Stable and durable wearable sweat and sugar electrochemical sensor
By preparing a sensing interface between ZIF-90@GOx composite material and conductive gel liquid on the surface of a carbon electrode, the problem of insufficient accuracy and stability of wearable electrochemical sensors in outdoor environments was solved, achieving high sensitivity and durability in sweat sugar detection.
Patent Information
- Application Number
- CN202511846423.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-01
- Publication Date
- 2026-01-23
AI Technical Summary
Existing wearable electrochemical sensors lack accuracy, stability, and durability in complex outdoor environments, and are particularly affected by light and environmental factors, and have poor conductivity at the sensing interface.
A sensing interface was formed on the surface of a carbon electrode using ZIF-90@GOx composite material and conductive gel liquid. The sensor was prepared by in-situ gelation technology and combined with Prussian blue nanoparticles to improve conductivity and enzyme environmental tolerance.
It improves the sensor's detection sensitivity and stability, enhances its adaptability and durability to the environment, and enables it to maintain high-efficiency monitoring performance in complex outdoor environments.
Smart Images
Figure CN121370157A_ABST
Abstract
Description
I. TECHNICAL FIELD
[0001] The present application relates to the technical field of electrochemical sensors, and particularly relates to a stable and durable wearable sweat glucose electrochemical sensor. II. BACKGROUND
[0002] Wearable electrochemical sensors have been widely used in physiological index analysis of various biological fluids such as sweat, saliva, tears and urine due to their small size, convenient carrying and real-time monitoring. Studies have shown that there is a good correlation between sweat and blood glucose levels, and sweat glands are distributed throughout the body surface and are easy to collect non-invasively, making the development of non-invasive sweat glucose detection methods and devices a current research hotspot. In recent years, with the development of electronic information technology, a number of wearable biosensors for real-time sweat glucose monitoring have been introduced, which has promoted the progress in this field. However, such sensors still face great challenges in clinical translation, especially when used in complex outdoor environments. For example, long-term outdoor light exposure can cause local thermal effects in the sensor, which directly leads to a decrease in detection accuracy. In addition, light radiation can degrade key components of the sensor, reducing its mechanical stability and sensing performance, and ultimately shortening its service life. In addition, wearable biosensors also face challenges in terms of storage stability and environmental tolerance to temperature, pH and humidity.
[0003] Metal-organic frameworks (MOFs) are a class of porous crystalline materials with adjustable pore size, high specific surface area, excellent stability and inherent biocompatibility, making them ideal carriers for enzyme immobilization. MOF@enzyme composites constructed based on these characteristics not only inherit the structural advantages of MOFs, but also show wide application potential in the field of wearable biosensors. However, the electrochemical sensing interface based on MOFs has poor conductivity. To solve this problem, conductive materials such as multi-walled carbon nanotubes, graphene or metal nanoparticles are often introduced. However, such materials not only may block the MOF pores and damage their inherent advantages, but also are easily detached due to physical adsorption or embedding on the electrode surface, which may compromise the stability of the sensor. III. SUMMARY
[0004] The present application aims to provide a wearable sweat glucose electrochemical sensor with simple preparation, high detection sensitivity and stability.
[0005] The present application can be achieved by the following technical solutions:
[0006] A stable and durable wearable sweat glucose electrochemical sensor, the sensing interface of the sensor is prepared by sequentially dropping glucose sensing solution and film forming solution on the surface of the carbon electrode Figure 1 ); wherein the glucose sensing solution is obtained by mixing zeolite imidazolate framework-90 (ZIF-90) composite material loaded with glucose oxidase, prussian blue nanoparticles (PBNPs) and conductive gel solution in a certain proportion, and the film forming solution is obtained by mixing ammonium persulfate and tetramethyl ethylenediamine in a certain proportion; when the sweat sample covers the surface of the above-mentioned sensor, the ZIF-90@GOx on the sensing interface oxidizes the glucose in the sweat, the generated hydrogen peroxide reacts with the prussian blue nanoparticles to generate an electric current signal on the electrode Figure 2 ), and finally the glucose in the sweat is quantitatively analyzed based on the standard curve method.
