A method of manufacturing a wearable sensor
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- QINGDAO UNIV OF SCI & TECH
- Filing Date
- 2023-02-21
- Publication Date
- 2026-06-30
Smart Images
Figure CN116087294B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of wearable electrochemical sweat sensor technology, and more specifically to a method for preparing a wearable sensor. Background Technology
[0002] Wearable devices and sensors have gained significant attention due to their ability to monitor human physiological information in real time.
[0003] Currently, wearable devices primarily track respiratory rate, body movement, and electrocardiograms, but cannot provide information at the molecular level. This challenge has spurred the rapid development of wearable electrochemical sensors, offering a window into the non-invasive detection of analytes in biofluids. Non-invasive monitoring is difficult to achieve in different types of biofluids, particularly in blood and interstitial fluids. Furthermore, compared to tears, saliva, and urine, sweat contains a wealth of essential indicators related to human physiological states, including various molecules and biomolecules (uric acid, ascorbic acid, and proteins), as well as metabolites (lactic acid and urea) and electrolytes (K+ and Na+). In particular, tyrosine (Tyr), a semi-essential amino acid, has a physiological concentration range of 6-240 μM in sweat; abnormal Tyr concentrations are associated with various diseases such as hypertyrosinemia, chronic low-grade inflammation, liver disease, and bulimia nervosa. However, electrochemical monitoring of Tyr is always susceptible to pH changes, and the pH of human sweat is easily affected by health conditions. Therefore, developing wearable sweat sensors to reliably and accurately detect tyr is of great significance.
[0004] Since wearable electrochemical sweat devices come into close contact with human skin, flexible materials with good conductivity and biocompatibility are essential when designing such sensors. Therefore, conductive polymer hydrogels have become ideal materials for sweat detection due to their excellent biocompatibility, large three-dimensional elastic cross-linked polymer network, good sweat storage capacity, adjustable mechanical properties, and good electrocatalytic properties. Among them, the conductive polymer polyaniline (PANI) exhibits interesting pH and Tyr sensing properties, which are useful for identifying Tyr and pH values in sweat. However, PANI-based hydrogels with good conductivity, antibacterial properties, and mechanical properties still require further exploration.
[0005] Meanwhile, as a wearable sensor for real-time sweat detection, the sweating process is crucial. Sweating can depend on environmental conditions (such as temperature and humidity), activity level, and chemical stimuli. While exercise is always used to induce sweating, it's difficult to meet the needs of individuals requiring on-demand sweat analysis and those in sedentary states. Therefore, appropriate sweat stimulation methods are needed to induce sweating in a controlled manner for in-situ detection. Iontophoresis, a routine process for delivering chemicals (such as pilocarpine), can stimulate sweat glands to produce sweat by applying a barely perceptible localized current to the skin. Therefore, integrating iontophoresis electrodes as a sweat induction module is key to achieving in-situ sweat analysis in sweat sensor systems.
[0006] Therefore, how to prepare a wearable sensor based on a multifunctional conductive hydrogel for simultaneously and accurately detecting pH and Tyr concentration in sweat is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention
[0007] In view of this, the purpose of this invention is to provide a method for fabricating a wearable sensor to overcome the shortcomings of the prior art. This sensor is a highly integrated, flexible wearable sweat sensor capable of successfully detecting pH and Tyr concentration in sweat.
[0008] To achieve the above objectives, the present invention adopts the following technical solution:
[0009] A method for fabricating a wearable sensor specifically includes the following steps:
[0010] (1) Preparation of TA-Ag nanoparticles
[0011] First, tannic acid (TA) powder was dissolved in water to obtain a tannic acid solution; then, silver nitrate (AgNO3) powder was dissolved in water to obtain a silver nitrate solution; the tannic acid solution and the silver nitrate solution were then mixed and stirred; finally, the mixture was centrifuged and washed to obtain TA-Ag nanoparticles.
[0012] (2) Preparation of TA-Ag-CNT-PANI hydrogel
[0013] First, ammonium persulfate (APS), carbon nanotubes (CNTs), and TA-Ag nanoparticles were dissolved in water to obtain solution A. Then, 3-aminophenylborate (ABA) was dissolved in hydrochloric acid, followed by the addition of aniline and water to obtain solution B. Next, solution B was added dropwise to an aqueous solution of polyvinyl alcohol (PVA) under magnetic stirring to obtain solution C. Finally, solution A was added to solution C and stirred rapidly to obtain TA-Ag-CNT-PANI hydrogel, which was then ready for use.
