Chemically detachable hydrogel electrode for physiological electrical measurement and use method thereof

Abstract

The invention provides a chemical detachable hydrogel electrode for physiological electricity measurement and a use method of the chemical detachable hydrogel electrode. The electrode comprises a flexible substrate layer, a flexible packaging layer, a flexible electrode array layer integrated with an inner circuit and one or more electrode points, a hydrogel substrate layer, a detachable hydrogel interface layer, and a high-molecular polymer solution, a metal ion anchoring solution and a metal chelating agent solution which are stored separately, the flexible electrode array layer is arranged in a flexible frame main body jointly constructed by the flexible substrate layer and the flexible packaging layer, the electrode points extend out of a flexible main body frame, the hydrogel substrate layer covers the electrode points, the detachable hydrogel interface layer is detachably arranged on the hydrogel substrate layer, and the flexible packaging layer covers the flexible main body frame. And combination and disassembly with the hydrogel substrate layer are realized through a high-molecular polymer solution, a metal ion anchoring liquid and a metal chelating agent solution. The electrode can be soaked in a chemical solution to realize a detachable hydrogel interface, so that the electrode can be reused, and the risk of cross infection is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of biomedical devices, and particularly to a chemically detachable hydrogel electrode for physiological electrical measurement and a method for using the same. Background Art

[0002] Electrodes for measuring human physiological electricity have important applications in the process of disease treatment and health monitoring. Among them, flexible electrodes, with their good flexibility and better adaptability to the surface of complex biological tissues, can significantly reduce the risk of physical damage to human tissues compared with traditional electrodes when contacting human tissues, thus providing guarantee for the stable acquisition of physiological electrical signals.

[0003] However, the existing flexible electrodes for physiological electrical measurement still have many defects. In terms of materials, the moduli of the electrodes and tissues (such as brain tissues in craniotomy) do not match, and it is easy to cause damage to brain tissues due to the stress generated during long-term monitoring during the monitoring process. In addition, most of the electrodes used in surgical situations or on the surface of wound breaks are disposable products. This is mainly because in the surgical environment or under the conditions of wound breaks, if the existing flexible electrodes are reused, it will bring a great risk of cross-infection, endangering the health and safety of patients. However, disposable flexible electrodes lead to high application costs and increase the medical burden on patients.

[0004] Therefore, a flexible electrode highly compatible with human tissues (such as brain tissues) is needed, which can closely adhere to the tissue surface, ensure the high precision and stability of physiological electrical measurement, realize real-time monitoring and feedback during surgery or at the wound break, and at the same time, through a specific method, realize the reuse of the flexible electrode, reduce costs and reduce the risk of cross-infection. Summary of the Invention

[0005] To solve the problems in the background art, the present invention provides a chemically detachable hydrogel electrode for physiological electrical measurement and a method for using the same. The electrode can measure the electrical signals of tissues, and through soaking in a chemical solution, the combination and disassembly of the detachable hydrogel interface and the hydrogel base layer are realized, thereby realizing the reuse of the electrode, reducing costs and reducing the risk of cross-infection.

[0006] The technical solution of the present invention to solve the above technical problems is as follows:

[0007] In a first aspect, the present invention provides a chemically detachable hydrogel electrode for physiological electrical measurement, comprising a flexible base layer, a flexible encapsulation layer, a flexible electrode array layer integrating an internal circuit and one or more electrode points, a hydrogel base layer, a detachable hydrogel interface layer, and a separately stored polymer solution, a metal ion anchoring solution, and a metal chelating agent solution; the flexible base layer and the flexible encapsulation layer jointly construct a flexible frame body, the flexible electrode array layer is disposed within the flexible frame body, and one or more of the electrode points extend out of the flexible body frame through a window on the flexible encapsulation layer, the hydrogel base layer is disposed on the flexible encapsulation layer and covers the electrode points, the detachable hydrogel interface layer is detachably disposed on the hydrogel base layer for adhesion to human tissue; the solute in the polymer solution is a water-soluble polymer containing carboxyl groups, the metal anchoring solution is an aqueous solution of metal cations / citric acid, and the metal cations are divalent or trivalent; the detachable hydrogel interface layer is combined with and detached from the hydrogel base layer through the polymer solution, the metal ion anchoring solution, and the metal chelating agent solution; during use, an anchoring network of metal cations and polymers is formed on the hydrogel base layer and the detachable hydrogel interface layer with the polymer solution and the metal ion anchoring solution respectively, and the two are anchored by external pressing; after use, the anchoring network of metal cations and polymers is destroyed by soaking in the metal chelating agent solution, and the detachable hydrogel interface layer is detached.

