An electrochemical sensor, a preparation method and application thereof in detecting sweat triglyceride content

Abstract

The present application belongs to the field of analytical chemistry and electrochemistry, and particularly relates to an electrochemical sensor, a preparation method and application thereof in detection of sweat triglyceride content. A wearable sensor is prepared based on C-ZIF-67 / KB nanocomposite material, the sensor realizes detection of sweat triglyceride for the first time, and it is verified that sweat triglyceride level has high correlation with blood triglyceride level (correlation coefficient is 0.813, n=35). Through verification of a commercial colorimetric analysis kit, the sensor obtains a high correlation coefficient of 0.853 in detection of sweat triglyceride, which shows excellent accuracy.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of analytical chemistry and electrochemistry, and particularly relates to an electrochemical sensor, a preparation method and application thereof in detecting sweat triglyceride content. BACKGROUND

[0002] Cardiovascular disease (CVD) is a leading cause of death worldwide. Abnormal levels of blood lipids have been identified as key risk factors for atherosclerosis and coronary heart disease. The level of triglycerides is one of the important indicators for measuring the health status of the human body. Both too high or too low concentrations of triglycerides in the blood can indicate certain health problems. Accurate monitoring of triglyceride levels is of great importance for early diagnosis, prevention and treatment of diseases. However, current triglyceride monitoring mainly relies on invasive blood tests, and traditional clinical examination methods have many shortcomings. Patients need to personally visit medical institutions for treatment, which not only consumes time and energy, but also may bring inconvenience to patients with limited mobility. At the same time, invasive monitoring itself can cause certain discomfort and potential risks to patients. In addition, the low sampling frequency cannot capture the dynamic changes of triglyceride levels in time, and important information about the condition changes may be missed. For high-risk groups or patients who need long-term medication monitoring, frequent blood sampling not only increases the physical and mental burden, but also may lead to delayed treatment due to fluctuations in indicators during the detection interval.

[0003] In recent years, with the rapid development of microelectronics technology, nanotechnology and biosensor technology, wearable sensor technology has made significant breakthroughs. Wearable sensors are sensors that can be directly attached to the surface of the human body or integrated into wearable devices such as clothing, allowing real-time and continuous monitoring of physiological parameters. They have the advantages of small size, light weight, comfortable wearing, easy operation, etc., and can achieve non-invasive or minimally invasive monitoring of physiological signals. Currently, wearable sensors have been widely used in the monitoring of physiological parameters such as heart rate, blood pressure, body temperature, blood glucose, and have played an important role in health management, sports monitoring and disease diagnosis. Sweat is an important excretion of the human body, and its composition is complex, containing not only water and electrolytes, but also a variety of organic substances such as amino acids, glucose, urea, etc. In recent years, several studies have shown that sweat glucose is highly correlated with blood glucose, and different types of wearable sensors have been developed for daily monitoring of sweat glucose for the daily management of diabetes.

[0004] Despite the significant progress in wearable sensor technology for physiological monitoring, there are still many challenges in the detection of triglycerides. First, the low concentration of triglycerides in sweat and the interference from various factors make it difficult to detect. Second, there are still significant challenges in the practical application of wearable electrochemical sensors. Current research focuses on strategies such as material interface modification, flexible substrate structure optimization, and surface functionalization modification to improve the environmental adaptability and long-term stability of the sensor. On the other hand, how to establish a quantitative relationship between sweat triglycerides and blood triglycerides, and how to ensure the accuracy and reliability of the detection data, are also key issues that need to be addressed.

[0005] Therefore, the concentration of triglycerides in sweat is expected to be a potential indicator of blood triglyceride levels. Compared with blood sampling, sweat sampling has the advantages of non-invasiveness, convenience, and strong repeatability. By detecting the concentration of triglycerides in sweat through wearable sensors, it is expected to achieve indirect detection of blood triglyceride levels. SUMMARY

[0006] To overcome the shortcomings of the prior art, the present application provides the following technical solutions:

[0007] The first aspect of the present application is to provide a preparation method of a wearable electrochemical sensor, which comprises the following steps:

[0008] (1) Acid pretreatment of Ketjenblack (KB) to obtain acidified KB, and then in-situ growth of ZIF-67 / KB composite material C-ZIF-67 / KB;

[0009] (2) Screen-printed electrode preparation: using polyethylene terephthalate (PET) film as the substrate material, first printing the conductor and reference electrode with silver / silver chloride paste, then printing the counter electrode and working electrode with carbon paste, and finally printing the insulating layer with insulating ink;

[0010] The C-ZIF-67 / KB powder is placed in deionized water and uniformly dispersed by ultrasonic treatment to prepare a material dispersion liquid with a concentration of 1 mg / mL. Then, 2 μL of the dispersion liquid is dropped on the surface of the screen-printed electrode and dried at room temperature for standby.

