Gel epidermal electrode formed by in-situ autocatalysis and electrophysiological signal monitoring system and device

Abstract

The invention discloses an in-situ autocatalytic forming gel epidermal electrode, an electrophysiological signal monitoring system and an electrophysiological signal monitoring device. The gel precursor includes a supramolecular solvent selected from a specific monomer, a metal ion catalyst, an initiator, a cross-linking agent, and a hydrogen bond acceptor and a hydrogen bond donor. The gel precursor provided by the invention can perform autocatalysis to initiate crosslinking to form a sensing medium with an interlocking structure, and meanwhile, can form a stable interface structure with the skin to ensure that the gel precursor is tightly attached to epidermal tissues, and motion artifacts caused by relative displacement in a motion process are reduced to the greatest extent. According to the invention, the electrode is formed by gelling the gel precursor on the skin surface, and the electrode has low interface impedance so as to ensure high signal fidelity, excellent mechanical stability, dynamic adhesion, stable electrochemical performance and biocompatibility, and can be reliably used for a long time. The method can be widely applied to wearable equipment, electronic skin, medical equipment and the like.

Description

Technical Field

[0001] This invention relates to the field of biosensor materials technology, specifically to an in-situ self-catalytically formed gel epidermal electrode, an electrophysiological signal monitoring system and device. Background Technology

[0002] With the development of wearable health monitoring devices and smart medical technologies, the demand for real-time, long-term dynamic monitoring of human bioelectrical signals is increasing. It is worth noting that the reliability, stability, comfort, and personalization of these devices are also crucial for monitoring human bioelectrical signals due to interference from human movement, sweat, and other physiological factors. In recent years, through the design and optimization of electrode materials, some materials with excellent conductivity and tunable doping properties have been developed, which is of great significance in overcoming the limitations of traditional electrodes in physiological signal detection. However, electrodes made from these materials are still susceptible to changes in contact impedance caused by sweat, resulting in poor signal quality. Furthermore, by designing electrode structures and enhancing the electrode structure through engineering architecture and microneedle arrays, significant advantages have been shown in real-time monitoring and long-term wear scenarios. Despite the many advantages of microneedle structures, several challenges remain, including complex manufacturing processes, potential skin irritation, and infection risks, which can affect user comfort. Furthermore, due to reduced interfacial impedance and minimized environmental noise and motion artifacts, most electrode materials can achieve stable and reliable monitoring signals under static conditions by improving flexibility, skin adhesion, conductivity, and self-adhesion. However, these electrolytic materials still cannot meet the requirements for real-time monitoring of electrophysiological signals during complex dynamic movements. Therefore, establishing a tissue-electrode-device connection loop and constructing an excellent bioelectronic interface to obtain stable and high-quality electrophysiological (EP) signals for real-time monitoring of electrophysiological signals during complex dynamic movements remains a significant challenge. Summary of the Invention

[0003] Therefore, it is necessary to provide a gel precursor that enables the in-situ formed epidermal electrodes to have excellent conductivity, low interfacial impedance, high tissue adhesion, excellent epidermal conformability, mechanical stability and tissue biocompatibility, thereby ensuring excellent electrical signal acquisition and monitoring in static and various dynamic states.

[0004] In a first aspect, this application provides a gel precursor, the composition of which includes a monomer, a metal ion catalyst, an initiator, a crosslinking agent, and a supramolecular solvent; the monomer includes one or more of acrylamide, methacrylamide, N-ethylacrylamide, N-hydroxymethylacrylamide, N,N'-dimethylacrylamide, N-isopropylacrylamide, [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide, 3-[(3-acrylamidopropyl)dimethylammonium]propane-1-sulfonate, N-(3-aminopropyl)methacrylamide hydrochloride, and 2-acrylamido-2-methylpropanesulfonic acid; the supramolecular solvent includes a hydrogen bond acceptor and a hydrogen bond donor.

[0005] In some embodiments, the gel precursor satisfies at least one of the following characteristics (1) to (8):

[0006] (1) The monomer comprises two or more of the following: acrylamide, methacrylamide, N-ethylacrylamide, N-hydroxymethylacrylamide, N,N'-dimethylacrylamide, N-isopropylacrylamide, [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide, 3-[(3-acrylamidopropyl)dimethylammonium]propane-1-sulfonate, N-(3-aminopropyl)methacrylamide hydrochloride and 2-acrylamido-2-methylpropanesulfonic acid;

[0007] (2) The metal ion catalyst includes a soluble salt of a metal;

[0008] Optionally, the soluble salt of the metal includes one or more of the metal chloride and the metal nitrate;

[0009] Optionally, the metal includes one or more of silver, iron, nickel, and cobalt;

[0010] Further optionally, the soluble salt of the metal includes one or more of silver nitrate, ferric chloride, nickel chloride, and cobalt chloride;

[0011] (3) The initiator includes persulfate initiators;

[0012] Further optionally, the persulfate initiator includes one or more of potassium persulfate, sodium persulfate, and ammonium persulfate;

[0013] (4) The crosslinking agent includes one or more of N,N'-methylenediacrylamide, polyethylene glycol diacrylate and methacrylamide gelatin;

[0014] (5) The hydrogen bond acceptor includes one or more of L-carnitine, betaine, citric acid (CAS No.: 77-92-9) and malic acid;

[0015] (6) The hydrogen bond donor includes one or more of sorbitol, glycerol, glucose, xylitol and water;

[0016] (7) The molar ratio of the hydrogen bond acceptor to the hydrogen bond donor is (1-3):(1-3);

[0017] (8) The composition of the gel precursor by mass parts includes 180-220 parts of monomer, 5-20 parts of metal ion catalyst, 1-10 parts of initiator, 0.01-0.5 parts of crosslinking agent and 250-500 parts of supramolecular solvent.

[0018] In some embodiments, the conductive agent also satisfies the characteristics shown in (1) and / or (2) below:

[0019] The gel precursor also satisfies the following characteristics as shown in (1) and / or (2):

[0020] (1) The gel precursor also contains a conductive agent;

[0021] Optionally, the conductive agent includes one or more of metal salts, metal nanomaterials, conductive polymers, conductive carbon materials, and polyelectrolyte monomers;

[0022] Further optionally, the metal salt includes one or more of potassium chloride, sodium chloride, calcium chloride, copper chloride, and ferric chloride;

[0023] Further optionally, the metal nanomaterial includes one or more of silver nanoparticles, silver nanowires, conductive silver sheets, copper nanowires, and gold nanoparticles;

[0024] Further optionally, the conductive polymer includes one or more of polyaniline, polypyrrole, poly3,4-ethylenedioxythiophene, and conductive polymers containing dopants;

[0025] Further optionally, the dopant includes one or more selected from poly(styrene sulfonic acid), hydrochloric acid, sulfuric acid, and citric acid;

[0026] Further optionally, the conductive carbon material includes one or more of conductive carbon black, conductive carbon nanotubes, and conductive graphene;

[0027] Further optionally, the polyelectrolyte monomer comprises one or more of N-(3-aminopropyl)methacrylamide hydrochloride, N,N,N-trimethyl-3-(2-methylallylamino)-1-propanediamine chloride, sodium 2-acrylamido-2-methylpropanesulfonate, sodium acrylate, and 3-[(3-acrylamidopropyl)dimethylammonium]propane-1-sulfonate;

[0028] (2) The gel precursor contains 0.01-20 parts of conductive agent by mass.