[0008] The principle of the present invention is as follows: during use, since metal chelation bonds are formed between the metal cations in the hydrogel base layer and the detachable hydrogel interface layer and the carboxyl groups in the polymer, the two hydrogel layers are combined together; after use, when soaked in the metal chelating agent solution, as the metal chelating agent solution gradually penetrates into the interface layer between the two hydrogel layers, due to the stronger chelation between the metal cations and the ionic groups in the metal chelating agent solution, the chelation between the metal cations and the polymer is destroyed, thereby destroying the combination between the two hydrogel layers, and the detachable hydrogel interface layer is detached from the electrode.

[0009] The beneficial effects of the present invention: the present invention realizes the combination and detachment of the detachable hydrogel interface layer and the hydrogel base layer through simple chemical solution soaking, can realize the reuse of the electrode by only replacing the detachable hydrogel interface layer, reduces the cost, and reduces the risk of cross-infection.

[0010] According to the above solution, the polymer solution is an aqueous solution of the polymer, and its mass fraction is 5wt%-10wt%;

[0011] The metal ion anchoring solution includes metal cation salts, citric acid and water, and the pH is adjusted to 2.7 - 3.3 using sodium hydroxide. The mass fraction ranges of the metal cation salts and citric acid are 1wt% - 4wt% and 1wt% - 5wt% respectively.

[0012] The metal chelating agent solution includes a metal chelating agent, acetic acid and water. The mass fractions of the metal chelating agent and acetic acid are 5wt% - 15wt% and 0.5wt% - 2wt% respectively.

[0013] According to the above scheme, the high molecular polymer is one or more of polyacrylic acid, hyaluronic acid, sodium alginate, polyaspartic acid and carboxymethyl cellulose; the metal cation is Fe 3+ 、Zr 4+ and Al 3+ one or more of; the metal chelating agent is EDTANa 4 .

[0014] In some specific embodiments of the present invention, the high molecular polymer is polyacrylic acid, the high - valence metal cation is Fe 3+ , and the molecular weight of polyacrylic acid is 100000 - 240000.

[0015] According to the above scheme, the hydrogel base layer and the detachable hydrogel interface layer contain methacryloyloxyethyl trimethyl ammonium chloride (MATAC) microspheres.

[0016] Methacryloyloxyethyl trimethyl ammonium chloride (MATAC) microspheres can improve the anti - swelling performance and mechanical properties of the hydrogel base layer and the detachable hydrogel interface layer, reducing the swelling rate during the process of being soaked in the solution.

[0017] According to the above scheme, the hydrogel base layer and the detachable hydrogel interface layer contain conductive materials.

[0018] According to the above scheme, the conductive materials in the hydrogel base layer and the detachable hydrogel interface layer can be independently selected from any one of LiCl, CaCl 2 , NaCl, PEDOT:PSS, polyaniline and polypyrrole.

[0019] Adding conductive materials can make the two - layer hydrogel have good electrical conductivity.

[0020] According to the above solution, the detachable hydrogel interface layer contains dopamine-modified sodium alginate (Alg-DA), acrylic acid (AAC), and N-acryloxysuccinimide (AAC-NHS). Alg-DA can endow the detachable hydrogel interface layer with good adhesion, while AAC and AAC-NHS can increase its wet adhesiveness, enabling the detachable hydrogel interface layer to stably adhere to the tissue surface.

[0021] According to the above solution, the inner circuit is branched, and a plurality of the electrode points are arranged at the ends of the branches of the inner circuit. The hydrogel base layer is divided into a plurality of non-connected regions corresponding one-to-one to the electrode points, and respectively covers the corresponding electrode points. The detachable hydrogel interface layer includes a plurality of non-connected regions, which respectively correspond one-to-one to the plurality of regions of the hydrogel base layer and are bonded to them.

[0022] In a second aspect, the present invention provides a method for using the above chemically detachable hydrogel electrode for physiological electrical measurement, including the following steps:

[0023] 1) Before use, add the polymer solution to the sides of the hydrogel base layer and the detachable hydrogel interface layer that need to be combined respectively, so that the polymer diffuses to form a polymer network, and then add the metal ion anchoring solution respectively to form an anchoring network of metal cations and the polymer. Then, make the sides of the two hydrogels that need to be combined face each other and squeeze for a certain time to combine the hydrogel base layer and the detachable hydrogel interface layer together;

[0024] 2) Adhere the detachable hydrogel interface layer to the human tissue for physiological electrical measurement;

[0025] 3) After use, soak the detachable hydrogel interface layer with the metal chelating agent solution, and make the metal chelating agent solution not exceed the bonding surface of the two hydrogels. After soaking for a certain time, the hydrogel base layer and the detachable hydrogel interface layer can be separated;

[0026] 4) Soak the hydrogel base layer with deionized water for a certain time to remove the residual metal chelating agent;

[0027] 5) When using again, replace the new hydrogel interface layer and repeat the above steps 1)-4).