[0011] (3) Triglyceride sensor preparation: functionalization treatment of the counter electrode: mixed enzyme solution of glycerol-3-phosphate oxidase, lipase and glycerol kinase, enzyme solution is dropped on the surface of the modified electrode, dried, and then chitosan solution is added for immobilization treatment, and dried at room temperature.

[0012] Further, the acidification pretreatment of step (1) is carried out by dispersing KB powder in a concentrated sulfuric acid / concentrated nitric acid mixed solution for reaction; after the system is cooled to room temperature, deionized water and anhydrous ethanol are used for centrifugal washing to neutral, and then dried in a vacuum drying box to obtain acidified KB;

[0013] In one specific embodiment, the mass-volume ratio of the KB powder to the concentrated sulfuric acid / concentrated nitric acid mixed solution is 4-6 mg:10 mL; preferably, the mass-volume ratio of the KB powder to the concentrated sulfuric acid / concentrated nitric acid mixed solution is 5 mg:10 mL;

[0014] In another specific embodiment, the reaction temperature is 80-100°C, and the reaction time is 10-14 hours; preferably, the reaction temperature is 90°C, and the reaction time is 12 hours;

[0015] In another specific embodiment, the washing condition is 7000-9000 rpm, 8-12 min / time; preferably, the washing condition is 8000 rpm, 10 min / time;

[0016] In another specific embodiment, the vacuum drying condition is 50-70°C, and the drying time is 10-14 hours; preferably, the vacuum drying condition is 60°C, and the drying time is 12 hours.

[0017] In another specific embodiment, the in-situ growth method is carried out by dissolving Co(NO3)2·6H2O and polyvinylpyrrolidone (PVP) in methanol, magnetically stirring to form a homogeneous solution A; dispersing acidified KB and 2-methylimidazole (2-MI) in another methanol by ultrasonic dispersion to form solution B; mixing the two solutions A and B, stirring vigorously, standing and aging, centrifugal washing with methanol and vacuum drying to obtain ZIF-67 / KB precursor; carbonizing the ZIF-67 / KB precursor in a tube furnace: gradually heating to 500-700°C under air atmosphere, and constant temperature calcination for 1-3 hours to finally obtain C-ZIF-67 / KB powder;

[0018] In another specific embodiment, the mass-volume ratio of Co(NO3)2·6H2O, PVP and methanol in solution A is 0.291 g:0.1 g:25 mL;

[0019] In another specific embodiment, the mass-volume ratio of acidified KB, 2-MI and methanol in solution B is 0.05 g:0.328 g:25 mL;

[0020] In another specific embodiment, the time of the vigorous stirring is 8-12 min, and the standing time is 20-30 hours.

[0021] In another specific embodiment, the methanol washing is performed at 5000-7000 rpm for 3-7 min; preferably, the temperature is increased at a rate of 5°C / min.

[0022] Further, the electrode pattern in step (2) comprises a working electrode with a radius of 1 mm, a reference electrode with a radius of 0.6 mm, and a counter electrode with a radius of 0.5 mm.

[0023] In another specific embodiment, after printing each functional layer, the electrode is placed in a 60°C oven for 30 min to ensure the stability and conductivity of each layer of material.

[0024] In another specific embodiment, the electrochemical performance of the electrode is tested by cyclic voltammetry to evaluate the reproducibility of different batches of electrodes.

[0025] Further, the chitosan solution in step (3) is prepared by dissolving 10 g of chitosan in deionized water containing 2% (v / v) acetic acid to prepare a 1% (w / v) chitosan solution.

[0026] In one specific embodiment, the concentration of the mixed enzyme solution of glycerol-3-phosphate oxidase, lipase, and glycerol kinase is 0.5-1.5 mg / mL; and the volume of the enzyme solution used for drop coating the modified electrode is 1-3 μL.

