A self-adhering flexible electrode

Abstract

The present application relates to the technical field of adhesive, in particular to an adhesive, a preparation method thereof and a self-adhesive flexible electrode. Sodium polyglutamate is dissolved in water to obtain a first solution. A modifying agent is dissolved in water to obtain a second solution, so that the modifying agent dissociates to form halogen ions and modifying ions, the modifying ions include N + groups connected with three substituents, and the group at the distal end is a long-chain alkyl with a chain length greater than or equal to 8. The first solution and the second solution are mixed, the precipitate is collected and dried to obtain an adhesive substance. The adhesive substance forms a viscous layer and is compounded with a flexible and conductive electrode layer to form a self-adhesive flexible electrode. Since polyglutamic acid has high biocompatibility, the N + group has a sterilization effect, and the long-chain alkyl has a hydrophobic effect, the adhesive has good biological affinity, antibacterial property and waterproof property, and also has strong adhesive capacity, which facilitates the stable adhesion of the self-adhesive flexible electrode to the skin surface, does not damage the skin and accurately outputs bioelectric signals.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of adhesives, in particular to an adhesive, a preparation method thereof and a self-adhesive flexible electrode. BACKGROUND

[0002] In the field of medical health, human body electrical signals are often collected by electrodes to achieve the purpose of monitoring signs, diagnosis or monitoring the course of disease. For example, various cardiac abnormalities such as atrial fibrillation are important risk sources of ischemic stroke. Long-term, continuous and accurate monitoring of key physiological signals such as electrocardiogram of high-risk population is of great significance for early warning and prevention of stroke. However, traditional rigid electrodes have poor biocompatibility and are difficult to be fixed on the human body for a long time, which is not conducive to long-term and continuous monitoring of the signs of patients.

[0003] At present, some wearable devices and smart homes choose flexible electrodes to realize continuous monitoring of human body electrical signals. Flexible electrodes have excellent flexibility, stretchability and low immune rejection characteristics, can realize seamless fitting with human tissues, can flexibly adapt to skin deformation and realize non-inductive wearing, thereby significantly improving the collection accuracy and long-term monitoring stability of physiological signals such as electrocardiogram and electroencephalogram, and providing key support for cutting-edge technologies such as brain-computer interface and neural prosthesis. However, existing flexible electrodes, such as widely used silver / silver chloride (Ag / AgCl) gel electrodes, are prone to adhesion failure and skin allergy when attached for a long time, and bacteria are prone to grow at the interface, which is not conducive to skin health. SUMMARY

[0004] The purpose of the present application is to provide an adhesive which is not easy to damage the skin, a preparation method thereof and a self-adhesive flexible electrode.

[0005] To achieve the above purpose, in a first aspect, the present application provides the following technical solution:

[0006] A preparation method of an adhesive, comprising:

[0007] dissolving sodium polyglutamate in water to obtain a first solution;

[0008] dissolving a modifying agent in water to obtain a second solution, so that the modifying agent dissociates to form halide ions and modifying ions, the modifying ions comprising N + groups connected with three substituents, and the group far away from the N + group at one end of the long-chain alkyl group has a chain length greater than or equal to 8;

[0009] mixing the first solution and the second solution, filtering and collecting the precipitate generated by the reaction, and drying to obtain an adhesive substance.

[0010] Optionally, the modifier is an antibacterial agent, including one or more of lauroyl arginine ethyl hydrochloride, 1-octadecylamine, N,N-dimethyl hydrochloride, dodecyltrimethylammonium chloride, dodecyltrimethylammonium bromide, tetradecyltrimethylammonium chloride, tetradecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, octadecyltrimethylammonium chloride, and octadecyltrimethylammonium bromide, wherein the average molecular weight of the sodium polyglutamate is any value from 700,000 Da to 2,000,000 Da.

[0011] Optionally, the method for preparing the adhesive further includes:

[0012] The adhesive is dissolved in an organic solvent to obtain an adhesive.

[0013] Optionally, the organic solvent is anhydrous ethanol, and the mass ratio of the adhesive to the organic solvent is any value in the range of 1:(4~8).

[0014] Optionally, the mass ratio of the sodium polyglutamate to the modifier is any value in the range of 1:(1~3).