[0014] (3) Preparation of agarose hydrogel
[0015] First, dissolve agarose in potassium phosphate buffer and stir continuously until completely dissolved. Then pour it onto a mold and cool to room temperature to obtain agarose hydrogel for later use.
[0016] (4) Construction of wearable electrode array
[0017] A wearable electrode array is composed of an ion-importing electrode and an electrochemical sensor; wherein, the electrochemical sensor has a three-electrode system, including an Ag / AgCl reference electrode, a carbon counter electrode, and a carbon working electrode;
[0018] (5) Modification of wearable electrode arrays
[0019] First, TA-Ag-PANI-CNT hydrogel is drop-coated onto the carbon working electrode; then, before electrical stimulation, agarose hydrogel is cut into the same size as the ion-importing electrode and covered onto the ion-importing electrode; finally, pilocarpine solution is drop-into the agarose hydrogel and held in place, thus obtaining the wearable sensor.
[0020] The application principle of the wearable sensor of this invention:
[0021] This invention prepares an iontophoresis system and an electrochemical sensing system based on pilocarpine, and couples them onto an electrochemical sensing electrode array on a single wearable detection patch. Figure 1 This device is designed to achieve localized sweat irritation and accurate Tyr detection. The iontophoresis electrode (i.e., the IP electrode, consisting of an Ag cathode and an Ag anode) and the three-electrode sensing system (including an Ag / AgCl reference electrode, a carbon counter electrode, and a carbon working electrode) are mass-produced using screen printing technology. Figure 2 The process involves printing serpentine wires and electrodes onto a flexible polyimide (PI) substrate using a 300-mesh screen, followed by printing an insulating layer in the same manner. The electrode array is then dried at 60°C for 30 minutes. The IP electrode has an anode width of 1 cm and a length of 2 cm, and a cathode width of 1 cm and a length of 1 cm. The agarose hydrogel loaded on the IP electrode consists of agarose and potassium phosphate buffer solution to prevent potential pH changes on the epidermis due to ion accumulation at sampling points during repeated sensing. Furthermore, the agarose gel serves as the anode drug storage layer, pre-loaded with a 3% pilocarpine solution. Upon energization, the anode repels positively charged pilocarpine drug from entering the skin, thereby inducing sweating. Figure 3 The TA-Ag-CNT-PANI hydrogel was modified on a carbon working electrode using a drop-coating method. Under the synergistic effect of PANI and CNT, the electrocatalytic performance of the modified electrode for Tyr detection was enhanced. At the same time, since the protonation of polyaniline leads to changes in OCP, pH can be detected.
[0022] Furthermore, in step (1) above, the mass concentration of the tannic acid solution is 10-30 mg / mL, preferably 10 mg / mL, 20 mg / mL or 30 mg / mL; the mass concentration of the silver nitrate solution is 10-75 mg / mL, preferably 10 mg / mL, 20 mg / mL, 30 mg / mL and 75 mg / mL; the mixing and stirring time is 20-40 min, preferably 30 min.
[0023] The beneficial effect of adopting the above-mentioned further technical solution is that the present invention utilizes the antibacterial activity of silver nanoparticles and the catechin functional groups of tannic acid to obtain highly efficient antibacterial activity and enhance the adhesion performance of hydrogel.
[0024] Furthermore, in step (2) above, the mass-volume ratio of ammonium persulfate, carbon nanotubes, TA-Ag nanoparticles and water in solution A is 456.4 mg: 6 mg: 30 mg: 1.0 mL.
[0025] The beneficial effect of adopting the above-mentioned further technical solution is that carbon nanotubes can enhance the electrical conductivity of hydrogels.
[0026] Furthermore, in step (2) above, the volume molar concentration of hydrochloric acid in solution B is 5-6 mol / L, preferably 6 mol / L; the mass-volume ratio of 3-aminophenylborate salt, hydrochloric acid, aniline and water is 18.3 mg: 835 μL: 1.5 mmol: 225 μL.
[0027] The beneficial effect of adopting the above-mentioned further technical solution is that this step is an oxidative polymerization process of aniline, 3-aminophenylborate salt is a monomer of aniline, ammonium persulfate is used as an initiator, and hydrochloric acid is used as a reaction dopant.