[0028] In a third aspect, the present invention provides a preparation method for the above chemically detachable hydrogel electrode for physiological electrical measurement, including the following steps:

[0029] S1. Prepare methacryloyloxyethyl trimethyl ammonium chloride microspheres, dopamine-modified sodium alginate, benzophenone solution, polymer solution, metal ion anchoring solution, and metal chelating agent solution respectively;

[0030] S2. Prepare the precursor solutions of the hydrogel base layer and the detachable hydrogel interface layer respectively: Dissolve acrylamide, LiCl, D-sorbitol, and sodium alginate in deionized water, then add a photoinitiator and a crosslinking agent, and then add methacryloyloxyethyl trimethyl ammonium chloride microspheres. After mechanical stirring for a certain time, a precursor solution of the hydrogel base layer is made; Dissolve acrylamide, dopamine-modified sodium alginate, PEDOT:PSS, acrylic acid, and N-acryloxysuccinimide in deionized water, then add a photoinitiator and a crosslinking agent, and finally add methacryloyloxyethyl trimethyl ammonium chloride microspheres. After mechanical stirring for a certain time, a precursor solution of the detachable hydrogel interface layer is made;

[0031] S3. Prepare and form a flexible base layer, a flexible electrode array layer, and a flexible encapsulation layer;

[0032] S4. Immerse the area around the electrode points at the ends of each branch of the flexible electrode array layer in a benzophenone solution for a certain time;

[0033] S5. Pour the precursor solution of the hydrogel base layer onto the electrode points at the ends of each branch of the flexible electrode array layer through a mold. After ultraviolet irradiation, the hydrogel of the hydrogel base layer polymerizes on the electrode points. Pour the precursor solution of the detachable hydrogel interface layer into a mold of the same shape. After ultraviolet irradiation, the hydrogel of the detachable hydrogel interface layer polymerizes.

[0034] According to the above scheme, the photoinitiator is α-ketoglutaric acid, and the crosslinking agent is N,N'-methylenebisacrylamide.

[0035] This preparation method is simple and efficient, and the manufacturing cost is low. Description of the Drawings

[0036] Figure 1 It is an overall schematic exploded view of the chemically detachable hydrogel electrode for physiological electrical measurement in Embodiment 1 of the present invention;

[0037] Figure 2 It is a top view of the overall schematic of the chemically detachable hydrogel electrode for physiological electrical measurement in Embodiment 1 of the present invention;

[0038] Figure 3 It is the preparation method and usage method of the chemically detachable hydrogel electrode for physiological electrical measurement of the present invention;

[0039] Figure 4 It is the disassembly process of the chemically detachable hydrogel electrode for physiological electrical measurement in Embodiment 2 of the present invention.

[0040] In the figure, 1 is a flexible base layer, 2 is a flexible electrode array layer, 3 is a flexible encapsulation layer, 4 is a hydrogel base layer, 5 is a detachable hydrogel interface layer, 6 is a polymer solution, 7 is a metal ion anchoring solution, and 8 is a metal chelating agent solution. Detailed implementation mode

[0041] The principles and features of the present invention will be described below in conjunction with the accompanying drawings and specific embodiments. The examples given are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0042] Example 1

[0043] As Figure 1 and 2 shown, this example provides a chemically detachable hydrogel electrode for physiological electrical measurement, including a flexible base layer 1, a flexible encapsulation layer 3, a flexible electrode array layer 2 integrated with an internal circuit and one or more electrode points, a hydrogel base layer 4, a detachable hydrogel interface layer 5, and separately stored polymer solution 6, metal ion anchoring solution 7, and metal chelating agent solution 8. The flexible base layer 1 and the flexible encapsulation layer 3 jointly form a flexible frame body. The flexible electrode array layer 2 is arranged inside the flexible frame body, and one or more of the electrode points extend out of the flexible main frame through a window on the flexible encapsulation layer 3. The hydrogel base layer 4 is arranged on the flexible encapsulation layer 3 and covers the electrode points. The detachable hydrogel interface layer 5 is detachably arranged on the hydrogel base layer 4 for adhesion to human tissues. The solute in the polymer solution is a water-soluble polymer containing carboxyl groups, and the metal anchoring solution is a metal cation / citric acid aqueous solution, and the valence of the metal cation is divalent or trivalent. The detachable hydrogel interface layer 5 is combined with and detached from the hydrogel base layer 4 through the polymer solution 6, the metal ion anchoring solution 7, and the metal chelating agent solution 8;

[0044] During use, an anchoring network of metal cations and polymers is formed on the hydrogel base layer 4 and the detachable hydrogel interface layer 5 with the polymer solution 6 and the metal ion anchoring solution 7 respectively, and the two are anchored by external pressing. At the end of use, the anchoring network of metal cations and polymers is destroyed by soaking or dropping the metal chelating agent solution 8 to achieve the detachment of the detachable hydrogel interface layer 5.