[0007] The above-mentioned ZIF-90@GOx composite material is prepared by rapidly adding Zn(NO3)2 solution into a mixed solution containing imidazole-2-formaldehyde, polyvinylpyrrolidone and glucose oxidase under stirring at room temperature.
[0008] The above-mentioned ZIF-90@GOx composite material uses imidazole-2-formaldehyde as a ligand, zinc ions as a metal node and polyvinylpyrrolidone as a stabilizer.
[0009] The above-mentioned carbon working electrode can be a disposable screen-printed carbon electrode, which can be a glassy carbon electrode or a graphite electrode.
[0010] The above-mentioned prussian blue nanoparticles are prepared by dropwise adding K3[Fe(CN)6] into an acetic acid solution containing FeCl2, poly(diallyldimethylammonium chloride) and chitosan.
[0011] The above-mentioned conductive gel solution is prepared by mixing poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid), acrylamide and N,N'-methylenebisacrylamide in a certain proportion.
[0012] Compared with the prior art, the present application has the following beneficial effects:
[0013] (1) The present application uses in-situ gel generation technology to prepare a "ZIF-90@GOx / conductive gel" sensing interface on the surface of the electrode, which effectively improves the use stability and durability of the glucose sensor.
[0014] (2) The present application uses metal framework material to load GOx, which effectively improves the environmental tolerance of the enzyme, so that the prepared glucose sensor has superior environmental adaptability and durability.
[0015] (3) The present application uses conductive hydrogel to replace traditional chitosan to prepare a sensing interface, effectively catalyzing the electron transfer on the surface of the electrode, and improving the detection sensitivity of the glucose sensor. IV. BRIEF DESCRIPTION OF DRAWINGS
[0016] Figure 1 . The preparation schematic diagram of the sensing interface of the sweat glucose electrochemical sensor according to the present application;
[0017] Figure 2 . The principle diagram of the electrochemical sensor for detecting sweat glucose according to the present application;
[0018] Figure 3 . The (a) amperometric response and (b) calibration curve of the sweat glucose electrochemical sensor according to the present application for detecting glucose;
[0019] Figure 4 . The detection sensitivity of the sweat glucose electrochemical sensor according to the present application under (a) different pH and (b) different temperature conditions;
[0020] Figure 5 . The detection sensitivity of the sweat glucose electrochemical sensor according to the present application within 170 days;
[0021] Figure 6 . The selectivity of the glucose sensor: the chronoamperometric response curve of the glucose sensor under the injection of different concentrations of interferents and 50 μM glucose;
[0022] Figure 7 . The calibration curve of (a) six batches and (b) six glucose sensors prepared in the same batch according to the present application;
[0023] Figure 8 . The continuous response of the sensor according to the present application to 100 μM glucose under a flow state;
[0024] Figure 9 . The (a) amperometric response and (b) calibration curve of the sweat glucose electrochemical sensor according to the present application for detecting glucose in artificial sweat;
[0025] Figure 10 . (a) The change curve of the surface temperature of the sweat glucose electrochemical sensor according to the present application under a continuous 10-hour outdoor environment (sunny summer, 10:00 am to 8:00 pm); (b) the standard curve of the glucose detection measured by the sweat glucose electrochemical sensor according to the present application after being exposed to the outdoor environment for 10 hours;
[0026] Figure 11 . The glucose detection amperometric response curve and the standard curve thereof of the control sensor before and after being exposed to the outdoor environment for 10 hours;
[0027] Figure 12The detection sensitivity of the sweat sugar electrochemical sensor described in this invention after undergoing 1000 bending / recovery cycles at different angles. V. Detailed Implementation Methods
[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are preferred embodiments of this invention and are merely illustrative of the invention, not intended to limit it.
[0029] like Figure 1 As shown, a glucose electrochemical sensor was prepared using disposable screen-printed electrode sheets as the substrate electrode. The preparation process included the preparation and modification of glucose sensing solution and film-forming solution.