[0029] Secondly, this application also provides a skin electrode, which is formed in situ by autocatalysis using the gel precursor provided in the first aspect.

[0030] In some embodiments, the thickness of the epidermal electrode is 0.1 mm to 2 mm.

[0031] Thirdly, this application also provides a method for preparing an epidermal electrode, comprising the following steps:

[0032] Prepare supramolecular solvents;

[0033] Monomers are added to the supramolecular solution and mixed to form a precursor solution;

[0034] A metal ion catalyst, an initiator, and a crosslinking agent are added to the precursor solution to form a gel precursor;

[0035] The gel precursor is coated onto the surface of the skin for in-situ gelation to form an epidermal electrode.

[0036] The monomers include one or more of acrylamide, methacrylamide, N-ethylacrylamide, N-hydroxymethylacrylamide, N,N'-dimethylacrylamide, N-isopropylacrylamide, [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide, 3-[(3-acrylamidopropyl)dimethylammonium]propane-1-sulfonate, N-(3-aminopropyl)methacrylamide hydrochloride, and 2-acrylamido-2-methylpropanesulfonic acid;

[0037] The supramolecular solvent includes hydrogen bond acceptors and hydrogen bond donors;

[0038] Optionally, the coating method includes one or more of spin coating, spray coating and injection coating.

[0039] Fourthly, this application provides an electrophysiological signal sensor, the sensor comprising the epidermal electrode provided in the second aspect;

[0040] Optionally, the electrophysiological signal sensor may take the form of one or more of epidermal in-situ patterning, patches, and fabrics.

[0041] Fifthly, this application also provides a monitoring system comprising at least one electrophysiological signal sensor provided in the fourth aspect.

[0042] Optionally, the monitoring system further includes one or more of an accelerometer, a temperature sensor, a Bluetooth component, a signal conditioning component, and a signal processing component; and / or, the electrophysiological signal sensor includes at least three, forming a distributed sensor array.

[0043] Sixthly, this application also provides a monitoring device, which includes the electrophysiological signal sensor provided in the fourth aspect, or the monitoring system provided in the fifth aspect;

[0044] Optionally, the monitoring device includes one or more of wearable devices, electronic skin, and medical devices.

[0045] Compared with traditional technologies, the beneficial effects of the technical solution in this application include:

[0046] This application prepares a gel precursor by selecting specific monomers, metal ion catalysts, initiators, crosslinking agents, and supramolecular solvents including hydrogen bond acceptors and hydrogen bond donors. The gel precursor can undergo autocatalytic crosslinking to form an interlocking sensing medium on the skin surface. Simultaneously, it forms a stable bio-electronic interface with the skin, ensuring close adhesion to the epidermal tissue and minimizing motion artifacts caused by relative displacement during movement. This application uses the gel precursor to form an electrode with signal transmission and acquisition capabilities on the skin surface. It exhibits excellent transmission and acquisition effects in both static and dynamic environments, with low interfacial impedance to ensure high signal fidelity; excellent mechanical stability; strong dynamic adhesion; stable electrochemical performance for reliable long-term use; and excellent biocompatibility. It can be widely used in wearable devices, electronic skin, and medical devices. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the electrode structure.

[0048] Figure 2 An EGIE electrode that conforms to human skin.

[0049] Figure 3 Photographs showing the adhesion of button electrodes to different gel interfaces.

[0050] Figure 4 Stress-strain curves for EGIE electrodes with different MAEDS: AMPS: AAm molar ratios.

[0051] Figure 5 Elastic modulus and fracture strain of EGIE electrodes with different MAEDS: AMPS: AAm molar ratios.

[0052] Figure 6Adhesion forces of EGIE with different MAEDS:AMPS:AAm molar ratios.

[0053] Figure 7 The interfacial adhesion between different electrodes and the skin.

[0054] Figure 8 Photographs of EGIE electrodes on the skin over 7 days and their biocompatibility.

[0055] Figure 9 The resistance of EGIE with different MAEDS:AMPS:AAm molar ratios.

[0056] Figure 10 The ionic conductivity of EGIE with different MAEDS:AMPS:AAm molar ratios.

[0057] Figure 11 This refers to the interfacial impedance between the electrodes and the skin for different electrodes.

[0058] Figure 12 The ECG signals (a) and T / R values ​​(b) of the EGIE electrode and Ag / AgCl electrode under static conditions are shown.

[0059] Figure 13 The sEMG signal SNR values ​​(a), signal baseline, and RMS values ​​(b) of the EGIE electrode and Ag / AgCl electrode under static conditions are shown.

[0060] Figure 14 ECG signal (a) and T / R value (b) of EGIE over 3 days.

[0061] Figure 15 The sEMG signal, RMS value, and SNR value were recorded by the EGIE and Ag / AgCl electrodes during a 10-day long-term test.

[0062] Figure 16 This is a schematic diagram illustrating the mechanism of EGIE electrodes in the dynamic physiological signal acquisition process.

[0063] Figure 17 Electrocardiogram (ECG) signals and heart rate (HR) recorded by EGIE electrodes during physical activities such as walking, squatting, and jogging.

[0064] Figure 18 The interface state of the EGIE electrode under different exercise conditions (a) and the recorded electrocardiogram signal and heart rate (b) are shown from top to bottom: (i) standing, (ii) jogging and sweating, and (iii) resting for 60 minutes after running.

[0065] Figure 19 Electromyographic signals recorded by EGIE electrodes during leg extension movements.

[0066] Figure 20 Electromyographic signals recorded by EGIE electrodes at different running speeds.

[0067] Figure 21 It is an ECG-Wear that incorporates distributed EGIE electrodes, sensors, and Bluetooth components on a fabric carrier.

[0068] Figure 22 To perform multi-parameter physiological monitoring under various human movements, including (i) standing, (ii) exercising on an elliptical machine, (iii) chest compressions, (iv) sitting up, (v) climbing stairs, and (vi) running. From top to bottom: acceleration, electrocardiogram, temperature, respiratory rate, and heart rate (HR).