[0015] Optionally, the reaction temperature of the first solution and the second solution is any value between 20°C and 30°C, and the reaction time of the first solution and the second solution is any value between 2h and 6h.

[0016] Secondly, the present invention also provides an adhesive prepared by the above-described method for preparing an adhesive.

[0017] Thirdly, the present invention also provides a self-adhesive flexible electrode, characterized in that it comprises an electrode layer and an adhesive layer stacked and interconnected, wherein the electrode layer is constructed of a flexible conductive material, and the adhesive layer comprises the aforementioned adhesive.

[0018] Optionally, the electrode layer is hydrogel-like, comprising a swelling solvent and a water-soluble polymer, poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate, and a spinning aid dissolved in the swelling solvent, wherein the spinning aid is a macromolecular polyanionic electrolyte.

[0019] Optionally, the one or more of polyglutamic acid, hyaluronic acid and sodium hyaluronate, the one or more of polyvinyl alcohol, polyethylene glycol, four-arm polyethylene glycol, polyacrylamide and polyethylene oxide, the swelling solvent is deionized water or a two-phase solvent formed by mixing dimethyl sulfoxide and deionized water, the electrode layer is formed by mutual adhesion and welding of gel fibers extruded by the electrospinning method of the precursor solution, the mass ratio of the spinning aid to the water-soluble polymer is any value in 1: (4~9), the total concentration of the water-soluble polymer, the poly (3, 4-ethylenedioxythiophene) -polystyrene sulfonate and the spinning aid in the precursor solution is any value in 2wt%~6wt%, the average molecular weight of the water-soluble polymer is any value in 120000Da~200000Da, and the average molecular weight of the spinning aid is any value in 1000000Da~2000000Da.

[0020] The beneficial effects of the present application are that: after sodium polyglutamate is dissolved in water, the carboxyl groups in the monomers dissociate to form a plurality of free carboxylate ions to obtain polyglutamic acid (PGA) ions. The modifier is dissolved in water to dissociate to form a modified ion carrying a positive charge. The carboxylate ions and the hydrophilic end of the modified ions, i.e. N + ions are electrostatically attracted and combined. The long-chain alkyl group away from the N + ion is a hydrophobic segment, which spontaneously aggregates towards the inside in an aqueous solution to form a hydrophobic core, while the hydrophilic backbone of PGA and the hydrophilic end of the modifier are exposed on the outside to form a hydrophilic shell. The hydrophobic core avoids direct contact with water, reducing the surface tension of the complex. The hydrophilic shell can resist the penetration of external water molecules or ions, preventing the complex from dissociating due to dilution or ion interference. With the help of the hydrophobic segment, sodium polyglutamate and the modifier form a stable complex and precipitate from the aqueous solution, and after filtration and drying, an adhesive substance is obtained. The adhesive substance uses PGA as the main chain of the material, has good biological affinity, and is not easy to cause damage to the skin. The N + ion of the modifier can be electrostatically adsorbed to the negatively charged bacterial cell membrane, thereby destroying the membrane structure, so that the adhesive substance has good antibacterial effect. The long-chain alkyl group of the modifier can insert and disturb the lipid membrane of bacteria, thereby achieving synergistic antibacterial effect. Some modifiers can also achieve antibacterial effect through other mechanisms. When the adhesive substance is coated on the surface of the substrate, the hydrophobic effect of the long-chain alkyl group can enhance the adsorption and stability of the adhesive substance at the interface, and also can combine with the lipid layer on the surface of the skin through hydrophobic interaction, thereby enhancing the interfacial adhesion. The carboxylate and N + ions can form strong non-covalent bonds with proteins, lipids and other substances in the stratum corneum of the skin through hydrogen bonding, ion-dipole interactions and other mechanisms, thereby making the adhesive have strong and stable skin adhesion.