[0030] Preparation of the glucose sensing solution: First, 0.5M acrylamide and 0.2MN,N′-methylenebisacrylamide were dissolved in 0.067wt% poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) aqueous solution and the volume was adjusted to 15mL to obtain a conductive gel solution; then, 371.25mg imidazole-2-carboxaldehyde, 50mg polyvinylpyrrolidone and 25mg GOx were dispersed in 25mL of ultrapure water, and then 3mL of 0.653M Zn(NO3)2 solution was quickly added. The mixture was stirred at room temperature for half an hour. After the reaction was completed, the mixture was centrifuged and washed to obtain ZIF-90@GOx, which was then dispersed in the conductive gel solution; in addition, Fe 2+ Mix thoroughly with the poly(diallyldimethylammonium chloride) solution, then add (FeCN6) dropwise. 3- Prussian blue nanoparticles (PBNPs) with a particle size of about 2-6 nm were prepared by stirring the reaction at room temperature for 1 hour and dispersed in conductive gel liquid. Finally, the ZIF-90@GOx, PBNPs solution and conductive gel liquid prepared above were mixed evenly according to a certain volume to obtain glucose sensing liquid.
[0031] Preparation of the film-forming solution: 0.02M ammonium persulfate solution and tetramethylethylenediamine are mixed at a volume ratio of 9:1 to obtain the film-forming solution.
[0032] Preparation of the aforementioned sweat glucose electrochemical sensor: 4 μL of glucose sensing solution and 1 μL of film-forming solution were sequentially added to the surface of the carbon working electrode and dried in a desiccator at room temperature to obtain the sweat glucose electrochemical sensor.
[0033] The mechanism by which the electrochemical sensor detects glucose in sweat is as follows: ZIF-90@GOx on the sensing interface oxidizes glucose in sweat, and the generated hydrogen peroxide reacts with Prussian blue nanoparticles to produce a current signal on the electrode. Figure 2), and finally the glucose in the sweat was quantitatively analyzed based on the standard curve method.
[0034] The detection of glucose by the sweat glucose electrochemical sensor: a batch of the above-mentioned sweat glucose electrochemical sensors were prepared in parallel, connected with an electrochemical workstation, and the chronoamperometry was used to detect the current signals of glucose with different concentrations at 0 V potential ( Figure 3 a), and the standard curve of the current signals and the glucose concentration was established ( Figure 3 b), and the results showed that the prepared sweat glucose electrochemical sensor had a good linear response to glucose in the range of 1-300 μM.
[0035] Evaluation of the influence of pH and temperature environment on the detection performance of the sensor: a batch of the above-mentioned sweat glucose electrochemical sensors were prepared in parallel, and were respectively placed in different pH sample solutions or under different temperature conditions, and the chronoamperometry was used to detect the current signals of glucose with different concentrations in the range of 1-300 μM at 0 V potential, and the standard curve was established to investigate the change of the detection sensitivity with pH and temperature, and the results showed that, compared with the control sensor prepared by simply mixing GOx and ZIF-90 (bare GOx+ZIF-90) Figure 4 b, d), the sensor of the application in which the GOx was encapsulated in the ZIF-90 framework could realize stable and reliable glucose detection in a wide range of pH 4-8 ( Figure 4 a) and temperature 20-50℃ ( Figure 4 c), which indicated that it was suitable for daily use environment and did not need additional temperature or pH compensation.
[0036] Evaluation of the storage stability of the sweat glucose electrochemical sensor: a batch of sensors were prepared in parallel, and the standard curve of glucose with different concentrations in the range of 1-300 μM was detected at 0 day, 20 days, 40 days, 60 days, 80 days, 100 days, 140 days and 170 days, respectively, to investigate the change of the detection sensitivity of the sensor with the storage time, and the results showed that the detection sensitivity of the sensor remained at about 95% of the initial value within 170 days of storage at room temperature, which showed good storage stability. Figure 5
[0037] Evaluation of the selectivity of the electrochemical sensor: the sensor had a high selective response to glucose in the presence of common sweat interferents. Figure 6
[0038] Evaluation of the preparation repeatability of the electrochemical sensor: six batches ( Figure 7 a) or six sensors prepared in the same batch ( Figure 7 b) The sensor showed a standard curve for glucose in the range of 1-300 mM with a deviation of less than 3% and 5% for the detection sensitivity, respectively, indicating that the sweat glucose electrochemical sensor had good preparation repeatability.