[0069] Figure 23 Long-term testing of the ECG clothing system was conducted (i) on day 1 from 11:30 p.m. to 11:30 a.m., and (ii) on day 2 from 11:30 a.m. to 11:30 p.m. Detailed Implementation

[0070] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0071] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0072] As used herein, "optional," "optional," and "optional" refer to either "with" or "without" parallel options. If multiple "optional" entries appear in a technical solution, each "optional" entry is independent unless otherwise specified and there are no contradictions or mutual constraints. The term "and / or" as used herein includes any and all combinations of one or more related listed items. Unless otherwise specified, "multiple," "multiple," etc., as used herein refer to a quantity greater than 2 or equal to 2; for example, "one or more" indicates one, two, or more than two. In open-ended technical features or solutions described herein using words such as "containing," "including," and "comprising," unless otherwise specified, additional members beyond the listed members are not excluded. This can be considered as providing both a closed-ended feature or solution consisting of the listed members and an open-ended feature or solution that includes additional members beyond the listed members.

[0073] In this application, the terms "first aspect," "second aspect," "third aspect," "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," "fourth," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0074] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0075] Due to interference from human movement, sweat, and other physiological factors, devices for real-time, long-term dynamic monitoring of bioelectrical signals in human health require superior reliability, stability, comfort, and personalization. Therefore, developing highly compatible, efficient, and comfortable wearable health monitoring devices to obtain reliable bioelectrical signals is crucial, and this is one of the most challenging problems facing modern science and technology. This application aims to construct a material capable of forming excellent bioelectronic interfaces, while also forming electrode materials with excellent conductivity, low interfacial impedance, high tissue adhesion, excellent epidermal fit, mechanical stability, and tissue biocompatibility. This material can be used in flexible epidermal biosensors to achieve high-precision electrophysiological monitoring.

[0076] In a first aspect, this application provides a gel precursor, the composition of which includes a monomer, a metal ion catalyst, an initiator, a crosslinking agent, and a supramolecular solvent; the monomer includes one or more of acrylamide, methacrylamide, N-ethylacrylamide, N-hydroxymethylacrylamide, N,N'-dimethylacrylamide, N-isopropylacrylamide, [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide, 3-[(3-acrylamidopropyl)dimethylammonium]propane-1-sulfonate, N-(3-aminopropyl)methacrylamide hydrochloride, and 2-acrylamido-2-methylpropanesulfonic acid; the supramolecular solvent includes a hydrogen bond acceptor and a hydrogen bond donor.

[0077] The gel precursor of this application possesses the characteristic of self-catalytically initiating cross-linking reactions. Through the catalytic initiation of cross-linking of monomers using metal particle catalysts, initiators, cross-linking agents, and supramolecular solvents, it can form a gel in situ and create an excellent sensing medium that can serve as an electrode for signal transmission. The specific monomers and supramolecular solvents selected in the gel precursor can form an "interlocking" special structure, creating a stable interface structure with extremely low interfacial impedance on the skin surface. This ensures that the sensing medium formed by the gel precursor adheres closely to the epidermal tissue, enabling stable signal transmission in both static and dynamic states. In particular, it minimizes motion artifacts caused by relative displacement during movement and has low interfacial impedance to ensure high signal fidelity. It also exhibits excellent mechanical stability, dynamic adhesion, stable electrochemical performance, and biocompatibility, enabling reliable long-term use.

[0078] In some embodiments, the monomer comprises two or more of acrylamide, methacrylamide, N-ethylacrylamide, N-hydroxymethylacrylamide, N,N'-dimethylacrylamide, N-isopropylacrylamide, [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide, 3-[(3-acrylamidopropyl)dimethylammonium]propane-1-sulfonate, N-(3-aminopropyl)methacrylamide hydrochloride, and 2-acrylamido-2-methylpropanesulfonic acid.

[0079] In some embodiments, the molar ratio of [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide to 2-acrylamido-2-methylpropanesulfonic acid in the monomer is (1-2):(1-2), including but not limited to 1:1, 1:1.5, 1:2, 2:1, 2:1.5, 2:1.8, 2:2 or any of the foregoing ranges and values ​​within those ranges.

[0080] In some embodiments, the molar ratio of [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide, 2-acrylamido-2-methylpropanesulfonic acid, and acrylamide in the monomer is (1-2):(1-2):(1-6), including but not limited to 1:1:1, 1:2:1, 1:1:2, 1:1:3, 1:1:4, 1:1:5, 1:1:6, 1:2:3, 1:2:4, 1:2:5, 1:2:6, 2:1:1, 2:2:1, 2:2:3, 2:2:5, 2:2:5.8, 2:2:6, or any of the foregoing ranges and values ​​within those ranges.

[0081] The monomer used in this application can crosslink under the combined action of metal ion catalysts, crosslinking agents, initiators and supramolecular solvents to form an "interlocked" structure, which has excellent adhesion, signal transmission and stability.

[0082] In some embodiments, the metal ion catalyst comprises a soluble salt of a metal.

[0083] In some embodiments, the soluble salt of the metal includes one or more of the metal chloride and the metal nitrate.

[0084] In some embodiments, the metal includes one or more of silver, iron, nickel, and cobalt.

[0085] As a non-limiting example, the soluble salt of the metal includes one or more of silver nitrate, ferric chloride, nickel chloride, and cobalt chloride. The ferric chloride includes ferric chloride hexahydrate.

[0086] This application achieves the autocatalytic effect of the gel precursor by adding metal ions, thereby enabling the gel precursor to gel in situ on the skin surface and form a signal sensing medium.

[0087] In some embodiments, the initiator includes a persulfate initiator.

[0088] In some embodiments, the persulfate initiator includes one or more of potassium persulfate, sodium persulfate, and ammonium persulfate.

[0089] In some embodiments, the crosslinking agent includes one or more of N,N'-methylenediacrylamide, polyethylene glycol diacrylate, and methacrylamide gelatin.

[0090] In some embodiments, the hydrogen bond acceptor includes one or more of L-carnitine, betaine, citric acid, and malic acid.

[0091] In some embodiments, the hydrogen bond donor includes one or more of sorbitol, glycerol, glucose, xylitol, and water.

[0092] In some embodiments, the mass ratio of the hydrogen bond acceptor to the hydrogen bond donor is (1-3):(1-3), including but not limited to 1:1, 1:2, 1:3, 2:1, 2:2, 2:3, 3:1, 3:2, 3:3 or any of the foregoing ranges and values ​​within those ranges.

[0093] In some embodiments, the supramolecular solvent comprises the hydrogen bond acceptor and the hydrogen bond donor dissolved in water.