[0027] In another specific embodiment, all the sensor arrays are dried at 4°C in the dark for 12 h to complete the final preparation, and are stored at 4°C in a cold storage environment to maintain enzyme activity.

[0028] The second aspect of the present application provides a sensor prepared by the method of the first aspect.

[0029] The third aspect of the present application provides the use of the sensor of the second aspect in detecting triglycerides in sweat; preferably, the detection is non-disease diagnosis.

[0030] The fourth aspect of the present application provides the use of the sensor of the second aspect in preparing a device for detecting blood lipids; characterized in that the device is a wearable device, and the blood lipids are triglycerides.

[0031] The beneficial effects of the present application include:

[0032] 1) The present technology prepares a sensor based on C-ZIF-67 / KB nanocomposites, which has good stability and realizes the detection of triglyceride in sweat for the first time;

[0033] 2) Compared with bare SPCE, C-ZIF-67 / KB@SPCE exhibits good stability;

[0034] 3) The sensor obtains a high correlation coefficient of 0.853 in detecting sweat triglyceride through a commercial colorimetric analysis kit, showing excellent accuracy;

[0035] 4) The wearable sensor is used to measure the concentration of triglyceride in sweat, and the results are compared with the concentration of serum triglyceride. The results show that there is a high correlation between the concentrations of sweat and serum triglyceride, with a correlation coefficient of 0.813 (n=35). BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 Scanning electron microscope images of ZIF-67 (a), ZIF-67 / KB (b), C-ZIF-67 (c), and C-ZIF-67 / KB (d);

[0037] Figure 2 XRD spectra of ZIF-67 / KB and C-ZIF-67 / KB (a). Fourier transform infrared spectra of ZIF-67 / KB and C-ZIF-67 / KB nanomaterials (b). XPS spectra of ZIF-67 / KB and C-ZIF-67 / KB nanomaterials (c). High-resolution XPS spectra of cobalt (d);

[0038] Figure 3 Cyclic voltammograms (a) and electrochemical impedance curves (b) measured using bare SPCE and C-ZIF-67 / KB modified SPCE, and the electrolyte solution used is 0.1M KCl containing 5mM [Fe(CN)6] 3- / 4– as an electrochemical signal probe and buffer;

[0039] Figure 4 Standard curve detection graph;

[0040] Figure 5 Accuracy verification of the sensor in human sweat samples (n=25 biological replicates). The Pearson correlation coefficient is obtained by linear regression;

[0041] Figure 6 Stability graph detected by C-ZIF-67 / KB electrode, ZIF-67 / AgNWs electrode modified electrode and bare electrode for 12 consecutive days in 0.1M KCl solution containing 1mM [Fe(CN)6] 3- / 4- as a probe;

[0042] Figure 7 TG levels in sweat from different skin locations were assessed. Error bars represent SD of the mean of 5 healthy subjects;

[0043] Figure 8 Correlation of TG concentration in sweat and serum;

[0044] Figure 9 Box and whisker plot of TG levels in sweat and serum samples from healthy subjects (5) and hyperlipidemic subjects (5);

[0045] Figure 10 TG concentration in sweat and serum from hyperlipidemic subjects before and after drug administration. DETAILED DESCRIPTION

[0046] The concept and the resulting technical effects of the present application will be further described below in connection with specific embodiments. The methods are all conventional unless otherwise specified. The materials are all commercially available unless otherwise specified. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an undue limitation on the present application. It is to be expressly understood that the embodiments and features of the present application can be combined with each other, if not contradictory, in order to constitute additional embodiments of the present application.

[0047] Example 1 Sensor preparation

[0048] 1. Preparation of C-ZIF-67 / KB nanomaterials

[0049] 1.1 Acidification pretreatment of KB: 10 mg KB powder was accurately weighed and dispersed in 20 mL of a mixed solution of concentrated sulfuric acid and concentrated nitric acid (H2SO4 / HNO3 volume ratio 3:1) and reacted at 90°C for 12 hours. After the system cooled to room temperature, centrifugal washing (8000 rpm, 10 min / time) with deionized water and anhydrous ethanol was performed in sequence until neutral, and then dried in a vacuum drying oven (60°C, 12 h) to obtain acidified KB.