[0039] The continuous detection performance of the sweat glucose electrochemical sensor was evaluated: the current retention rate of the sensor was 98% after 8 hours of detection of 100 mM glucose solution under flow conditions, Figure 8 ), indicating that the sweat glucose electrochemical sensor had excellent continuous detection performance.
[0040] The sweat glucose electrochemical sensor was evaluated for detection of glucose in artificial sweat: a batch of sensors prepared in parallel was placed in artificial sweat, and a standard curve was established by detecting the current signal of glucose in the range of 1-300 mM at a potential of 0 V using chronoamperometry, with a detection sensitivity deviation of less than 5% ( Figure 9 ), which was comparable to the performance of detection of glucose in a phosphate buffer solution.
[0041] The environmental tolerance of the sweat glucose electrochemical sensor was evaluated: a batch of sensors prepared in parallel was placed in an outdoor light environment in sunny weather (the sensors were fixed to an experimental platform 1.0 meters (± 0.05 meters) above the ground to ensure that the sensors were completely exposed to natural light during the entire experiment, and there were no obstructions around the platform), from 10:00 in the morning to 8:00 in the evening. A portable temperature recorder (Elitech RC-4) was used to continuously monitor the temperature of the electrode surface in real time, with the temperature probe directly contacting the electrode surface and a sampling interval of 10 minutes Figure 10 a) After 10 hours of outdoor placement, the sensor was used to detect the current signal of glucose in the range of 1-300 mM, and a standard curve was established, with a sensitivity of 95% of the initial value ( Figure 10 b), which was significantly better than the control group (bare GOx + ZIF-90) Figure 11 ), indicating that the sensor had good environmental tolerance.
[0042] The mechanical robustness of the sweat glucose electrochemical sensor was evaluated: a batch of sensors prepared in parallel was subjected to 1000 bending-recovery experiments. Subsequently, the standard curve of the sensor in the glucose concentration range of 1-300 mM was determined, with a sensitivity of more than 85% of the initial value ( Figure 12 ), which indicated that the sensor had good mechanical robustness and could meet the actual needs of wearable devices for resistance to deformation.
[0043] The device embodiments described above are merely illustrative, the terms and expressions used are used as illustrations and not limitations, and it is not intended that any equivalents of the features or parts shown and described be excluded from the use of these terms and expressions.
Claims
1. A stable and durable wearable sweat glucose electrochemical sensor, characterized in that... The fabrication of the sensor's sensing interface includes the following steps: First, a glucose sensing solution, obtained by mixing a zeolite imidazole ester framework-90 (ZIF-90@GOx) composite material loaded with glucose oxidase, Prussian blue nanoparticles (PBNPs), and conductive gel liquid, was drop-coated onto the surface of a carbon working electrode. Then, the film-forming solution obtained by mixing ammonium persulfate and tetramethylethylenediamine is drop-coated onto the surface of the carbon working electrode.
2. The sensor according to claim 1, wherein, The ZIF-90@GOx composite material was prepared by mixing imidazole-2-formaldehyde, polyvinylpyrrolidone, glucose oxidase and Zn(NO3)2 at room temperature.
3. The sensor according to claim 1, wherein, The Prussian blue nanoparticles were prepared by dropwise addition of K3[Fe(CN)6] to an acetic acid solution containing FeCl2, poly(diallyldimethylammonium chloride) and chitosan.
4. The sensor according to claim 1, wherein, The conductive gel liquid is prepared by mixing poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid), acrylamide and N,N'-methylenebisacrylamide.
5. The sensor according to claim 1, characterized in that... The ZIF-90@GOx sensor interface oxidizes glucose in sweat, generating hydrogen peroxide which reacts with Prussian blue nanoparticles and then transfers electrons to the electrodes to produce a current signal.