[0094] In some embodiments, the mass ratio of the total mass of the hydrogen bond acceptor and the hydrogen bond donor to water is (1-6):1, including but not limited to 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, or any combination thereof and values ​​within that range. Furthermore, a mass ratio of the total mass of the hydrogen bond acceptor and the hydrogen bond donor to water of (4-6):1 better achieves the technical effects of this application.

[0095] In some embodiments, the gel precursor comprises, by weight, 180-220 parts of monomer, 5-20 parts of metal ion catalyst, 1-10 parts of initiator, 0.01-0.5 parts of crosslinking agent, and 250-500 parts of supramolecular solvent.

[0096] In some embodiments, the gel precursor comprises, by weight, 190-200 parts of monomer, 10-15 parts of metal ion catalyst, 5-9 parts of initiator, 0.03-0.07 parts of crosslinking agent and 300-400 parts of supramolecular solvent.

[0097] In some embodiments, the gel precursor further comprises a conductive agent.

[0098] In some embodiments, the conductive agent includes one or more of a metal salt, a metal nanomaterial, a conductive polymer, a conductive carbon material, and a polyelectrolyte monomer. As a non-limiting example, the metal salt includes one or more of potassium chloride, sodium chloride, calcium chloride, copper chloride, and ferric chloride. As a non-limiting example, the metal nanomaterial includes one or more of silver nanoparticles, silver nanowires, conductive silver sheets, copper nanowires, and gold nanoparticles. As a non-limiting example, the conductive polymer includes one or more of polyaniline, polypyrrole, poly3,4-ethylenedioxythiophene, and conductive polymers containing dopants. As a non-limiting example, the dopant includes one or more selected from poly(styrene sulfonic acid), hydrochloric acid, sulfuric acid, and citric acid. As a non-limiting example, the conductive carbon material includes one or more of conductive carbon black, conductive carbon nanotubes, and conductive graphene. As a non-limiting example, the polyelectrolyte monomer includes one or more of N-(3-aminopropyl)methacrylamide hydrochloride, N,N,N-trimethyl-3-(2-methylallylamino)-1-propanediamine chloride, sodium 2-acrylamido-2-methylpropanesulfonate, sodium acrylate, and 3-[(3-acrylamidopropyl)dimethylammonium]propane-1-sulfonate.

[0099] In some embodiments, the conductive agent in the gel precursor is 0.01-20 parts by weight, including but not limited to 0.01 parts, 0.05 parts, 0.1 parts, 0.5 parts, 1 part, 2 parts, 3 parts, 5 parts, 8 parts, 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, or any combination thereof and values ​​within that range.

[0100] In some embodiments, the gel precursor comprises, by weight, 180-220 parts of monomer, 5-20 parts of metal ion catalyst, 1-10 parts of initiator, 0.01-0.5 parts of crosslinking agent, 0.01-20 parts of conductive agent, and 250-500 parts of supramolecular solvent.

[0101] In some embodiments, the composition of the gel precursor, by mass parts, includes 190-200 parts of monomer, 10-15 parts of metal ion catalyst, 5-9 parts of initiator, 0.03-0.07 parts of crosslinking agent, 1-5 parts of conductive agent, and 300-400 parts of supramolecular solvent.

[0102] Secondly, this application provides an electrode that is formed in situ by autocatalysis using a gel precursor provided in the first aspect.

[0103] In some embodiments, the thickness of the electrode is 0.1mm-2mm, including but not limited to 0.1mm, 0.5mm, 0.8mm, 1mm, 1.2mm, 1.5mm, 2mm or any combination thereof and values ​​within that range.

[0104] Thirdly, this application provides a method for preparing an electrode, comprising the following steps:

[0105] S10. Prepare supramolecular solvents.

[0106] S20. Add monomers to the supramolecular solution and mix to form a precursor solution.

[0107] S30. Add a metal ion catalyst, an initiator, and a crosslinking agent to the precursor solution to form a gel precursor.

[0108] S40. The gel precursor is coated onto the surface of the skin to form an epidermal electrode through in-situ gelation.

[0109] The composition and content of the monomer, supramolecular solvent, metal ion catalyst, initiator and crosslinking agent are consistent with those in the first aspect.

[0110] In some embodiments, the coating method includes one or more of spin coating, spray coating, and injection coating.

[0111] Fourthly, this application provides an electrophysiological signal sensor, the sensor including the epidermal electrode provided in the second aspect.

[0112] In some embodiments, the sensor may take the form of one or more of epidermal in-situ patterning, patches, and fabrics. Exemplarily, the sensor includes an ionoelectronic tactile sensor.

[0113] Sixthly, this application also provides a monitoring system, which includes at least one sensor provided in the fifth aspect.

[0114] In some embodiments, the monitoring system further includes one or more of an accelerometer, a temperature sensor, a Bluetooth component, a signal conditioning component, and a signal processing component.

[0115] In some embodiments, the sensors include at least three, forming a distributed sensor array.

[0116] In a seventh aspect, this application also provides a monitoring device, which includes the sensor provided in the fifth aspect or the monitoring system provided in the sixth aspect.

[0117] In some embodiments, the monitoring device includes one or more of wearable devices, electronic skin, and medical devices.

[0118] It should be noted that experimental methods in the following embodiments of this application, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All commonly used chemical reagents used in the embodiments are commercially available products, or can be prepared by those skilled in the art using known methods.

[0119] The types and sources of some of the raw materials and reagents involved in the specific embodiments of this application are as follows:

[0120] Acrylamide (CAS No.: 79-06-1), methacrylamide (CAS No.: 79-39-0), N-ethylacrylamide (CAS No.: 5883-17-0), N-hydroxymethylacrylamide (CAS No.: 924-42-5), N,N'-dimethylacrylamide (CAS No.: 2680-03-7), N-isopropylacrylamide (CAS No.: 2210-25-5), [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (CAS No.: 3637-26-1), 2-acrylamido-2-methylpropanesulfonic acid (CAS No.: 15214-89-8).

[0121] [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonic acid propionic)ammonium hydroxide (MAEDS), model M164461-500g, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0122] 2-Acrylamido-2-methylpropanesulfonic acid (AMPS), model A106798-500g, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0123] Acrylamide (AAm), model A108465-500g, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0124] Silver nitrate (CAS No.: 7761-88-8), ferric chloride hexahydrate (CAS No.: 10025-77-1), nickel chloride (CAS No.: 7718-54-9) and cobalt chloride (CAS No.: 7646-79-9).

[0125] Potassium persulfate (CAS No.: 7727-21-1), sodium persulfate (CAS No.: 7775-27-1), ammonium persulfate (CAS No.: 7727-54-0).