[0021] The above description is only a summary of the technical solutions of the present application. In order to make the technical means of the present application clearer and can be implemented according to the content of the description, the following will be described in detail with the preferred embodiments of the present application and with the help of the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 Flow chart of the preparation method of the adhesive shown in embodiment one of the present application;

[0023] Figure 2 Skin-electrode contact impedance diagram of the self-adhesive flexible electrode and the medical gel electrode at different frequencies shown in embodiment one of the present application;

[0024] Figure 3 Electrocardiogram monitoring diagram of the self-adhesive flexible electrode and the medical gel electrode shown in embodiment one of the present application;

[0025] Figure 4 Peeling strength diagram of the self-adhesive flexible electrode on the mirror stainless steel plate shown in embodiment one and embodiment four of the present application;

[0026] Figure 5 Interface toughness diagram of the self-adhesive flexible electrode on the mirror stainless steel plate shown in embodiment one and embodiment four of the present application;

[0027] Figure 6 Conductivity statistical diagram of the self-adhesive flexible electrode shown in embodiment one and embodiment five of the present application. DETAILED DESCRIPTION

[0028] The technical solutions of the present application will be described in detail below with the help of the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0029] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0030] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "linking" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0031] In addition, the technical features involved in the different embodiments of the application described below can be combined with each other as long as there is no conflict.

[0032] The present application claims a preparation method of an adhesive, comprising:

[0033] S1, dissolving sodium polyglutamate in water to obtain a first solution.

[0034] S2, dissolving a modifying agent in water to obtain a second solution, so that the modifying agent dissociates to form halide ions and modifying ions, the modifying ions comprising N + group connected with three substituents, and the group far from the N + group is a long-chain alkyl group, and the chain length of the long-chain alkyl group is greater than or equal to 8.

[0035] S3, mixing the first solution and the second solution, collecting the precipitate generated by the reaction by filtration, and drying to obtain an adhesive.

[0036] The chain length of the long-chain alkyl group may, for example, be any one of 8, 9, 10, 12, 15, 20 and 22.

[0037] After sodium polyglutamate is dissolved in water, the carboxyl groups in the monomers dissociate to form a plurality of free carboxylate ions to obtain polyglutamic acid (PGA) ions. After the modifying agent is dissolved in water, it dissociates to form positively charged modifying ions. The carboxylate ions and the hydrophilic end of the modifying ions, i.e. the N + ion, are electrostatically attracted and combined. The long-chain alkyl group far from the N + ion is a hydrophobic segment, which spontaneously aggregates towards the inside in an aqueous solution to form a hydrophobic core, while the hydrophilic backbone of PGA and the hydrophilic end of the modifying agent are exposed on the outside to form a hydrophilic shell. The hydrophobic core avoids direct contact with water, reducing the surface tension of the complex. The hydrophilic shell can resist the penetration of external water molecules or ions, preventing the complex from dissociating due to dilution or ion interference. With the assistance of the hydrophobic segment, sodium polyglutamate and the modifying agent form a stable complex and precipitate out of the aqueous solution, and after filtration and drying, an adhesive is obtained. The adhesive uses PGA as the main chain of the material, has good biological affinity, and is not easy to cause damage to the skin. The N +The ions can be electrostatically adsorbed to the negatively charged bacterial cell membrane, thereby destroying the membrane structure, so that the adhesion has good antibacterial effect. The long-chain alkyl of the modifier can insert and disturb the lipid membrane of the bacteria, thereby achieving antibacterial effect in cooperation. Some modifiers can also achieve antibacterial effect through other mechanisms. When the adhesion is coated on the surface of the substrate, the hydrophobic effect of the long-chain alkyl can enhance the adsorption and stability of the adhesion at the interface, and also can be combined with the lipid layer on the skin surface through hydrophobic interaction to enhance the interfacial adhesion. The carboxylate and N + The ions can be combined with proteins, lipids and the like in the stratum corneum of the skin through hydrogen bonds, ion-dipole interactions and the like to form strong non-covalent bonds, thereby making the adhesive have strong and stable skin adhesion.

[0038] In some embodiments, the modifier is an antibacterial agent, including one or more of lauroyl arginine ethyl ester hydrochloride, 1-octadecylamine, N,N-dimethyl hydrochloride, dodecyltrimethylammonium chloride, dodecyltrimethylammonium bromide, tetradecyltrimethylammonium chloride, tetradecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, octadecyltrimethylammonium chloride and octadecyltrimethylammonium bromide. Selecting a modifier with strong antibacterial properties helps to improve the antibacterial properties of the adhesive and reduce the risk of bacteria growing on the adhesive interface in a humid environment and damaging the skin.