[0028] Furthermore, in step (2) above, the mass percentage of the polyvinyl alcohol aqueous solution in solution C is 10%-12%, preferably 10%; the volume of the polyvinyl alcohol aqueous solution is 3 mL.
[0029] The beneficial effect of adopting the above-mentioned further technical solution is that polyvinyl alcohol, as a crosslinking agent for the aniline hydrogel reaction, enables aniline to form a hydrogel during the oxidative polymerization process.
[0030] Furthermore, in step (3) above, the volumetric molar concentration of potassium phosphate buffer is 0.1 mol / L, and the pH is 7.0; the mass-volume ratio of agarose to potassium phosphate buffer is 0.4 g: 10 mL; and the temperature for continuous stirring is 150-170 °C, preferably 170 °C.
[0031] The beneficial effect of adopting the above-mentioned further technical solution is that the agarose hydrogel can be loaded with electrostimulation drugs and potassium phosphate buffer solution. The potassium phosphate buffer solution can prevent potential pH changes on the epidermis due to ion accumulation at the sampling points during repeated sensing.
[0032] Furthermore, in step (4) above, the ion-importing electrode includes an Ag cathode and an Ag anode; the diameter of the carbon working electrode is 3 mm.
[0033] The beneficial effect of adopting the above-mentioned further technical solution is that, after energization, a positive charge accumulates at the Ag anode of the ion-importing electrode, thereby repelling the positively charged pilocarpine drug from entering the skin and inducing sweating. The electrochemical sensor can perform in-situ detection of the pH value and Tyr concentration of the generated sweat.
[0034] Furthermore, in step (5) above, the volume of the TA-Ag-PANI-CNT hydrogel is 1 μL; the mass percentage of the pilocarpine solution is 2%-3%, preferably 3%; and the holding time is 1-2 h, preferably 1 h.
[0035] The beneficial effect of adopting the above-mentioned further technical solution is that pilocarpine belongs to the cholinergic drug category and has the effect of stimulating the secretion of exocrine glands, thereby causing sweating.
[0036] The present invention also claims the application of a wearable sensor prepared by the above method in detecting pH value and Tyr concentration in human sweat.
[0037] Furthermore, the specific detection method described above is as follows: Before detection, the subject's skin is wiped with isopropanol, and the wearable sensor is attached to the subject's forearm with medical double-sided tape; in the actual measurement, firstly, a constant voltage of 2.0V is applied for 20 minutes between the cathode and anode electrodes of the ion-importing electrode using a CHI660E electrochemical workstation to induce and collect sweat; then, the open circuit potential (OCP) is recorded for 60 seconds, and the pH value is determined using a calibration chart obtained from the in vitro experiment; next, based on the measured pH value, the Tyr concentration is calculated from the differential pulse voltammetry (DPV) measurement using a calibration chart at a specific pH value; finally, the Tyr and pH levels of the collected sweat are detected using a standard enzyme-linked immunosorbent assay (ELISA) method and a pH meter.
[0038] As can be seen from the above technical solution, compared with the prior art, the beneficial effects of the present invention are as follows:
[0039] 1. This invention integrates a wearable sensor system that combines a composite hydrogel electrochemical sensor with an iontophoresis electrode for direct sweat stimulation. The composite hydrogel consists of a polyaniline hydrogel modified with tannic acid-chelated silver nanoparticles (TA-AgNPs) and carbon nanotubes (CNTs). This PANI hydrogel, with its large specific surface area, exhibits high catalytic activity for pH and Tyr concentration detection. To better facilitate application on the skin surface, TA-AgNPs are introduced to ensure the hydrogel's high antibacterial activity; the addition of CNTs improves the hydrogel's conductivity, catalytic performance, and mechanical properties. With the aid of pH sensing results, the Tyr concentration in various sweat samples is corrected to ensure reliable accuracy. This method will have a profound impact on the design of wearable sweat sensors and personalized medicine.
[0040] 2. This invention designs a wearable sensor that integrates two important functions into a single wearable sensor patch: an iontophoresis system to stimulate sweat production and an electrochemical sensor based on TA-Ag-CNT-PANI hydrogel. Sweat production is induced by fabricating an iontophoresis electrode, and the electrochemical sensor non-invasively detects pH and Tyr concentration. To better suit human skin applications, a TA-Ag-CNT-PANI hydrogel with antibacterial properties, good mechanical properties, and structural stability was designed. The sensor based on this hydrogel can simultaneously detect pH and Tyr levels in human sweat, and shows good correlation with the results from commercial pH meters and ELISA kits. More importantly, with pH calibration, reliable and accurate detection of Tyr levels in human sweat can be achieved. Ultimately, this research will contribute to the development of stable wearable sensors for precise sweat detection. Attached Figure Description
[0041] Figure 1 This is a schematic diagram of the structure of a wearable sensor (IP electrodes and a three-electrode sensing system);
[0042] Figure 2 This is a schematic diagram of a screen-printed sensor array.