[0050] 1.2 In-situ growth method for preparing ZIF-67 / KB composite material: 0.291 g of Co(N03)2-6H20 and 0.1 g of polyvinylpyrrolidone (PVP) were dissolved in 25 mL of methanol to form a homogeneous solution A under magnetic stirring; 50 mg of acidified KB and 0.328 g of 2-methylimidazole (2-MI) were ultrasonically dispersed in another 25 mL of methanol to form solution B; the two solutions A and B were mixed and stirred vigorously for 10 min, then aged for 24 hours, and then washed by centrifugation (6000 rpm, 5 min) four times with methanol and vacuum dried to obtain ZIF-67 / KB precursor. The ZIF-67 / KB precursor was subjected to carbonization treatment in a tube furnace: programmed heating to 600°C at a heating rate of 5°C / min under air atmosphere, and constant temperature calcination for 2 hours, to finally obtain C-ZIF-67 / KB powder.

[0051] 2. Screen-printed electrode preparation

[0052] 2.1 Design and preparation of electrode pattern

[0053] The electrode pattern consisted of a working electrode with a radius of 1 mm, a reference electrode with a radius of 0.6 mm, and a counter electrode with a radius of 0.5 mm. The pattern was designed by computer-aided design (CAD) software and prepared by screen printing technology.

[0054] PET film was used as the base material. First, silver / silver chloride paste was used to print the conductor and reference electrode, then carbon paste was used to print the counter electrode and working electrode, and finally insulating ink was used to print the insulating layer.

[0055] After printing each functional layer, the electrode was placed in a 60°C oven for 30 minutes to ensure the stability and conductivity of each layer of material. The electrochemical performance of the electrode was tested by cyclic voltammetry, and the reproducibility of different batches of electrodes was evaluated.

[0056] 2.2 The C-ZIF-67 / KB nanomaterial powder obtained in step 1 was prepared into a 1 mg / mL aqueous dispersion, and 2 μL was dropped onto the surface of the screen-printed electrode and dried at room temperature for 4 hours.

[0057] 3. Preparation of triglyceride sensor

[0058] 3.1 10 g of chitosan was dissolved in deionized water containing 2% (v / v) acetic acid to prepare a 1% (w / v) chitosan solution. During the sensor construction, the electrode was functionalized with a mixed enzyme solution of glycerol-3-phosphate oxidase, lipase and glycerol kinase (total concentration 1 mg / mL), 2 μL of the enzyme solution was dropped on the surface of the modified electrode, and after drying, chitosan solution was added for immobilization, and dried at room temperature. All sensor arrays were dried at 4 °C in the dark for 12 h to complete the final preparation, and stored in a 4 °C refrigerator environment to maintain enzyme activity on a daily basis.

[0059] Figure 1 The morphology changes during the material preparation process were studied by field emission scanning electron microscopy system. As shown in FIG. 6a, ZIF-67 presents a relatively regular polyhedral structure, with smooth surface and uniform size. In contrast, the surface of ZIF-67 / KB is attached with KB particles, resulting in an irregular structure (FIG. 6b). After carbonization treatment, the size and polyhedral shape of ZIF-67 nanoparticles remain highly uniform, with a width of about 200 nm (FIG. 6c). For the C-ZIF-67 / KB sample, the hollow polyhedral shape is well preserved after heat treatment, but the surface is rougher, with nanoparticles attached (FIG. 6d). Figure 1 Figure 1 Figure 1 Figure 1

[0060] Figure 2 The crystal structure of ZIF-67 / KB hollow polyhedron was characterized by X-ray diffraction (XRD) technique (FIG. 7a). The analysis results show that the positions of the typical diffraction peaks at 7.9°, 10.5°, 12.8°, 15°, 16.7°, 18° and 26.7° in the XRD pattern are consistent with the literature reports, indicating that the prepared ZIF-67 / KB template has a high degree of phase purity. After calcination treatment, the XRD pattern further confirms that ZIF-67 / KB has been completely converted into Co3O4-like hollow polyhedron. In addition, the XRD pattern of the prepared C-ZIF-67 / KB hollow polyhedron shows characteristic peaks at 19°, 31°, 37°, 39°, 45°, 59° and 65°. These diffraction peaks are highly consistent with the standard XRD pattern of cubic Co3O4 (JCPDS No. 03065-3103), further verifying the crystal structure and phase purity of the material. Figure 2