[0039] In some embodiments, the average molecular weight of the sodium polyglutamate is any value between 700000 Da and 2000000 Da, for example, it can be any value between 700000 Da, 1000000 Da, 1500000 Da and 2000000 Da, which helps to ensure the adhesion of the adhesive.

[0040] In some embodiments, the preparation method of the adhesive further comprises:

[0041] S4, dissolving the adhesion in an organic solvent to obtain an adhesive.

[0042] The adhesion is dispersed by the organic solvent to form a homogeneous liquid adhesive, which facilitates uniform coating of the adhesive on the adhesive interface. When the adhesive is coated, the adhesive flows and infiltrates the micro-relief of the adhesive interface, and the organic solvent volatilizes to form mechanical interlocking after the adhesive is formed, which helps to improve the adhesion.

[0043] In some embodiments, the organic solvent is anhydrous ethanol, and the mass ratio of the adhesion agent to the organic solvent is 1: any value in (4-8), for example, can be any value in (1:4), (1:5), (1:6), (1:7) and (1:8). Anhydrous ethanol is less likely to damage the skin and has better volatility. Restricting the reconstitution ratio helps to ensure that the adhesive has moderate flowability, is easy to apply, and has a moderate content of organic solvent, which can quickly evaporate to solidify the adhesive, thereby helping to improve the adhesion of the adhesive.

[0044] In some embodiments, the mass ratio of the sodium polyglutamate to the modifying agent is 1: any value in (1-3), for example, can be any value in (1:1), (1:1.5), (1:2), (1:2.5), and (1:3), which helps to ensure that the adhesive has good antibacterial properties while ensuring the viscosity and biocompatibility of the adhesive.

[0045] In some embodiments, the reaction temperature of the first solution and the second solution is any value in 20-30℃, for example, can be any value in 20℃, 22℃, 24℃, 26℃, 28℃ and 30℃, and the reaction time of the first solution and the second solution is any value in 2-6h, for example, can be any value in 2h, 3h, 4h, 5h and 6h, which helps to ensure that the sodium polyglutamate and the modifying agent are fully reacted.

[0046] In a second aspect, the present application also provides an adhesive prepared by the above-mentioned method for preparing an adhesive.

[0047] In a third aspect, the present application also provides a self-adhesive flexible electrode, characterized in that it comprises an electrode layer and an adhesive layer stacked and connected to each other, the electrode layer is made of a flexible conductive material, and the adhesive layer comprises the above-mentioned adhesive.

[0048] The adhesive forms the adhesive layer, and the electrode layer formed by the flexible conductive material is attached to the skin surface. Since the adhesive contains a large amount of long-chain alkyl, the conductivity of the adhesive layer is effectively improved, ensuring efficient and stable transmission of electrical signals between the skin and the electrode layer. Since the adhesive has good adhesion and water resistance, it helps to ensure that the electrode layer is firmly attached to the skin surface. Since the adhesive has good biocompatibility and antibacterial properties, it can effectively inhibit the growth of bacteria and the irritation of the adhesive layer to the skin, thereby reducing the risk of skin damage.

[0049] In some embodiments, the electrode layer is a hydrogel, which comprises a swelling solvent, a water-soluble polymer, poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate, and a spinning aid, and the spinning aid is a macromolecular polyanion electrolyte.

[0050] In the poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS), PSS is a strong polyelectrolyte, easy to dissolve in water and poor in conductivity, while PEDOT is an electrically active component, which is difficult to dissolve in water itself, but as a conjugated polymer, it carries a positive charge due to the loss of electrons in the main chain in solution, thereby adsorbing to PSS to achieve dissolution. When PEDOT:PSS and macromolecular polyanion electrolyte are dissolved in water at the same time, the macromolecular polyanion electrolyte dissociates to form anions each of which has a strong negative charge, and PEDOT is adsorbed to the electronegative groups of each monomer of the macromolecular polyanion electrolyte under the action of electrostatic attraction, and is firmly combined with the macromolecular polyanion electrolyte, so that the electrode layer can carry a relatively high content of PEDOT, which helps to improve the conductivity of the electrode layer. The long-chain water-soluble polymer and the long-chain macromolecular polyanion electrolyte are intertwined with each other, which helps to make the electrode layer swell into a gel state, and does not affect the electronegativity of the macromolecular polyanion electrolyte, and helps to form a water gel with stable structure.