[0043] Figure 3 This is a schematic diagram of the operation of the IP electrode;
[0044] Figure 4 This is a comparison chart of the pH value detection results of six sweat samples by a wearable sensor and a traditional pH meter in Example 2;
[0045] Figure 5 Linear calibration plot for Tyr concentration detection by ELISA method;
[0046] Figure 6This is a comparison chart showing the results of Tyr concentration detection in six sweat samples using the wearable sensor from Example 2 (before and after calibration) and the ELISA method. Detailed Implementation
[0047] 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.
[0048] Example 1
[0049] The method for fabricating wearable sensors specifically includes the following steps:
[0050] (1) Preparation of TA-Ag nanoparticles
[0051] First, tannic acid powder was dissolved in water to obtain a tannic acid solution with a mass concentration of 10 g / mL; then, silver nitrate powder was dissolved in water to obtain a silver nitrate solution with a mass concentration of 10 mg / mL; the tannic acid solution and the silver nitrate solution were then mixed and stirred for 20 min; finally, the mixture was centrifuged and washed to obtain TA-Ag nanoparticles.
[0052] (2) Preparation of TA-Ag-CNT-PANI hydrogel
[0053] First, 456.4 mg of ammonium persulfate, 46 mg of carbon nanotubes, and 30 mg of TA-Ag nanoparticles were dissolved in 1.0 mL of water to obtain solution A. Then, 18.3 mg of 3-aminophenylborate acid salt was dissolved in 835 μL of hydrochloric acid with a volume mol / L concentration, followed by the addition of 1.5 mmol of aniline and 225 μL of water to obtain solution B. Next, solution B was added dropwise to 3 mL of a 10% (w / w) polyvinyl alcohol aqueous solution under magnetic stirring to obtain solution C. Finally, solution A was added to solution C and stirred rapidly to obtain TA-Ag-CNT-PANI hydrogel, which was then ready for use.
[0054] (3) Preparation of agarose hydrogel
[0055] First, dissolve 0.4g of agarose in 10mL of potassium phosphate buffer with a volume molar concentration of 0.1mol / L and a pH of 7.0, and stir continuously at 150℃ until completely dissolved. Then pour it onto a mold and cool to room temperature to obtain agarose hydrogel for later use.
[0056] (4) Construction of wearable electrode array
[0057] A wearable electrode array is composed of an ion-introduction electrode including an Ag cathode and an Ag anode, and an electrochemical sensor including an Ag / AgCl reference electrode, a carbon counter electrode, and a carbon working electrode with a diameter of 3 mm.
[0058] (5) Modification of wearable electrode arrays
[0059] First, 1 μL LTA-Ag-PANI-CNT hydrogel was drop-coated onto the carbon working electrode; then, before electrical stimulation, the agarose hydrogel was cut into the same size as the ion-importing electrode and covered onto the ion-importing electrode; finally, a 3% (w / w) pilocarpine solution was drop-into the agarose hydrogel and kept for 1 hour to obtain the wearable sensor.
[0060] Example 2
[0061] The method for fabricating wearable sensors specifically includes the following steps:
[0062] (1) Preparation of TA-Ag nanoparticles
[0063] First, tannic acid powder was dissolved in water to obtain a tannic acid solution with a mass concentration of 20 mg / mL; then, silver nitrate powder was dissolved in water to obtain a silver nitrate solution with a mass concentration of 30 mg / mL; the tannic acid solution and the silver nitrate solution were then mixed and stirred for 30 min; finally, the mixture was centrifuged and washed to obtain TA-Ag nanoparticles.