[0126] N,N'-methylenediacrylamide (CAS No.: 110-26-9), polyethylene glycol diacrylate (CAS No.: 26570-48-9), methacrylamide gelatin (CAS No.: 2280018-77-9).

[0127] L-carnitine (CAS No.: 541-15-1), betaine (CAS No.: 107-43-7), citric acid (CAS No.: 77-92-9), malic acid (CAS No.: 97-67-6).

[0128] Sorbitol (CAS No.: 50-70-4), glycerol (CAS No.: 56-81-5), glucose (CAS No.: 14431-43-7), xylitol (CAS No.: 87-99-0).

[0129] N-(3-aminopropyl)methacrylamide hydrochloride (CAS No.: 72607-53-5), N,N,N-trimethyl-3-(2-methylallylamino)-1-propanediamine chloride (CAS No.: 51410-72-1), sodium 2-acrylamido-2-methylpropanesulfonate (CAS No.: 5165-97-9), sodium acrylate (CAS No.: 7446-81-3), 3-[(3-acrylamidopropyl)dimethylammonium]propane-1-sulfonate (CAS No.: 80293-60-3).

[0130] Example 1

[0131] The composition of the gel precursor includes: 9 g of monomers (a mixture of at least two of MAEDS, AMPS and AAm), 15.5 g of supramolecular solvent, 0.6 g of silver nitrate (AgNO3), 0.0025 g of N,N'-methylenebisacrylamide (MBAA), 0.25 g of ammonium persulfate (APS), and 19 g of water.

[0132] Table 1: Specific composition (molar ratio) of monomers

[0133]

[0134] Electrode preparation:

[0135] Preparation of CA / Sor supramolecular solvent: Anhydrous citric acid (CA, 116.4 g) and sorbitol (Sor, 144.8 g) were dissolved in 50 g of water and sonicated until completely dissolved to obtain a uniform, transparent and viscous CA / Sor supramolecular solution.

[0136] AMPS and AAm monomers were sonicated in 2 g of deionized water in an ice-water bath. Then, MAEDS was added to the solution and sonicated to dissolve, preparing a monomer mixture. 15.5 g of CA / Sor supramolecular solvent was added to the above monomer mixture and sonicated in an ice-water bath for 10 minutes to ensure uniform dispersion, preparing a precursor solution.

[0137] The solutions of MBAA, APS, and AgNO3 were added to the above precursor solution, stirred thoroughly, and degassed to prepare the gel precursor.

[0138] The above-mentioned gel precursor was applied to the epidermis, and an electrode (EGIE) was formed on the skin within 5 minutes. Electrodes prepared with different monomer compositions were designated as EGIE1, EGIE2, EGIE3, EGIE4, EGIE5, EGIE6, and EGIE7, respectively. The chemical structures of EGIE2 to EGIE7 are attached. Figure 1 As shown.

[0139] Experimental Example 1: Test of Interfacial Adhesion Characteristics of EGIE Electrodes

[0140] Interfacial adhesion tests on EGIE1 to EGIE7 prepared in Example 1 revealed that the seven EGIE electrodes exhibited high skin conformability and excellent interfacial adhesion properties. (See Appendix) Figure 2 As shown, even when the finger is bent at 90° or the skin undergoes complex mechanical deformations such as stretching, compression, and torsion, the gel-skin interface maintains tight contact without noticeable gaps. Furthermore, due to in-situ gelation, EGIE can interact seamlessly with the Ag / AgCl electrode. See Appendix. Figure 3As shown, EGIE can anchor Ag / AgCl electrodes to the skin surface without any additional physical fixation. This dual-interface optimization enables a robust electrical connection throughout the bioelectronic system, successfully circumventing the delamination problem found in traditional metal-hydrogel systems.

[0141] Experimental Example 2: Mechanical Property Testing of EGIE Electrodes

[0142] To ensure reliable and stable physiological signal monitoring under dynamic conditions, the mechanical properties of EGIE1 to EGIE7 prepared in Example 1 were tested in this experiment.

[0143] The testing method was as follows: tensile strain tests on all samples were performed at room temperature using a mechanical testing machine equipped with a 50 N load cell. The reported statistics were derived from at least three tests on the same sample. Unless otherwise specified, standard rectangular specimens (length ≈ 30–40 mm, width ≈ 10 mm) were clamped on a tensile table and stretched at a tensile speed of 50 mm / min.

[0144] The test was conducted using the above testing method, and the test results are shown in the attached figure. Figure 4 and attached Figure 5 As shown in the attached figures, the stress-strain curves of EGIE electrodes prepared with different MAEDS:AMPS:AAm molar ratios differ significantly. By adjusting the AAm concentration, the elastic modulus of EGIE can be adjusted within the range of 8.97 kPa ± 4.1 kPa (1379.52% ± 150.2% fracture strain) to 42.63 kPa ± 4.1 kPa (~900% ± 132% fracture strain), covering the mechanical range of epidermal tissue.

[0145] Experimental Example 3: Peeling Performance Test of EGIE Electrode

[0146] Peel performance tests were conducted on EGIE1 to EGIE7 prepared in Example 1. The effect of different AAM contents on the adhesion strength of EGIE was studied by 180-degree peel test.

[0147] The test method was as follows: the adhesion force of EGIE was measured using a 180° peel test on a mechanical testing machine. Plasma-treated PET film was used as the substrate. One layer of EGIE film was formed on the substrate, and then another layer of plasma-treated substrate was placed on top of it. The sample size was 8-10 mm wide and 60-80 mm long. Load-displacement curve testing was performed using a tensile clamp at a peel test speed of 50 mm / min. The adhesion force was determined by calculating the average peel force (F) and dividing it by the sample width (w).

[0148] The test was conducted using the above testing method, and the test results are shown in the attached figure. Figure 6 and attached Figure 7 As shown in the attached figures, lower AAM content weakens cohesion, while higher AAM content enhances energy dissipation through hydrogen bonding, electrostatic interactions, and hydrophobic association, thereby improving interfacial toughness and the adhesion properties of the EGIE electrode.

[0149] In addition, the interfacial adhesion between the EGIE electrode and the skin was tested (see [link]). Figure 7 Compared to commercially available paste and adhesive gel electrodes, the EGIE electrode prepared in this application exhibits approximately 50% improved adhesion to the skin. The excellent interfacial adhesion of the EGIE electrode is highly advantageous for detecting physiological signals, as it significantly promotes conformity between the EGIE electrode and the epidermis.

[0150] Experimental Example 4: Biocompatibility Test of EGIE Electrode

[0151] Biocompatibility tests were performed on EGIE1 to EGIE7 prepared in Example 1.