[0045] During use, since the metal cations in the hydrogel base layer 4 and the detachable hydrogel interface layer 5 form metal chelation bonds with the carboxyl groups in the polymer, the two hydrogel layers are combined together. After use, soak with the metal chelating agent solution 8. When EDTANa 4When the solution 8 gradually penetrates into the interface layer of the two-layer gel, due to the stronger chelation between the metal cations and the ionic groups in the metal chelating agent solution 8, the chelation between the metal cations and the polymer is disrupted, thereby destroying the bond between the two-layer hydrogels, and the detachable hydrogel interface layer 5 is detached from the electrode.

[0046] The electrode of the present invention realizes the bonding and detachment of the detachable hydrogel interface layer 5 and the hydrogel base layer 4 through simple chemical solution immersion, and then realizes the reuse of the electrode by simply replacing the detachable hydrogel interface layer 5, reducing the cost and the risk of cross-infection.

[0047] Preferably, the mass fraction of the polymer in the polymer solution 6 is 5wt%-10wt%; the metal ion anchoring solution 7 includes a metal cation salt, citric acid and water, and the pH is adjusted to 2.7-3.3 with sodium hydroxide, wherein the mass fraction ranges of the metal cation salt and citric acid are 1wt%-4wt% and 1wt%-5wt% respectively, and the metal chelating agent solution 8 includes a metal chelating agent, acetic acid and water, and the mass fraction ranges of the metal chelating agent and acetic acid are 5wt%-15wt% and 0.5wt%-2wt% respectively.

[0048] The polymer is one or more of polyacrylic acid, hyaluronic acid, sodium alginate, polyaspartic acid and carboxymethyl cellulose; the metal cations are one or more of Fe 3+ 、Zr 4+ and Al 3+ ; the metal chelating agent is EDTANa 4 .

[0049] Preferably, in this embodiment, the above polymer is polyacrylic acid with a molecular weight of 100,000-240,000, and the metal cation is Fe 3+ . That is, the polymer solution is a polyacrylic acid solution, the metal ion anchoring solution is an Fe 3+ / citric acid anchoring solution, and the metal chelating agent solution is an EDTANa 4 solution.

[0050] The mass fraction of the polyacrylic acid solution is 5%; the formula of the Fe 3+ / citric acid anchoring solution is: 0.675g FeCl 3 ·6H 2 O, 0.7875g C 6 H 8 O 7 ·H 2 O, 20ml deionized water, 4.1ml NaOH solution with a concentration of 0.1g / ml; EDTANa 4The formulation of the solution is as follows: 5 g of tetrasodium ethylenediaminetetraacetate, 50 ml of deionized water, and 1.7 ml of acetic acid with a mass percentage of 36%.

[0051] Preferably, the hydrogel base layer 4 and the detachable hydrogel interface layer 5 contain a gel network formed by the polymerization of acrylamide.

[0052] Preferably, the hydrogel base layer 4 and the detachable hydrogel interface layer 5 contain methacryloyloxyethyltrimethylammonium chloride (MATAC) microspheres, which can improve the anti-swelling performance and mechanical properties of the hydrogel base layer 4 and the detachable hydrogel interface layer 5, and reduce the swelling rate during the process of being soaked in the solution.

[0053] Specifically, the preparation method of methacryloyloxyethyltrimethylammonium chloride (MATAC) microspheres is as follows:

[0054] S1. Dissolve 2 - 4 ml of a 60 wt% - 80 wt% methacryloyloxyethyltrimethylammonium chloride solution with a molecular weight of 207.7 MW and 20 - 100 mg of MBAA in a beaker containing a mixed solution of 50 - 100 ml of deionized water and cyclohexane (the mass ratio of water to cyclohexane is 1:3), stir magnetically for 15 min, where the rotation speed of the magnetic stirrer is 200 - 1000 r / min. After the solution is mixed evenly, degas for 0.5 - 1 h to obtain a methacryloyloxyethyltrimethylammonium chloride prepolymer solution.