[0064] (2) Preparation of TA-Ag-CNT-PANI hydrogel
[0065] First, 456.4 mg of ammonium persulfate, 46 mg of carbon nanotubes, and 30 mg of TA-Ag nanoparticles were dissolved in 1.0 mL of water to obtain solution A. Then, 18.3 mg of 3-aminophenylborate acid salt was dissolved in 835 μL of hydrochloric acid with a volume molar concentration of 6 mol / L, followed by the addition of 1.5 mmol of aniline and 225 μL of water to obtain solution B. Next, solution B was added dropwise to 3 mL of a 10% (w / w) polyvinyl alcohol aqueous solution under magnetic stirring to obtain solution C. Finally, solution A was added to solution C and stirred rapidly to obtain TA-Ag-CNT-PANI hydrogel, which was then ready for use.
[0066] (3) Preparation of agarose hydrogel
[0067] First, dissolve 0.4 g of agarose in 10 mL of potassium phosphate buffer with a volume molar concentration of 0.1 mol / L and a pH of 7.0, and stir continuously at 170 °C until completely dissolved. Then pour it onto a mold and cool to room temperature to obtain agarose hydrogel for later use.
[0068] (4) Construction of wearable electrode array
[0069] A wearable electrode array is composed of an ion-introduction electrode including an Ag cathode and an Ag anode, and an electrochemical sensor including an Ag / AgCl reference electrode, a carbon counter electrode, and a carbon working electrode with a diameter of 3 mm.
[0070] (5) Modification of wearable electrode arrays
[0071] First, 1 μL LTA-Ag-PANI-CNT hydrogel was drop-coated onto the carbon working electrode; then, before electrical stimulation, the agarose hydrogel was cut into the same size as the ion-importing electrode and covered onto the ion-importing electrode; finally, a 3% (w / w) pilocarpine solution was drop-into the agarose hydrogel and kept for 1 hour to obtain the wearable sensor.
[0072] Example 3
[0073] The method for fabricating wearable sensors specifically includes the following steps:
[0074] (1) Preparation of TA-Ag nanoparticles
[0075] First, tannic acid powder was dissolved in water to obtain a tannic acid solution with a mass concentration of 30 mg / mL; then, silver nitrate powder was dissolved in water to obtain a silver nitrate solution with a mass concentration of 75 mg / mL; the tannic acid solution and the silver nitrate solution were then mixed and stirred for 40 min; finally, the mixture was centrifuged and washed to obtain TA-Ag nanoparticles.
[0076] (2) Preparation of TA-Ag-CNT-PANI hydrogel
[0077] First, 456.4 mg of ammonium persulfate, 46 mg of carbon nanotubes, and 30 mg of TA-Ag nanoparticles were dissolved in 1.0 mL of water to obtain solution A. Then, 18.3 mg of 3-aminophenylborate acid salt was dissolved in 835 μL of hydrochloric acid with a volume molar concentration of 6 mol / L, followed by the addition of 1.5 mmol of aniline and 225 μL of water to obtain solution B. Next, solution B was added dropwise to 3 mL of a 12% (w / w) polyvinyl alcohol aqueous solution under magnetic stirring to obtain solution C. Finally, solution A was added to solution C and stirred rapidly to obtain TA-Ag-CNT-PANI hydrogel, which was then ready for use.
[0078] (3) Preparation of agarose hydrogel
[0079] First, dissolve 0.4 g of agarose in 10 mL of potassium phosphate buffer with a volume molar concentration of 0.1 mol / L and a pH of 7.0, and stir continuously at 170 °C until completely dissolved. Then pour it onto a mold and cool to room temperature to obtain agarose hydrogel for later use.
[0080] (4) Construction of wearable electrode array
[0081] A wearable electrode array is composed of an ion-introduction electrode including an Ag cathode and an Ag anode, and an electrochemical sensor including an Ag / AgCl reference electrode, a carbon counter electrode, and a carbon working electrode with a diameter of 3 mm.
[0082] (5) Modification of wearable electrode arrays
[0083] First, 1 μL LTA-Ag-PANI-CNT hydrogel was drop-coated onto the carbon working electrode; then, before electrical stimulation, the agarose hydrogel was cut into the same size as the ion-importing electrode and covered onto the ion-importing electrode; finally, a 3% (w / w) pilocarpine solution was drop-into the agarose hydrogel and kept for 2 hours to obtain the wearable sensor.
[0084] Performance testing
[0085] First, human sweat samples were collected from six volunteers. The pH value of the sweat was measured using the wearable sensor (electrochemical sensor) prepared in Example 2 and a traditional pH meter, respectively. The results are as follows: Figure 4 As shown. By Figure 4 It can be seen that the pH values of sweat samples measured by the wearable sensor and the traditional pH meter in Example 2 are close. Clearly, pH values vary from person to person.