[0152] The testing method was as follows: L929 cells were cultured in MEM medium in 24-well plates for imaging and viability determination. L929 cells in the logarithmic growth phase were diluted 1:50 and inoculated with 1×10⁻⁶ cells. 5 Cells were seeded at a density of 100 cells / dish in confocal culture dishes. After incubation at 37°C with 5% CO2 for 24 hours, the cells were washed with PBS to remove serum residue, stained with fluorescent dye (1 mL / dish, 15 min, protected from light), and imaged at 100x magnification after three PBS washes. Cell viability assay (MTT): L929 cells in logarithmic growth phase were seeded at a density of 2 × 10⁻⁶ cells / dish. 4 Cells were seeded in 24-well plates and cultured overnight (5% CO2, 37°C). Treatment groups included a control group (1000 μL / well of complete medium) and an EGIE group (1000 μL / well of electrode extract). After 144 hours of incubation, the culture was replaced with medium containing MTT (0.5 mg / mL, 1000 μL / well, 4 hours). Formazan crystals were dissolved in DMSO (100 μL / well, shaken for 10 min), and the absorbance was measured at 570 nm.

[0153] The test was conducted using the above testing method, and the test results are shown in the attached figure. Figure 8 As shown in the attached figures, the EGIE electrodes also exhibit excellent biocompatibility. When adhered to the epidermis, the EGIE electrodes can adhere firmly without causing redness or allergic reactions for up to seven days. This also indicates that these EGIE electrodes do not interfere with normal skin sweating, as no adverse reactions (such as redness or swelling) were observed on the skin.

[0154] Furthermore, the biocompatibility of the EGIE electrode was rigorously evaluated using in vitro cytotoxicity tests. Confocal microscopy images clearly showed that L929 cells in the EGIE electrode exhibited comparable viability to the control group. MTT assays showed that L929 cell viability remained >99% after 144 hours of exposure to the EGIE electrode, indicating that the EGIE electrode prepared in this application is non-toxic, harmless, and safe for use.

[0155] Experimental Example 5: Electrochemical Performance of the EGIE Electrode

[0156] The electrochemical performance of EGIE1 to EGIE7 prepared in Example 1 was tested. The electrochemical properties of EGIE were systematically characterized by electrochemical impedance spectroscopy (EIS) to evaluate their effectiveness as a bioelectronic interface for high-fidelity signal transmission.

[0157] The test was conducted using the above testing method, and the test results are shown in the attached figure. Figure 9 Appendix Figure 10 and attached Figure 11 As shown in the attached figure, changing the acrylamide (AAm) content can precisely adjust the ionic conductivity of the EGIE electrode (see attached figure). Figure 9 and attached Figure 10 Compared to existing gel electrodes, the EGIE electrode exhibits superior impedance performance (<450±2.8Ω) at physiologically relevant frequencies. Furthermore, the interfacial impedance between different electrodes and skin was tested and compared, and the results showed that the electrode-skin impedance of the EGIE electrode is approximately 25% lower than that of commercially available paste and adhesive gel electrodes (see Appendix). Figure 11 This enables high-fidelity signal acquisition.

[0158] Experimental Example 6: Static Signal Acquisition Test of EGIE Electrode

[0159] Hyperconformal bioelectronic interfaces can significantly improve signal fidelity in dynamic electrophysiological monitoring systems. First, a gel precursor was applied to the epidermis to form an EGIE electrode. Then, a thermoplastic polyurethane (TPU) composite layer covered with a continuous silver film was encapsulated on the surface of the EGIE electrode. A systematic study comparing the EGIE electrode with commercial Ag / AgCl electrodes in static ECG signal acquisition was conducted (see appendix). Figure 12ECG signals acquired using the EGIE electrode show clear P waves, QRS waves, and T wave pulses, comparable to those of commercially available Ag / AgCl electrodes. The relative voltage ratio between the T and R peaks (T / R ratio) is used to assess the quality of the ECG signal. The T / R values ​​of the EGIE electrode are between 0.17±0.02 and 0.3±0.035, meeting the requirements for high-quality ECG signal monitoring. Furthermore, the EGIE electrode exhibits a sensitivity of 0.17±0.02 in static ECG signal acquisition, higher than that of the Ag / AgCl electrode (0.14±0.02), providing a signal with better fidelity.

[0160] Experimental Example 7: Recording of muscle electrical activity using EGIE electrodes

[0161] Surface electromyography (sEMG) records the electrical activity of muscles from the skin surface. Due to its non-invasive nature and ease of operation, it has become a promising technology in the field of human-computer interaction. sEMG signals are recorded using EGIE electrodes and commercially available Ag / AgCl electrodes (see appendix). Figure 13 The signal-to-noise ratio (SNR) of the sEMG signal recorded by the EGIE electrode was 21.83 ± 0.12 dB, higher than that of the Ag / AgCl electrode (9.357 ± 0.07 dB). The baseline potential represents the noise level and can be used as another indicator of signal quality. (Appendix) Figure 13 The baseline root mean square (RMS) potential recorded by the EGIE electrode was 0.016 mV ± 0.0005 mV, lower than that of the Ag / AgCl electrode (0.069 mV ± 0.0005 mV). In summary, the high signal-to-noise ratio and low baseline potential indicate that the sEMG signal recorded by the EGIE electrode is of higher quality.

[0162] Test Example 8: Long-term performance and stability test of EGIE electrodes

[0163] The EGIE electrode underwent long-term testing to evaluate its potential application in wearable devices. During a 3-day ECG monitoring test, the EGIE electrode did not detach or become damaged during daily activities, and ECG signals were acquired throughout the process without baseline drift or peak loss (see Appendix). Figure 14 The sensitivity of daily recorded ECG signals remained at a high level of approximately 0.22 ± 0.0114. Furthermore, we placed EGIE electrodes on the belly of the flexor carpi ulnaris (FCU) muscle in subjects to test long-term electromyographic signals. The results showed that the EGIE electrodes exhibited excellent performance, maintaining a signal-to-noise ratio above 20 dB, while the signal-to-noise ratio of the Ag / AgCl electrodes decreased to 20 dB within 6 hours (see Appendix). Figure 15It is worth noting that the total wearing time in the long-term test exceeded 10 days, but the EGIE electrode did not cause any itching or irritation, indicating that it was comfortable to wear and proving the excellent long-term performance and stability of the EGIE electrode.

[0164] To further verify the advantages of the EGIE electrode of this application compared with traditional electrode materials, different electrode materials were tested, as shown in Table 2.