[0051] In some embodiments, the co-spinning agent includes one or more of polyglutamic acid, hyaluronic acid, and sodium hyaluronate, the water-soluble high molecular polymer is one or more of polyvinyl alcohol, polyethylene glycol, four-arm polyethylene glycol, polyacrylamide, and polyethylene oxide, the swelling solvent is deionized water, or a two-phase solvent formed by mixing dimethyl sulfoxide with deionized water, and the electrode layer is formed by mutual adhesion and welding of gel fibers extruded from the precursor solution by electrospinning. The mass ratio of the co-spinning agent to the water-soluble high molecular polymer is any value in the range of 1:(4~9), for example, it can be any value in the range of (1:4), (1:5), (1:6), (1:8.5), and (1:9). The total concentration of the water-soluble high molecular polymer, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), and the co-spinning agent in the precursor solution is any value in the range of 2wt%~6wt%, for example, it can be any value in the range of 2wt%, 3wt%, 4wt%, 5wt%, and 6wt%. The average molecular weight of the water-soluble high molecular polymer is any value in the range of 120000Da~200000Da, for example, it can be any value in the range of 120000Da, 140000Da, 160000Da, 180000Da, and 200000Da. The average molecular weight of the co-spinning agent is any value in the range of 1000000Da~2000000Da, for example, it can be any value in the range of 1000000Da, 1200000Da, 1400000Da, 1600000Da, 1800000Da, and 2000000Da.

[0052] The addition of dimethyl sulfoxide in the swelling solvent helps to improve the conductivity of the electrode layer. The spinning solution is extruded in the form of electrospinning to form gel fibers, and the gel fibers are mutually adhered and welded on the receiver to form an electrode layer. The preparation method is simple, facilitates large-scale production of self-adhesive flexible electrodes, and facilitates the formation of ultra-thin electrode layers. In the process of electrospinning, the electric field pulls the PEDOT towards the receiver, so that the co-spinning agent closely connected with the PEDOT and the water-soluble polymer polymer move towards the receiver together, and the nozzle extrudes the homogeneous gel fibers. Restricting the content ratio of PEDOT:PSS and co-spinning agent helps to improve the mutual constraint ability between them and ensure the homogeneity of the gel fibers. Restricting the total content of water-soluble polymer, PEDOT:PSS and co-spinning agent helps to ensure that the gel fibers are in gel form and have certain fluidity, so that the gel fibers are mutually welded and flow flat to form a uniform electrode layer.

[0053] For details, please refer to the following examples.

[0054] Example 1:

[0055] Please refer to Figure 1 The preparation method of the adhesive shown in a preferred embodiment of the present application comprises:

[0056] S1, dissolve sodium polyglutamate in water to obtain a first solution.

[0057] S2, dissolve the modifying agent in water to obtain a second solution, so that the modifying agent dissociates to form halide ions and modifying ions, the modifying ions include N + group connected with three substituents, and the group far away from the N + group is a long-chain alkyl group, and the chain length of the long-chain alkyl group is greater than or equal to 8.

[0058] S3, mix the first solution and the second solution, filter and collect the precipitate generated by the reaction, and dry to obtain the adhesive.

[0059] In step S1, sodium polyglutamate is purchased from Shanghai Aldrin Biochemical Technology Co., Ltd., and the product number is P1506123, and the specification with an average molecular weight ≥700000 Da is selected. Sodium polyglutamate is dissolved in deionized water to form a first solution with a mass fraction of 1wt%.

[0060] In step S2, lauroyl arginine ethyl ester hydrochloride (ELA) is used as the modifying agent, and ELA is purchased from Shanghai Aldrin Biochemical Technology Co., Ltd., and the product number is E304112. ELA is dissolved in deionized water to form a second solution with a mass fraction of 1wt%.