[0061] Figure 2 ​​​​​In the infrared spectrum, b ZIF-67 / KB exhibits a Co-N stretching vibration band at 424 cm⁻¹. The presence of Co-N bonds is also observed in the C-ZIF-67 / KB structure. The CN bending vibration occurs at 992 cm⁻¹, while the CN stretching vibration shows an absorption band at 1142 cm⁻¹. C=N absorption peaks are observed at 756 cm⁻¹ and 1577 cm⁻¹. Furthermore, an O-H stretching vibration at 3296 cm⁻¹ and a C-H asymmetric stretching absorption band at 2922 cm⁻¹ are observed. After calcination, the absorption peak at 3442 cm⁻¹ is due to the stretching vibration of OH. 568 cm⁻¹ is a characteristic peak of Co-O, indicating the formation of a Co₃O₄-like structure.

[0062] Further analysis of the constituent elements and chemical bonds of hybrid porous carbon was conducted using X-ray photoelectron spectroscopy (XPS). For example... Figure 2 As shown in Figure c, four distinct peaks were observed at 288.08, 401.08, 532.08, and 780.08 eV, corresponding to the characteristic binding energies of C1s, N 1s, O 1s, and Co 2p in C-ZIF-67 / KB, respectively, indicating the presence of Co-N doping in the material. Figure 2 In d, the Co 2p3 / 2 spectrum shows two distinct peaks at 777.8 and 779.9 eV, which indicate that the Co on the surface is mainly Co3O4.

[0063] Figure 3 The preparation process of screen-printed carbon electrodes modified with nanocomposite materials was systematically studied through electrochemical performance testing. In the experiment, bare SPCEs or SPCEs modified with different nanomaterials were immersed in a 0.1M KCl solution containing [Fe(CN)6]3- / 4- as redox probe ions. The redox reactions on the modified electrode surface were measured using cyclic voltammetry and electrochemical impedance spectroscopy. Figure 3 As shown in figure a, the C-ZIF-67 / KB modified electrode exhibits a higher peak current response compared to the ZIF-67 / KB modified electrode, indicating a significant improvement in charge transfer rate, thereby achieving a fast and sensitive electrochemical signal response.

[0064] The interfacial properties of SPCE surfaces with different modifications were further investigated by measuring the EIS curves, such as... Figure 3As shown in b, the charge transfer resistance (Rct) reflects the electron transfer kinetics of redox probe ions at the electrode interface, and its value can be calculated from the diameter of the semicircle in the Nyquist plot. When the SPCE surface is modified with different materials, a larger semicircular region appears in the Nyquist plot, indicating that charge transfer is hindered. Experimental results show that the C-ZIF-67 / KB modified electrode has a lower Rct value than ZIF-67 / KB. Since Rct is inversely related to the redox peak current, and their trends are opposite, the EIS results are highly consistent with the cyclic voltammetry results. This demonstrates that C-ZIF-67 / KB has excellent electrochemical activity.

[0065] Figure 4 A standard curve for triglycerides was tested in phosphate buffer solution. Figure 4 As shown in Figure a, the peak current intensity decreases linearly with decreasing triglyceride concentration (CTG), indicating a good linear relationship between the triglyceride response current (ITG) and concentration (CTG). Within the concentration range of 0.1 μM to 500 μM, the linear relationship can be expressed by the formula ITG = 0.00005264CTG + 0.01961(R). 2 =0.983) Description ( Figure 4 b).

[0066] Example 2: Characterization Test of Triglyceride Sensor Detection Performance

[0067] The optimal potentiostat for it assays was optimized in analyte buffer systems of varying concentrations. Under these optimal potential conditions, the it curves of the Enzyme-C-ZIF-67 / KB@SPCE sensing platform were tested in phosphate buffer solutions (0.01 M, pH 7.4) containing triglycerides (0.1–500 μM). The detection performance of the sensing platform for the target analyte was evaluated by measuring the change in current response over time. The accuracy of the sensor in sweat detection was assessed using a commercial ELISA kit.

[0068] The results are as follows Figure 5 As shown, the results indicate that the sensor achieved a high correlation coefficient of 0.853 when detecting triglycerides, demonstrating that the sensor's measurement results are highly consistent with the standard colorimetric method, thus verifying the reliability of its measurement.