[0055] S2. Add the above prepolymer solution to a three-necked flask for emulsion polymerization, add 0.02 - 0.04 wt% of KPS (potassium persulfate) by mass fraction, stir well with a magnetic stirrer, and at the same time heat in a water bath to 50°C - 80°C, where the rotation speed of the magnetic stirrer is 200 - 1000 r / min. After magnetic stirring for 2 - 5 h, pour it into a centrifuge tube, and use an oscillator to shake and wash it fully at 800 r / min for 10 min and then set aside.

[0056] S3. Centrifuge and wash the polymer after the above shaking and washing (rotation speed 13000, time 5 - 30 min) and then set aside.

[0057] S4. Add the washed polymer to a freeze dryer and freeze-dry it fully to obtain methacryloyloxyethyltrimethylammonium chloride (MATAC) microspheres.

[0058] Preferably, the hydrogel base layer 4 and the detachable hydrogel interface layer 5 contain a conductive material.

[0059] Preferably, the conductive materials in the hydrogel base layer 4 and the detachable hydrogel interface layer 5 can be independently selected from LiCl, CaCl 2, any one of NaCl, PEDOT:PSS, polyaniline, and polypyrrole. Adding a conductive material can endow the two-layer hydrogel with good electrical conductivity.

[0060] Preferably, the detachable hydrogel interface layer 5 contains dopamine-modified sodium alginate (Alg-DA), acrylic acid (AAC), and N-acryloxysuccinimide (AAC-NHS). Alg-DA can endow the detachable hydrogel interface layer 5 with good adhesion, while AAC and AAC-NHS can increase its wet adhesion, enabling the detachable hydrogel interface layer 5 to stably adhere to the tissue surface.

[0061] Specifically, the above-mentioned dopamine-modified sodium alginate (Alg-DA) can be prepared by the following method:

[0062] S1. Dissolve 10 - 20 g of MES (2-morpholinoethanesulfonic acid) and 2 - 4 g of NaCl in 500 - 1000 ml of deionized water, and then add 2 - 4 ml of 0.1 g / ml NaOH solution with a pH of 12 - 13 to obtain a MES solution with a pH of 5 - 6.

[0063] S2. Dissolve 1 g - 3 g of Alg (sodium alginate) in 40 - 100 ml of the MES solution, and then add 0.3 g - 0.8 g of EDC (1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride), 0.2 g - 0.8 g of NHS (N-hydroxysuccinimide), and 0.2 g - 0.8 g of ascorbic acid respectively. After activation by stirring with a magnetic stirrer at 200 - 600 rpm for 20 - 60 min, perform a degassing treatment for 10 - 30 min to prepare an Alg solution for standby.

[0064] S3. Dissolve 0.2 - 0.8 g of DA (dopamine hydrochloride) in 5 - 20 ml of the MES solution to prepare a DA solution for standby.

[0065] S4. Pour the DA solution into a separatory funnel and slowly add it to the Alg solution, and stir with a magnetic stirrer at 300 rpm for 6 - 24 h.

[0066] S5. Dialyze the well-stirred solution with deionized water for 48 h, and then place it in a freeze dryer to fully freeze-dry to obtain Alg-DA.

[0067] Preferably, the internal circuit is branched, and a plurality of the electrode points are arranged at the branch ends of the internal circuit. The hydrogel base layer 4 is divided into a plurality of non-connected regions corresponding one-to-one to the electrode points, and respectively covers the corresponding electrode points. The detachable hydrogel interface layer 5 includes a plurality of non-connected regions, which respectively correspond one-to-one to the plurality of regions of the hydrogel base layer 4 and are bonded to it.

[0068] Preferably, the precursor solution of the hydrogel base layer 4 is composed of the following components: acrylamide (AM), LiCl, D-sorbitol, α-ketoglutaric acid, MBAA crosslinking agent (N,N'-methylenebisacrylamide), sodium alginate, MATAC (methacryloyloxyethyl trimethyl ammonium chloride) microspheres, and deionized water. The mass fractions of acrylamide (AM), LiCl, D-sorbitol, α-ketoglutaric acid, MBAA crosslinking agent (N,N'-methylenebisacrylamide), sodium alginate, and methacryloyloxyethyl trimethyl ammonium chloride (MATAC) microspheres are respectively: 10-20 wt%, 1-5 wt%, 25-45 wt%, 0.1-0.5 wt%, 0.01-0.05 wt%, 0.1-0.5 wt%, 0.5-3 wt%, and the balance is water.