[0061] In step S3, the first solution and the second solution are mixed at a mass ratio of 1:1 at room temperature, which is 24℃. After stirring for 2h, the precipitate generated in the reaction is collected by filtration, and the obtained precipitate is vacuum freeze-dried for 48h, and then ground into powder by a pulverizer to obtain the adhesive substance. The adhesive substance is stored in a dry container for standby use.

[0062] In this embodiment, the method for preparing the adhesive further comprises:

[0063] S4, dissolving the adhesive substance in an organic solvent to obtain the adhesive.

[0064] In step S4, anhydrous ethanol is used as the organic solvent, and 1g of the adhesive substance is dissolved in 6g of the organic solvent, and then magnetically stirred for 2h to obtain a homogeneous viscous adhesive.

[0065] In this embodiment, the adhesive is prepared on demand, and only the adhesive substance stored in a dry environment is re-dissolved before the adhesion operation is performed.

[0066] In this embodiment, the adhesive is coated on the surface of the electrode layer cut from the flexible conductive film to form a self-adhesive flexible electrode.

[0067] The method for preparing the flexible conductive film comprises:

[0068] S5, 0.45g of polyvinyl alcohol (PVA), 0.1g of polyglutamic acid (PGA), 10g of deionized water, and 5g of dimethyl sulfoxide (DMSO) with a purity of 99.9% are mixed, and magnetically stirred at a speed of 500rpm at 92℃ for 100min to obtain a clear sol. 15g of PEDOT:PSS aqueous dispersion with a concentration of 1.3wt% is continuously added, and the magnetic stirring is continuously carried out at a speed of 500rpm for 11h to obtain a uniform spinning solution. Observation shows that the spinning solution is black blue.

[0069] S6, the spinning solution is injected into the syringe of the electrospinning machine, the spinning voltage is set to 16kV, the pushing rate is 0.85mL / h, and the receiving distance is 5cm. A roller collector with a diameter of 85mm and a length of 300mm is used, and an aluminum foil is laid on the surface of the roller collector, and the collection is carried out at a speed of 250rpm for 8h to obtain a uniform flexible conductive film.

[0070] The aluminum foil with the flexible conductive film attached to the surface is soaked in deionized water for 30min until the flexible conductive film is separated from the aluminum foil. The flexible conductive film is cut into a size of 1.5cm×1.5cm to form an electrode layer.

[0071] The PVA in this embodiment is PVA from Sigma-Aldrich, a brand of Merck, with a product code of 363103 and an average molecular weight of 146000 Da-186000 Da. The PGA is purchased from Shanghai Yuan Ye Biotechnology Co., Ltd., with a product code of S27136 and an average molecular weight of 2000000 Da. The PEDOT:PSS is diluted from a paste commercial product, and the product from Clevios, a brand of Heraeus Group, Germany, with a product code of SV4.

[0072] The binder is uniformly coated on the surface of the electrode layer by screen printing, and after drying and curing, a sticky layer adhering to the surface of the electrode layer is obtained, which together forms a self-adhesive flexible electrode, which is named PPP. The temperature for drying and curing is any value in the range of 20-45°C, and in this embodiment, it is 30°C. The time for drying and curing is any value in the range of 10-30 min, and in this embodiment, it is 25 min. In other embodiments, the binder can also be coated by spin coating or blade coating.

[0073] The electrode layer and the self-adhesive flexible electrode in this embodiment are subjected to antibacterial testing.

[0074] According to the GB / T 31402 standard, Staphylococcus aureus, Escherichia coli and Candida albicans are inoculated on the surface of plate count agar by the streak method, and cultured in a 37°C constant temperature incubator for 24 h. Single colonies are picked and inoculated in 25 mL suspension medium, and cultured in a 37°C constant temperature shaker at a speed of 200 r / min for 12 h, and the bacterial precipitate is obtained by centrifugation. The bacterial liquid is adjusted to a concentration of 1×10 7 CFU / mL with sterile phosphate buffered saline (PBS), and diluted 10 times with fresh liquid medium to obtain a working concentration of 1×10 6 CFU / mL of bacterial suspension. In the viable bacterial count experiment, the self-adhesive flexible electrode is vertically placed in a 12-well culture plate, 25 μL of bacterial suspension is added to the center area, and a 1 cm×1 cm polyethylene (PE) film is covered to achieve uniform spreading. After 24 h of static culture at 37°C, 3 mL of PBS buffer is added for ultrasonic elution for 2 min, and the eluate is collected and subjected to continuous gradient dilution. 100 μL of diluted bacterial liquid is uniformly coated on the agar plate, and cultured at 37°C for 24 h, and the number of bacterial colonies is counted. The detection results show that the antibacterial rate of the self-adhesive flexible electrode on Staphylococcus aureus, Escherichia coli and Candida albicans is greater than 99.8%.