[0069] Example 3: Stability Characterization Test of Triglyceride Sensor

[0070] To further evaluate the long-term detection stability of the sensor, cyclic voltammetry was performed every other day for 12 days using a single sensor array. The degradation of the sensor's detection performance was observed by monitoring changes in the oxidation peak height.

[0071] Results as shown in Figure 6 Figure 8, C-ZIF-67 / KB@SPCE exhibited good stability compared with bare SPCE. In the 12-day continuous test, C-ZIF-67 / KB@SPCE showed a lower degree of electrode attenuation, and its detection performance was retained by 85%.

[0072] Example 4 Practical application test

[0073] 1. Human subject recruitment

[0074] The verification and evaluation of the sweat sensor were carried out through the participation of human subjects, in accordance with all ethical regulations under the agreement approved by the Institutional Review Board of China Agricultural University (CAUHR-20250307). The subjects participating in the study (age range 18-65 years old) were recruited through advertisements from the campus and neighboring communities. Among them, 8 healthy subjects and 5 hyperlipidemia subjects were recruited. The inclusion criteria for healthy subjects were 18≤age≤66; physically and mentally healthy, 18.5≤BMI≤25; plasma triglycerides <1.7 mmol / L; and no participation in other research projects in the two months before the study. The inclusion criteria for hyperlipidemia patients were: 18≤age≤65; physically and mentally healthy, 18.5≤BMI≤29.9; plasma triglycerides >2.6 mmol / L; and no participation in other research projects in the two months before the study. The exclusion criteria for subjects were: kidney disease / dysfunction, liver disease, thyroid disease (hyperthyroidism / hypothyroidism, etc. abnormal hormone levels); cancer (breast cancer, liver cancer, gastric cancer, lung cancer, etc. tumor); excessive alcohol consumption, smokers (more than 855 mL of beer, 360 mL of wine, or 90 mL of hard liquor per day, or more than one pack per day); women preparing for pregnancy, pregnant and lactating women; those who have undergone major surgery in the past 3 months; those who have experienced significant weight gain or loss in the past 6 months. All subjects gave written informed consent before participating in the study.

[0075] 2. Sample processing and detection of subjects

[0076] After the blood sample of the subject was collected by intravenous blood collection, it was left to stand at room temperature for 30 minutes, and then centrifuged at a speed of 3000 rpm for 10 minutes to separate the serum. After centrifugation, the supernatant was aliquoted and stored for later use. For the sweat samples collected by medical patches, centrifugation was performed at a speed of 5000 rpm for 15 minutes for separation and processing, and then aliquoted and stored for later use. All samples were stored at -80°C to ensure the stability of the samples and the reliability of subsequent analysis.

[0077] Results as shown in Figure 7 Figure 9: Sweat samples were collected from three locations on the body and detected using wearable sensors. The results showed that triglyceride secretion could be detected in the sweat from these parts.

[0078] To analyze the collected blood and sweat samples, the present study employed ELISA kits for blood samples and wearable sensors for sweat samples.

[0079] Results, as shown in Figure 8 Figure 2, revealed a high correlation between sweat and serum triglyceride concentrations, with a correlation coefficient of 0.813 (n = 35). This result indicated that the triglyceride level in sweat could potentially serve as a reliable surrogate indicator of blood triglyceride levels for non-invasive monitoring of hyperlipidemia.

[0080] Example 5 Human health management trial of wearable triglyceride sensor

[0081] To evaluate the potential application of the prepared wearable sensor in hyperlipidemia management, we recruited 5 hyperlipidemia patients and 5 healthy subjects in a nearby community. All subjects were strictly screened to ensure that they met the research criteria. Before the start of the study, the 5 hyperlipidemia patients had not received any lipid-lowering drug treatment for at least 24 hours to ensure complete drug metabolism and avoid interference with the experimental results. All subjects collected sweat samples and blood samples after overnight fasting. Sweat samples were detected by wearable sensor patches, while blood samples were tested using ELISA kits. During the physical test, medical patches were used to collect sweat samples from the subjects regularly to further analyze and verify the accuracy of the sensor.