[0069] Preferably, the precursor solution of the detachable hydrogel interface layer 5 is composed of the following components: acrylamide (AM), dopamine-modified sodium alginate (Alg-DA), α-ketoglutaric acid, N,N'-methylenebisacrylamide (MBAA crosslinking agent), PEDOT:PSS, acrylic acid (AAC), N-acryloxysuccinimide (AAC-NHS), methacryloyloxyethyl trimethyl ammonium chloride (MATAC) microspheres, and deionized water. The mass fractions of acrylamide (AM), dopamine-modified sodium alginate (Alg-DA), α-ketoglutaric acid, N,N'-methylenebisacrylamide (MBAA crosslinking agent), PEDOT:PSS, acrylic acid (AAC), N-acryloxysuccinimide (AAC-NHS), and methacryloyloxyethyl trimethyl ammonium chloride (MATAC) microspheres are respectively: 10-20 wt%, 0.5-2.5 wt%, 0.1-0.5 wt%, 0.01-0.05 wt%, 3-15 wt%, 1-8 wt%, 0.1-0.8 wt%, 0.5-3 wt%, and the balance is water.

[0070] Preferably, the materials of the flexible base layer 1 and the flexible encapsulation layer 3 are both polydimethylsiloxane (PDMS).

[0071] Preferably, the material of the flexible electrode array layer 2 is an ECC conductive composite material.

[0072] The ECC conductive composite material is composed of silver nanowires and PDMS with a mass ratio of 3:1. The above materials are printed on the flexible base layer 1 and dried in a vacuum drying oven at 140-180 °C for 30-90 min to obtain the flexible electrode array layer 2.

[0073] Example 2

[0074] As Figure 3 and 4As shown in the figure, this embodiment provides a method for using the above-mentioned chemically detachable hydrogel electrode for physiological electrical measurement, including the following steps:

[0075] 1) Before use, as Figure 3 shown in ④⑤⑥ and ⑦ of the figure, add the polymer solution 6 to the side of the hydrogel base layer 4 and the detachable hydrogel interface layer 5 that need to be combined respectively, so that the polymer diffuses to form a polymer network, and then add the metal ion anchoring solution 7 respectively to form an anchoring network of metal cations and polymers. Then, make the sides of the two hydrogels that need to be combined face each other and squeeze for a certain time to make the hydrogel base layer 4 and the detachable hydrogel interface layer 5 combine together;

[0076] 2) Adhere the detachable hydrogel interface layer 5 to the human tissue for physiological electrical measurement;

[0077] 3) After use, as Figure 4 shown in ① and ② of the figure, soak the detachable hydrogel interface layer 5 with the metal chelating agent solution 8, and make sure that the metal chelating agent solution 8 does not exceed the joint surface of the two hydrogels. After soaking for a certain time, the hydrogel base layer 4 and the detachable hydrogel interface layer 5 can be separated;

[0078] 4) Soak the hydrogel base layer 4 with deionized water for a certain time to remove the residual metal chelating agent;

[0079] 5) When using again, replace the new hydrogel interface layer and repeat the above steps 1-4).

[0080] In step 1), drop the polymer solution 6 on the side of the hydrogel base layer 4 that needs to be combined with the detachable hydrogel interface layer 5, let it stand for sufficient diffusion, and then drop the metal ion anchoring solution 7 and let it stand for sufficient diffusion. The detachable hydrogel interface layer 5 is treated in the same way. Then, attach the detachable hydrogel interface layer 5 to the hydrogel base layer 4 and apply a certain opposite extrusion pressure. Specifically, weights, a press, etc. can be used. The lamination condition is lamination at a pressure of 5-10 N for 0.5-1 h.

[0081] Preferably, calculated by the volume of the gel, for every 2-16 cm 2 of the gel, the addition amount of the polymer solution 6 is 1 ml, and the addition amount of the metal ion anchoring solution is 1 ml.

[0082] Preferably, the standing time after dropping the polymer solution 6 is 30 min, and the standing time after dropping the metal ion anchoring solution 7 is 30 min.

[0083] In step 3), it is possible to choose to invert the electrode in the metal chelating agent solution 8, or to drop the metal chelating agent solution 8 on the detachable hydrogel interface layer 5 for soaking.

[0084] Specifically, when the reverse soaking method is selected, the soaking time is 3 - 6 h, specifically 6 h in this embodiment; when the dropping soaking method is selected, the soaking time is 3 - 6 h, specifically 6 h in this embodiment.

[0085] The soaking time in step 4) is 5 - 20 min, specifically 10 min in this embodiment.