[0086] Meanwhile, Tyr levels in sweat samples were measured using a commercial ELISA kit, and the results were as follows: Figure 5 As shown.
[0087] Will Figure 5 For reference, sensor performance was tested separately for sensors with and without pH calibration, and the results are as follows: Figure 6 As shown. By Figure 6 It can be seen that before pH calibration, the Tyr concentration detected by the wearable sensor in Example 2 was lower or higher than the ELISA results in the range of 4.0-8.0. After calibration (using the correct calibration curve at the accurate pH value), the Tyr concentration detected by the wearable sensor in Example 2 was closer to the ELISA results. Therefore, calibrating data at different pH values (measured by the same sensor) can effectively improve the accuracy of wearable sensors for Tyr detection.
[0088] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A method for fabricating a wearable sensor, characterized in that, Specifically, the following steps are included: (1) Preparation of TA-Ag nanoparticles First, tannic acid powder was dissolved in water to obtain a tannic acid solution; then, silver nitrate powder was dissolved in water to obtain a silver nitrate solution; the tannic acid solution and the silver nitrate solution were then mixed and stirred; finally, the mixture was centrifuged and washed to obtain TA-Ag nanoparticles. The tannic acid solution has a mass concentration of 10-30 mg / mL; the silver nitrate solution has a mass concentration of 10-75 mg / mL. (2) Preparation of TA-Ag-CNT-PANI hydrogel First, ammonium persulfate, carbon nanotubes, and TA-Ag nanoparticles were dissolved in water to obtain solution A; then, 3-aminophenylborate acid salt was dissolved in hydrochloric acid, followed by the addition of aniline and water to obtain solution B; solution B was then added dropwise to a polyvinyl alcohol aqueous solution under magnetic stirring to obtain solution C; finally, solution A was added to solution C and stirred rapidly to obtain TA-Ag-CNT-PANI hydrogel, which was then set aside for later use. In solution A, the mass-to-volume ratio of ammonium persulfate, carbon nanotubes, TA-Ag nanoparticles, and water is 456.4 mg: 6 mg: 30 mg: 1.0 mL; In solution B, the volumetric molar concentration of the hydrochloric acid is 5-6 mol / L; the mass-volume ratio of the 3-aminophenylborate salt, hydrochloric acid, aniline, and water is 18.3 mg: 835 μL: 1.5 mmol: 225 μL. In solution C, the mass percentage of the polyvinyl alcohol aqueous solution is 10%-12%, and the volume is 3 mL; (3) Preparation of agarose hydrogel First, dissolve agarose in potassium phosphate buffer and stir continuously until completely dissolved. Then pour it onto a mold and cool to room temperature to obtain agarose hydrogel for later use. (4) Construction of wearable electrode array An ion-importing electrode and an electrochemical sensor are combined to form a wearable electrode array; wherein, the electrochemical sensor has a three-electrode system, including an Ag / AgCl reference electrode, a carbon counter electrode, and a carbon working electrode; (5) Modification of wearable electrode arrays First, TA-Ag-PANI-CNT hydrogel is drop-coated onto the carbon working electrode; then, before electrical stimulation, agarose hydrogel is cut into the same size as the ion-importing electrode and covered onto the ion-importing electrode; finally, pilocarpine solution is drop-into the agarose hydrogel and held in place, thus obtaining the wearable sensor.
2. The method for fabricating a wearable sensor according to claim 1, characterized in that, In step (1), the mixing and stirring time is 20-40 minutes.
3. The method for fabricating a wearable sensor according to claim 1, characterized in that, In step (3), the volumetric molar concentration of the potassium phosphate buffer is 0.1 mol / L, and the pH is 7.0; the mass-volume ratio of the agarose to the potassium phosphate buffer is 0.4 g: 10 mL; and the temperature for continuous stirring is 150-170℃.
4. The method for fabricating a wearable sensor according to claim 1, characterized in that, In step (4), the ion-importing electrode includes an Ag cathode and an Ag anode.
5. The method for fabricating a wearable sensor according to claim 1, characterized in that, In step (4), the diameter of the carbon working electrode is 3 mm.
6. The method for fabricating a wearable sensor according to claim 1, characterized in that, In step (5), the volume of the TA-Ag-PANI-CNT hydrogel is 1 μL; the mass percentage of the pilocarpine solution is 2%-3%; and the holding time is 1-2 h.