[0082] To study the effect of lipid-lowering drugs on triglyceride levels in serum and sweat, hyperlipidemia subjects collected sweat and blood samples before and after regular use of lipid-lowering drugs. At the start of the experiment, patients were prohibited from taking medication within 24 hours of sampling to ensure complete drug emptying, and then sweat and blood samples were collected after overnight fasting. During the experiment, the subjects regularly took lipid-lowering drugs as prescribed and maintained normal dietary habits. On the 30th day after overnight fasting, sweat and blood samples were collected again to observe the long-term effect of the drugs on triglyceride concentration.

[0083] Results, as shown in Figure 9 Figure 3, revealed that the sweat triglyceride levels of hyperlipidemia subjects (n = 5) were higher than those of healthy subjects (n = 5), and their serum triglyceride levels also showed a similar trend. Among them, the average sweat triglyceride level of healthy subjects was 3.1 μΜ, while the average sweat triglyceride level of hyperlipidemia subjects was 30.8 μΜ.

[0084] Figure 10As shown, after intervention, from the overall level, for the subjects (n=3) who regularly take lipid-lowering drugs, the triglyceride levels in serum and sweat were detected after 30 days of taking the drugs, and the serum triglyceride levels were reduced by 50.12%, and the mean value of sweat triglyceride concentration was reduced from 82.42 μM to 44.37 μM, with a reduction of 53.83% Figure 10 ). The change trend of triglyceride in sweat and serum triglyceride was consistent.

[0085] The above-described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments of the present application, other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

Claims

1. A method of preparing a wearable electrochemical sensor, characterized by, The method comprises the following steps: (1) acidizing KB to obtain acidized KB, and then using in-situ growth method to prepare ZIF-67 / KB precursor, and carbonizing the ZIF-67 / KB precursor in a tube furnace to obtain C-ZIF-67 / KB; (2) electrode pattern printing: using PET film as the base material, first printing the guide wire and reference electrode by using silver / silver chloride paste, then printing the counter electrode and working electrode by using carbon paste, and finally printing the insulation layer by using insulation ink; (3) triglyceride sensor preparation: functionalizing the counter electrode: mixing enzyme solution of glycerol-3-phosphate oxidase, lipase and glycerol kinase, dropping the mixed enzyme solution on the surface of the modified electrode, drying, and then adding chitosan solution for immobilization treatment, and drying at room temperature.

2. The method of claim 1, wherein, The operation of the acidizing pretreatment of step (1) is: dispersing KB powder in a concentrated sulfuric acid / concentrated nitric acid mixed solution for reaction; after the system is cooled to room temperature, deionized water and anhydrous ethanol are used for centrifugal washing to neutral, and then dried in a vacuum drying box to obtain acidized KB.

3. The method of claim 2, wherein, The operation of the in-situ growth method is: dissolving Co(NO3)2·6H2O and PVP in methanol to form a homogeneous solution A by magnetic stirring; dispersing acidized KB and 2-methyl imidazole in another methanol by ultrasonic to form solution B; mixing the two solutions A and B, stirring vigorously, standing and aging, centrifugal washing with methanol and vacuum drying to obtain ZIF-67 / KB precursor; and carbonizing the ZIF-67 / KB precursor in a tube furnace: gradually heating to 500-700℃ under air atmosphere, and constant temperature calcination for 1-3 hours to finally obtain C-ZIF-67 / KB powder.

4. The method of claim 1, wherein, The electrode pattern in step (2) is composed of a working electrode with a radius of 1 mm, a reference electrode with a radius of 0.6 mm and a counter electrode with a radius of 0.5 mm; after printing each functional layer, the electrode is placed in a 60℃ oven for curing for 30 minutes to ensure the stability and conductivity of each layer of material.

5. The method of claim 1, wherein, The preparation of the chitosan solution in step (3) is: dissolving 10 g of chitosan in deionized water containing 2% (v / v) acetic acid to prepare 1% (w / v) chitosan solution.

6. The method of claim 5, wherein, The concentration of the mixed enzyme solution of glycerol-3-phosphate oxidase, lipase and glycerol kinase is 0.5-1.5 mg / mL; the volume of the mixed enzyme solution used for dropping and coating the modified electrode is 1-3 μL.

7. The sensor prepared by the method of any one of claims 1-6.

8. A wearable device for detecting triglycerides in sweat, characterized in that, The device contains the sensor of claim 7.

9. The sensor of claim 7 is used for detecting triglyceride in sweat; the detection is non-disease diagnosis detection.

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