density at the electrode surface gradually increases with increasing glucose concentration, which is attributed to the oxidation of more glucose at the electrode surface, thereby increasing the current density.
[0061] Example 5:
[0062] When the wearable non-enzymatic electrochemical sensor prepared in Example 1 was used to detect electrochemical signals in glucose solutions of different concentrations, the current density j at the electrode surface showed a linear relationship with the Glu concentration. The results are as follows: Figure 5 As shown, the linear equation is: j = 0.1432c + 0.5838(R) 2 =0.9972), and the detection limit was 4.99 mM (S / N=3). The above results demonstrate that the wearable non-enzymatic electrochemical sensor can be successfully applied to the rapid and sensitive detection of Glu.
[0063] Example 6:
[0064] By detecting 300 μM glucose and the same concentration of Cl... - Na + The specificity of wearable non-enzymatic electrochemical sensors was studied by analyzing the electrochemical signal responses of urea and lactic acid on the electrode surface. The results are as follows: Figure 6 As shown, only glucose can significantly increase the current density on the electrode surface, which is due to the specificity of gold nanoparticles as glucose oxidation mimics.
[0065] Example 7:
[0066] The wearable non-enzymatic electrochemical sensor prepared in Example 1 was used for real-time monitoring of glucose in the sweat of volunteers. The current-time curve was performed using a constant voltage of 0.6V. Figure 7 As shown, the changes in electrical signals in the sweat of volunteers were measured, and the linear equation was: j = 0.1432c + 0.5838(R) 2From the equation (=0.9972), we can know that the glucose concentration in the sweat of a healthy volunteer is 80 μM.
[0067] Example 8:
[0068] The wearable non-enzyme electrochemical sensor prepared in Example 1 was combined with 10 6 CFU mL -1 After incubating Escherichia coli and Staphylococcus aureus in glucose solution at 37°C for 24 hours, the control sample and the sample to be tested were taken, diluted appropriately, and inoculated onto agar medium. After incubation at 37°C for 24 hours, colony counting was performed.
[0069] The results are as follows Figure 8 The diagram shows the bacterial growth before and after co-cultivation, demonstrating the antibacterial properties of the designed sensor and further illustrating its wearable performance.
Claims
1. A wearable non-enzymatic electrochemical sensor, characterized in that, The wearable non-enzymatic electrochemical sensor includes electrodes and gold nanoparticle-doped metal-organic framework and calcium alginate gel sequentially modified on the electrode surface. The method for preparing the wearable non-enzymatic electrochemical sensor includes the following steps: (1) Weigh gold nanoparticle solution, 2-methylimidazole and hexadecyltrimethylammonium bromide, mix them, add zinc acetate solution, let them stand after fully reacting, centrifuge, dry to obtain precipitate, calcine in nitrogen atmosphere to obtain gold nanoparticle-doped metal-organic framework, dissolve the gold nanoparticle-doped metal-organic framework in water to obtain gold nanoparticle-doped metal-organic framework dispersion. (2) Take the electrode, drop-coat the dispersion of gold nanoparticle-doped metal carbide organic framework, dry it, and then drop-add calcium alginate gel to obtain a wearable non-enzymatic electrochemical sensor.
2. The wearable non-enzymatic electrochemical sensor as described in claim 1, characterized in that, The electrode is a screen-printed electrode.
3. The method for preparing a wearable non-enzymatic electrochemical sensor as described in claim 1, characterized in that, Includes the following steps: (1) Weigh gold nanoparticle solution, 2-methylimidazole and hexadecyltrimethylammonium bromide, mix them, add zinc acetate solution, let them stand after fully reacting, centrifuge, dry to obtain precipitate, calcine in nitrogen atmosphere to obtain gold nanoparticle-doped metal-organic framework, dissolve the gold nanoparticle-doped metal-organic framework in water to obtain gold nanoparticle-doped metal-organic framework dispersion. (2) Take the electrode, drop-coat the dispersion of gold nanoparticle-doped metal carbide organic framework, dry it, and then drop-add calcium alginate gel to obtain a wearable non-enzymatic electrochemical sensor.
4. The preparation method according to claim 3, characterized in that, The preparation method of the gold nanoparticle solution in step (1) is as follows: weigh HAuCl4 solution, heat to boiling under vigorous stirring, add trisodium citrate solution, boil, and cool to room temperature.
5. The preparation method according to claim 4, characterized in that, The boiling time is 5-15 minutes; The volume ratio of the HAuCl4 solution to the trisodium citrate solution is 250:3~4; The concentration of the HAuCl4 solution is 0.01~0.1%, and the concentration of the trisodium citrate solution is 0.1~1%.
6. The preparation method according to claim 3, characterized in that, The volume-to-mass ratio of the gold nanoparticle solution, 2-methylimidazole, hexadecyltrimethylammonium bromide and zinc acetate solution in step (1) is 20-30 mL: 5-6 g: 1-5 mg: 20-30 mL; The concentration of the zinc acetate solution is 5-10 mM, and the concentration of hexadecyltrimethylammonium bromide is 5-10 μM.
7. The preparation method according to claim 3, characterized in that, The settling time mentioned in step (1) is 1~3 hours; The drying method is freeze-drying; The calcination temperature is 700~1000℃, and the calcination time is 1~4 h.
8. The preparation method according to claim 3, characterized in that, The preparation method of calcium alginate gel in step (2) is as follows: weigh sodium alginate and dissolve it in potassium hydroxide solution to obtain a mixed solution, add a crosslinking agent, and obtain calcium alginate gel.
9. The preparation method according to claim 8, characterized in that, The crosslinking agent is calcium chloride; The mass-to-volume ratio of sodium alginate, potassium hydroxide solution, and crosslinking agent is 1~5 mg:1 mL:100 μL; The concentration of the potassium hydroxide solution is 2-5 mM.
10. The application of a wearable non-enzymatic electrochemical sensor as described in claim 1 or 2 in real-time monitoring of glucose content in body fluids.