[0165] Table 2: Performance Tests of Traditional Electrode Materials and EGIE Electrodes

[0166]

[0167] Notes: S: tensile strength, E: elastic modulus, MS: mechanical stability, IC: ionic conductivity, I: 1 KHz impedance, AS: adhesion strength, B: biocompatibility, PEUDAm: poly(ether carbamate diacrylamide), NAGA: N-acryloylglycine, AAm: acrylamide, CC: choline chloride, PAAc: polyacrylic acid, DES: deep eutectic solvent, Gel: gelatin, Gly: glycerol, NH4Cl: ammonium chloride, PVA: polyvinyl alcohol, b-PEI: branched polyethyleneimine, CaCl2: calcium chloride, PA: phytic acid, NIPAM: N-isopropylacrylamide, 2BPyVI-cucurbita[8]urea: 2BPyVI-CB[8], AAc: acrylic acid, BA: butyl acrylate, CABIL: choline acrylate bio-ionic liquid, PEDOT: PSS: poly(3,4-ethylenedioxythiophene) / poly(styrene sulfonate), T FEA: 2,2,2-trifluoroethyl acrylate, P(MMA-r-BA): Poly(methyl methacrylate-isobutyl acrylate), [EMI][TFSI]: 1-Ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, HEAA: N-hydroxyethylacrylamide, IL: Ionic liquid, P(BA-co-MAA): Poly(butyl acrylate-methacrylic acid), [N4111][TFSI]: Butyltrimethylbis(-trifluoromethanesulfonyl)imide, TDE: Triethylene glycol divinyl ether, [VBIM][TFSI]: 1-Vinyl-3-butylimidazolium bis(trifluoromethanesulfonyl)imide, MA: Methyl acrylate, AMT: 1-(3-(acryloyloxy)propyl)-3-methylimidazolium bis(trifluoromethane)sulfonamide. "-" indicates no data. "Y / N" indicates good performance / no such property.

[0168] In summary, compared with traditional iontophores or PMMA-based conductive iontophores (Table 2), the EGIE electrode formed from the gel precursor of this application exhibits better ductility, creep resistance, lower stress relaxation, fatigue resistance under different strain and tensile rates, and an elastic modulus closer to that of human skin. We also tested its biocompatibility by applying it to the skin for up to 7 days, and no allergic reactions or redness were observed. Due to its excellent overall performance, the EGIE electrode achieves high-fidelity electromyography signal acquisition and significantly improves the signal-to-noise ratio (SNR: 21.83 dB ± 0.12 dB) for electromyography monitoring during dynamic movement. Notably, even after continuous wear for 10 days, the EGIE electrode maintains stable performance (SNR > 20 dB), demonstrating its durability.

[0169] Experimental Example 9: Dynamic Motion Monitoring Performance Test of EGIE Electrodes

[0170] Thanks to its superior overall performance, the EGIE electrode achieves unprecedented signal fidelity in dynamic motion monitoring. See the appendix for details. Figure 16 Especially during physical activities such as walking, squatting, and jogging, the EGIE electrode demonstrates a significant advantage in ECG signal detection. During these activities, the P-QRS-T peaks of the EGIE electrode ECG signal are clearly distinguishable, while the T peak of the Ag / AgCl electrode is difficult to distinguish or is severely affected by motion artifacts (see Appendix). Figure 17 ).

[0171] Test Example 10: Test of EGIE Electrode's Resistance to Sweat Interference

[0172] Signal attenuation caused by sweat remains a key limiting factor in wearable electrophysiology, leading to impedance fluctuations, adhesion failure, and amplification of motion artifacts. This study evaluated the sweat-resistant capabilities of the EGIE electrode by detecting ECG signals under different dynamic states, including standing, jogging with sweat, and 60 minutes of rest after running. The study found that the EGIE electrode maintained a stable interface with the epidermis throughout the testing process, while commercial Ag / AgCl electrodes were prone to detachment from the skin under high sweat conditions (see Appendix). Figure 18 It is worth noting that the signals obtained by the EGIE electrode under different conditions are almost unaffected by sweat, and it can still provide clear and stable P-QRS-T waveforms after sweating during exercise, demonstrating better sweat resistance than commercial Ag / AgCl electrodes (see appendix). Figure 18 ).

[0173] Experimental Example 11: Stability Test of EGIE Electrode under Complex Motion

[0174] The EGIE electrode exhibited stable, resolvable, high-fidelity signal output during various complex movements, making it suitable for electromyography (EMG) detection. The EGIE electrode was placed on the vastus lateralis muscle of the right thigh of a volunteer to monitor EMG signals during leg extension movements. The recorded EMG signals showed good stability, and the details of each movement were clearly discernible (see Appendix). Figure 19 Further, EGIE electrodes were placed on the flexor digitorum longus muscle of the volunteer's right calf to monitor electromyographic signals at different running speeds. The electromyographic signals obtained at different running speeds showed very low baseline noise, and the signal gradually increased with increasing running speed while maintaining good stability (see Appendix). Figure 20 The comprehensive performance comparison under various conditions verifies that the EGIE electrode is superior to commercial electrodes in monitoring daily physiological signals, especially in monitoring daily dynamic movements.

[0175] Experimental Example 12: ECG-Wear, a wearable multi-parameter physiological monitoring system containing EGIE electrodes

[0176] Leveraging the superior dynamic monitoring capabilities of EGIE electrodes, we have developed a wearable multi-parameter physiological monitoring system. This system integrates a distributed EGIE array, accelerometer, temperature sensor, and Bluetooth component onto a fabric carrier (referred to as "ECG-Wear"). See Appendix. Figure 21 The distributed EGIE array converts detected physiological signals into electrical signals. These signals are then conditioned, processed, and transmitted before being sent to a microcontroller with computing and serial communication capabilities, enabling the recording of physiological signals during complex daily activities. See Appendix. Figure 22 The demonstration showcased a volunteer wearing an ECG-Wear device, continuously monitoring physiological signals such as triaxial acceleration, heart rate, respiratory rate, electrocardiogram, and body temperature during various activities including standing, elliptical training, chest compressions, sitting up, climbing stairs, and running. Due to the excellent conformability and interfacial adhesion of the EGIE electrodes, the distributed electrode array can firmly adhere to the skin during exercise. The ECG-Wear accurately and continuously monitors all physiological signals throughout the various activities.

[0177] Test Example 13: Long-term performance and stability testing of ECG-Wear

[0178] Long-term measurements were performed using ECG-Wear under everyday living conditions to achieve real-time monitoring and acquisition of high-fidelity physiological parameters. Electrocardiogram signals were continuously monitored in volunteers during two days of daily activities. (See attached image) Figure 23The ECG signals observed during various normal daily activities (e.g., working on a personal computer (PC), walking, sleeping, conducting experiments, and having lunch) from 11:30 PM to 11:30 AM on the first day and from 11:30 AM to 11:30 PM on the second day are displayed. The magnified portion of the figure clearly shows the ECG waveforms. The ECG signal recorded on the second day also shows similar characteristic peaks and excellent stability. It can be concluded that, thanks to the excellent mechanical stability, dynamic skin fit, stable electrical performance, and superior dynamic monitoring capabilities of the EGIE electrodes, ECG-Wear successfully achieved three days of continuous high-fidelity ECG monitoring under daily living conditions with excellent stability.