[0086] Example 3

[0087] As Figure 3 shown, this embodiment provides the above - mentioned preparation method of the chemically detachable hydrogel electrode for physiological electrical measurement, including the following steps:

[0088] S1. Prepare methacryloyloxyethyl trimethyl ammonium chloride microspheres, dopamine - modified sodium alginate, benzophenone solution, polymer solution 6, metal ion anchoring solution 7 and metal chelating agent solution 8 respectively;

[0089] S2. Prepare the precursor solutions of the hydrogel base layer 4 and the detachable hydrogel interface layer 5 respectively: Dissolve acrylamide, LiCl, D - sorbitol, and sodium alginate in deionized water, then add a photoinitiator and a cross - linker, and then add methacryloyloxyethyl trimethyl ammonium chloride microspheres, and make the precursor solution of the hydrogel base layer 4 after mechanical stirring for a certain time; Dissolve acrylamide, dopamine - modified sodium alginate, PEDOT:PSS, acrylic acid and N - acryloxysuccinimide in deionized water, then add a photoinitiator and a cross - linker, and finally add methacryloyloxyethyl trimethyl ammonium chloride microspheres, and make the precursor solution of the detachable hydrogel interface layer 5 after mechanical stirring for a certain time;

[0090] S3. Prepare and form the flexible base layer 1, the flexible electrode array layer 2 and the flexible encapsulation layer 3. Specifically, it includes Figure 3 : ① Brush the ECC conductive composite material on the prepared flexible base layer 1 by screen printing, dry it at 160 °C for 1 h, and bond the flexible electrode array layer 2 to the flexible base layer 1; Bond the flexible encapsulation layer 3 to the flexible base layer. Double - sided tape or other adhesives can be used. In this embodiment, since PDMS is used as the material of the flexible base layer 1 and the flexible encapsulation layer 3, uncured PDMS can be brushed between the flexible base layer 1 and the flexible encapsulation layer 3, and then dried at 70 °C for 30 min to cure the PDMS and bond the flexible base layer 1 and the flexible encapsulation layer 3 together at the same time.

[0091] S4. Soak the area around the electrode points at each branch end of the flexible electrode array layer 2 with the benzophenone solution for a certain time;

[0092] S5. Pour the hydrogel base layer 4 precursor solution onto the electrode points at the ends of each branch of the flexible electrode array layer 2 through a mold. After irradiating with ultraviolet light for 45 minutes, the hydrogel base layer 4 cures and polymerizes on the electrode points, as specifically shown in Figure 3 Figure ③; Pour the removable hydrogel interface layer 5 precursor solution into a mold of the same shape. After irradiating with ultraviolet light, the removable hydrogel interface layer 5 polymerizes.

[0093] Preferably, the photoinitiator is α-ketoglutaric acid, and the crosslinking agent is N,N'-methylenebisacrylamide.

[0094] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A chemically detachable hydrogel electrode for physiological electrical measurement, characterized in that: It comprises a flexible substrate layer (1), a flexible packaging layer (3), a flexible electrode array layer (2) integrating an internal circuit and one or more electrode points, a hydrogel substrate layer (4), a detachable hydrogel interface layer (5), and a polymer solution (6), a metal ion anchoring solution (7), and a metal chelating agent solution (8) which are stored separately; The flexible base layer (1) and the flexible packaging layer (3) are jointly constructed to form a flexible frame body, the flexible electrode array layer (2) is arranged in the flexible frame body, one or more electrode points extend out of the flexible frame body through a window on the flexible packaging layer (3), the hydrogel base layer (4) is arranged on the flexible packaging layer (2) and covers the electrode points, and the detachable hydrogel interface layer (5) is detachably arranged on the hydrogel base layer (4) for adhesion to human tissue; The solute in the polymer solution (6) is a water-soluble polymer containing carboxyl groups, the metal anchoring solution (7) is a metal cation / citric acid aqueous solution, and the metal cation is divalent or trivalent; The detachable hydrogel interface layer (5) is combined with and detached from the hydrogel base layer (4) through the high molecular polymer solution (6), the metal ion anchoring solution (7) and the metal chelating agent solution (8).

2. The chemically detachable hydrogel electrode for physiological electrical measurement according to claim 1, characterized in that: The mass fraction of the high molecular polymer solution (6) is 2wt%-10wt%; The metal ion anchoring liquid (7) comprises a metal cation salt, citric acid and water, and the pH is adjusted to 2.7-3.3 using sodium hydroxide, wherein the mass fractions of the metal cation salt and citric acid are 1wt%-4wt% and 1wt%-5wt% respectively; The metal chelate solution (8) comprises a metal chelate, acetic acid and water, wherein the mass fractions of the metal chelate and the acetic acid are 5wt%-15wt% and 0.5wt%-2wt% respectively.

3. The chemically detachable hydrogel electrode for physiological electrical measurement according to claim 1 or 2, characterized in that: The high molecular polymer is one or more of polyacrylic acid, hyaluronic acid, sodium alginate, polyaspartic acid and carboxymethyl cellulose; the metal cation is Fe 3+ 、Zr 4+ and Al 3+ One or more of; the metal chelator is EDTANa4.