[0075] The 180° peeling strength of the sticky layer of the self-adhesive flexible electrode when attached to pigskin is detected, and the value of the peeling strength is about 1.8 N / cm, indicating that the binder and the self-adhesive flexible electrode have good skin adhesion ability.

[0076] The conductivity of the self-adhesive flexible electrode was detected, and the conductivity of the self-adhesive flexible electrode in this embodiment was greater than 3500 S / m.

[0077] A commercial dry electrode with a product category of disposable foam ECG electrode and a model of SF06 was purchased from Shanghai Yingke ECG Medical Products Co., Ltd., and a medical gel electrode Ag / AgCl with a product category of disposable non-woven ECG electrode and a model of SN12 was purchased from Shanghai Yingke ECG Medical Products Co., Ltd., and the two were compared with the self-adhesive flexible electrode PPP in this embodiment in terms of performance.

[0078] The three electrodes were attached to the human skin respectively, and it was detected that the skin-electrode contact impedance of the self-adhesive flexible electrode in this embodiment at a frequency of 10 Hz was about 20 kΩ, the skin-electrode contact impedance of the medical gel electrode Ag / AgCl at a frequency of 10 Hz was about 90 kΩ, and the skin-electrode contact impedance of the commercial dry electrode at a frequency of 10 Hz was greater than 90 kΩ. Please refer to Figure 2 , the skin-electrode contact impedance of the self-adhesive flexible electrode PPP and the medical gel electrode Ag / AgCl at different frequencies was detected respectively, and it can be seen that compared with the commercial dry electrode and the medical gel electrode Ag / AgCl, the self-adhesive flexible electrode in this embodiment has higher sensitivity and accuracy when used for ECG monitoring or EMG monitoring, and has a longer service life.

[0079] The three electrodes were attached to the skin surface of three volunteers respectively for ECG detection, and were worn continuously for 8 hours with daily activities during the period. There was sweat secretion at the interface between the electrode and the skin when the detection was completed. The medical gel electrode Ag / AgCl and the self-adhesive flexible electrode PPP could obtain analyzable ECG signals during the whole period, but the medical gel electrode Ag / AgCl appeared signal noise increase due to gel drying in the later period, and the commercial dry electrode appeared intermittent signal and serious motion artifact after sweating. The ECG monitoring maps output by the medical gel electrode Ag / AgCl and the self-adhesive flexible electrode PPP are shown in Figure 3 , it can be seen that the ECG signal output by the self-adhesive flexible electrode in this embodiment is clear, the baseline is stable, the right ventricular excitation potential amplitude is high, the signal quality is comparable to that of the medical gel electrode, and the signal stability is better than that of the commercial dry electrode under the condition of slight sweating after long-time attachment.

[0080] After 8h of wearing and mechanical removal of the electrode, the skin area covered by the self-adhesive flexible electrode PPP had no obvious redness or residual colloid; the skin area covered by the medical gel electrode Ag / AgCl had slight redness; and the skin area covered by the commercial dry electrode had red marks due to friction. It can be seen that the self-adhesive flexible electrode PPP in this embodiment has good skin affinity.

[0081] The three electrodes were respectively cultured in the bacterial culture medium for 24 h, and only obvious bacteriostatic ring was observed around the self-adhesive flexible electrode PPP, and the surfaces of the medical gel electrode Ag / AgCl and the commercial dry electrode were both covered with bacteria. It can be seen that the self-adhesive flexible electrode PPP in this embodiment has good bacteriostatic performance.