[0179] The proposed EGIE electrode also shows potential applications in ionoelectronic tactile sensors, enabling human-computer interaction and monitoring other biosignals, including EEG (electroencephalography), EOG (electroophthalmography), and EDA (electrical skin activity).

[0180] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0181] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A gel precursor, characterized in that, The gel precursor comprises monomers, metal ion catalysts, initiators, crosslinking agents, and supramolecular solvents; the monomers include one or more of acrylamide, methacrylamide, N-ethylacrylamide, N-hydroxymethylacrylamide, N,N'-dimethylacrylamide, N-isopropylacrylamide, [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide, 3-[(3-acrylamidopropyl)dimethylammonium]propane-1-sulfonate, N-(3-aminopropyl)methacrylamide hydrochloride, and 2-acrylamido-2-methylpropanesulfonic acid; the supramolecular solvents include hydrogen bond acceptors and hydrogen bond donors.

2. The gel precursor according to claim 1, characterized in that, The gel precursor satisfies at least one of the following characteristics (1) to (8): (1) The monomer comprises two or more of the following: acrylamide, methacrylamide, N-ethylacrylamide, N-hydroxymethylacrylamide, N,N'-dimethylacrylamide, N-isopropylacrylamide, [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide, 3-[(3-acrylamidopropyl)dimethylammonium]propane-1-sulfonate, N-(3-aminopropyl)methacrylamide hydrochloride and 2-acrylamido-2-methylpropanesulfonic acid; (2) The metal ion catalyst includes a soluble salt of a metal; Optionally, the soluble salt of the metal includes one or more of the metal chloride and the metal nitrate; Optionally, the metal includes one or more of silver, iron, nickel, and cobalt; Further optionally, the soluble salt of the metal includes one or more of silver nitrate, ferric chloride, nickel chloride, and cobalt chloride; (3) The initiator includes persulfate initiators; Further optionally, the persulfate initiator includes one or more of potassium persulfate, sodium persulfate, and ammonium persulfate; (4) The crosslinking agent includes one or more of N,N'-methylenediacrylamide, polyethylene glycol diacrylate and methacrylamide gelatin; (5) The hydrogen bond acceptor includes one or more of L-carnitine, betaine, citric acid (CAS No.: 77-92-9) and malic acid; (6) The hydrogen bond donor includes one or more of sorbitol, glycerol, glucose, xylitol and water; (7) The molar ratio of the hydrogen bond acceptor to the hydrogen bond donor is (1-3):(1-3); (8) The composition of the gel precursor by mass parts includes 180-220 parts of monomer, 5-20 parts of metal ion catalyst, 1-10 parts of initiator, 0.01-0.5 parts of crosslinking agent and 250-500 parts of supramolecular solvent.

3. The gel precursor according to claim 2, characterized in that, The gel precursor also satisfies the following characteristics as shown in (1) and / or (2): (1) The gel precursor also contains a conductive agent; Optionally, the conductive agent includes one or more of metal salts, metal nanomaterials, conductive polymers, conductive carbon materials, and polyelectrolyte monomers; Further optionally, the metal salt includes one or more of potassium chloride, sodium chloride, calcium chloride, copper chloride, and ferric chloride; Further optionally, the metal nanomaterial includes one or more of silver nanoparticles, silver nanowires, conductive silver sheets, copper nanowires, and gold nanoparticles; Further optionally, the conductive polymer includes one or more of polyaniline, polypyrrole, poly3,4-ethylenedioxythiophene, and conductive polymers containing dopants; Further optionally, the dopant includes one or more selected from poly(styrene sulfonic acid), hydrochloric acid, sulfuric acid, and citric acid; Further optionally, the conductive carbon material includes one or more of conductive carbon black, conductive carbon nanotubes, and conductive graphene; Further optionally, the polyelectrolyte monomer comprises one or more of N-(3-aminopropyl)methacrylamide hydrochloride, N,N,N-trimethyl-3-(2-methylallylamino)-1-propanediamine chloride, sodium 2-acrylamido-2-methylpropanesulfonate, sodium acrylate, and 3-[(3-acrylamidopropyl)dimethylammonium]propane-1-sulfonate; (2) The gel precursor contains 0.01-20 parts of conductive agent by mass.

4. A skin electrode, characterized in that, The epidermal electrode is formed in situ via autocatalysis using the gel precursor described in any one of claims 1 to 3.

5. The epidermal electrode according to claim 4, characterized in that, The thickness of the electrode is 0.1mm-2mm.

6. A method for preparing a skin electrode, characterized in that, Includes the following steps: Prepare supramolecular solvents; Monomers are added to the supramolecular solution and mixed to form a precursor solution; A metal ion catalyst, an initiator, and a crosslinking agent are added to the precursor solution to form a gel precursor; The gel precursor is coated onto the surface of the skin for in-situ gelation to form an epidermal electrode. The monomers include one or more of acrylamide, methacrylamide, N-ethylacrylamide, N-hydroxymethylacrylamide, N,N'-dimethylacrylamide, N-isopropylacrylamide, [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide, 3-[(3-acrylamidopropyl)dimethylammonium]propane-1-sulfonate, N-(3-aminopropyl)methacrylamide hydrochloride, and 2-acrylamido-2-methylpropanesulfonic acid; The supramolecular solvent includes hydrogen bond acceptors and hydrogen bond donors; Optionally, the coating method includes one or more of spin coating, spray coating and injection coating.

7. An electrophysiological signal sensor, characterized in that, The sensor includes the epidermal electrode as described in claim 4 or 5; Optionally, the electrophysiological signal sensor may take the form of one or more of epidermal in-situ patterning, patches, and fabrics.

8. A monitoring system, characterized in that, The monitoring system includes at least one electrophysiological signal sensor as described in claim 7.

9. The monitoring system according to claim 8, characterized in that, The monitoring system further includes one or more of an accelerometer, a temperature sensor, a Bluetooth component, a signal conditioning component, and a signal processing component; and / or, the electrophysiological signal sensor includes at least three, forming a distributed sensor array.

10. A monitoring device, characterized in that, The monitoring device includes the electrophysiological signal sensor of claim 7, or the monitoring system of claim 8 or 9; Optionally, the monitoring device includes one or more of wearable devices, electronic skin, and medical devices.

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