4. The chemically detachable hydrogel electrode for physiological electrical measurement according to claim 1, characterized in that: The hydrogel base layer (4) and the detachable hydrogel interface layer (5) contain methacryloyloxyethyl trimethylammonium chloride microspheres.

5. The chemically detachable hydrogel electrode for physiological electrical measurement according to claim 4, characterized in that: The hydrogel base layer (4) and the detachable hydrogel interface layer (5) contain conductive materials.

6. The chemically detachable hydrogel electrode for physiological electrical measurement according to claim 5, characterized in that: The conductive materials in the hydrogel base layer (4) and the detachable hydrogel interface layer (5) can be independently selected from any one of LiCl, CaCl2, NaCl, PEDOT:PSS, polyaniline and polypyrrole.

7. The chemically detachable hydrogel electrode for physiological electrical measurement according to claim 6, characterized in that: The detachable hydrogel interface layer (5) contains dopamine-modified sodium alginate, acrylic acid and N-acryloyloxysuccinimide.

8. The chemically detachable hydrogel electrode for physiological electrical measurement according to claim 1, characterized in that: The internal circuit is branched, and the plurality of electrode points are arranged at the branch ends of the internal circuit. The hydrogel base layer (4) is divided into a plurality of mutually unconnected regions corresponding one-to-one to the electrode points, and respectively covers the corresponding electrode points. The detachable hydrogel interface layer (5) includes a plurality of mutually unconnected regions, which respectively correspond one-to-one to the plurality of regions of the hydrogel base layer (4) and are bonded thereto.

9. The method for using the chemically detachable hydrogel electrode for physiological electrical measurement according to any one of claims 1 to 8, characterized in that: The steps include: 1) Before use, the polymer solution is added to the sides of the hydrogel base layer (4) and the detachable hydrogel interface layer (5) to be combined, so that the polymer diffuses to form a polymer network, and then metal ion anchoring liquid is added to form an anchoring network of metal cations and polymers, and then the sides of the two layers of hydrogel to be combined are placed opposite to each other and squeezed for a certain period of time to combine the hydrogel base layer (4) and the detachable hydrogel interface layer (5) together; 2) adhering the detachable hydrogel interface layer (5) to human tissue to perform physiological electrical measurements; 3) After use, the detachable hydrogel interface layer (5) is soaked in a metal chelating agent solution, and the metal chelating agent solution does not exceed the bonding surface of the two layers of hydrogel. After soaking for a certain period of time, the hydrogel base layer (4) and the detachable hydrogel interface layer (5) can be separated; 4) soaking the hydrogel base layer (4) in deionized water for a certain period of time to remove the residual metal chelating agent; 5) When using again, replace the new hydrogel interface layer (5) and repeat the above steps 1) to 4).

10. The method for preparing a chemically detachable hydrogel electrode for physiological electrical measurement according to claim 7, characterized in that: The steps include: S1. preparing methacryloyloxyethyl trimethylammonium chloride microspheres, dopamine-modified sodium alginate, benzophenone solution, polymer solution (6), metal ion anchoring solution (7) and metal chelating agent solution (8); S2. Preparing precursor solutions of the hydrogel base layer (4) and the detachable hydrogel interface layer (5) respectively: dissolving acrylamide, LiCl, D-sorbitol and sodium alginate in deionized water, adding a photoinitiator and a cross-linking agent, and then adding methacryloyloxyethyl trimethyl ammonium chloride microspheres, and mechanically stirring for a certain period of time to prepare a hydrogel base layer (4) precursor solution; dissolving acrylamide, dopamine-modified sodium alginate, PEDOT:PSS, acrylic acid and N-acryloyloxy succinimide in deionized water, adding a photoinitiator and a cross-linking agent, and finally adding methacryloyloxyethyl trimethyl ammonium chloride microspheres, and mechanically stirring for a certain period of time to prepare a detachable hydrogel interface layer (5) precursor solution; S3. Preparing a flexible substrate layer (1), a flexible electrode array layer (2) and a flexible encapsulation layer (3); S4. Soaking the area around the electrode point at the end of each branch of the flexible electrode array layer (2) with a benzophenone solution for a certain period of time; S5. The precursor solution of the hydrogel base layer (4) is poured through a mold onto the electrode points at the end of each branch of the flexible electrode array layer (2). After irradiation with ultraviolet light, the hydrogel base layer (4) polymerizes at the electrode points. The precursor solution of the detachable hydrogel interface layer (5) is poured into a mold of the same shape. After irradiation with ultraviolet light, the hydrogel of the detachable hydrogel interface layer (5) is polymerized.

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