[0082] The self-adhesive flexible electrode in this embodiment was attached to the skin, and after 96 h, the self-adhesive flexible electrode was still fixed on the skin surface. The self-adhesive flexible electrode patch was peeled off, and anhydrous ethanol was added dropwise to release the glue during peeling. During the process of attaching and peeling the self-adhesive flexible electrode to the skin, the skin had no obvious discomfort.

[0083] Example Two:

[0084] The difference between this embodiment and Example One is that the modifier in this embodiment is hexadecyl trimethyl ammonium chloride.

[0085] It was detected that the 180° peeling strength of the self-adhesive flexible electrode obtained in this embodiment to pigskin was about 1.7 N / cm. The self-adhesive flexible electrode was attached to the surface of pigskin covered with simulated sweat, and the adhesion retention rate thereof was about 88% after 4 h, showing excellent water hydration resistance. The conductivity of the self-adhesive flexible electrode obtained in this embodiment was greater than 3400 S / m, and the 24 h antibacterial rate thereof to Staphylococcus aureus, Escherichia coli and Candida albicans was all greater than 99.8%.

[0086] Example Three:

[0087] The difference between this embodiment and Example One is that the modifier in this embodiment is octadecyl trimethyl ammonium bromide.

[0088] It was detected that the 180° peeling strength of the self-adhesive flexible electrode obtained in this embodiment to pigskin was about 2.1 N / cm. The self-adhesive flexible electrode was attached to the uneven skin surface of joints and elbows, and both exhibited good conformal adhesion and elastic recovery. The conductivity of the self-adhesive flexible electrode obtained in this embodiment was greater than 3300 S / m, and the 24 h antibacterial rate thereof to Staphylococcus aureus, Escherichia coli and Candida albicans was all greater than 99.9%.

[0089] Example Four:

[0090] The difference between this embodiment and Example One is that the mass of the organic solvent during reconstitution was adjusted to 4 g and 8 g, respectively. The mass fraction of the adhesive agent in Example One was about 14.29 wt%, and the mass fractions of the two adhesive agents in this embodiment were about 20 wt% and 11.11 wt%, respectively.

[0091] The 180° peeling strength of the self-adhesive flexible electrode obtained in the embodiment and the self-adhesive flexible electrode obtained in the embodiment one on the mirror stainless steel plate is detected respectively, and the detection result is shown in Table 1. Figure 4 It can be seen that increasing the mass fraction of the adhesive substance in the adhesive can help to improve the adhesive capacity of the adhesive layer.

[0092] The interface toughness of the self-adhesive flexible electrode obtained in the embodiment and the self-adhesive flexible electrode obtained in the embodiment one on the mirror stainless steel plate is detected respectively, and the detection result is shown in Table 2. Figure 5 It can be seen that increasing the mass fraction of the adhesive substance in the adhesive can help to improve the shear resistance and the peeling resistance of the self-adhesive flexible electrode.

[0093] Embodiment five:

[0094] The difference between the embodiment and the embodiment one is that the spinning aids in the embodiment are sodium hyaluronate (SH), hyaluronic acid (HA) and high molecular sodium hyaluronate (HPSH) respectively. The SH in the embodiment is purchased from Beijing Wakai Biological Technology Co., Ltd., and the product number is A56250; the HA is purchased from Tokyo Chemical Industry Co., Ltd. (TCI), and the product number is H0595; and the HPSH is purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., and the product number is H293496.

[0095] The conductivity of each self-adhesive flexible electrode in the embodiment is detected respectively, and the detection result is shown in Table 3. Figure 6 It can be seen that the conductivity of the self-adhesive flexible electrode is greatly affected by the selection of the spinning aid.

[0096] The self-adhesive flexible electrode formed by coating the adhesive in the application on the hydrogel electrode can be firmly and durably attached to the skin surface, and is not easy to stimulate or damage the skin. The moderate hydrophobicity of the adhesive effectively resists the invasion of sweat and environmental moisture, prevents the adhesion force from being attenuated due to excessive hydration, and ensures the adhesion reliability in long-term use in a dynamic humid environment.

[0097] The technical features of the above-described embodiments can be combined arbitrarily. In order to make the description simple, all possible combinations of the technical features in the above-described embodiments are not described, but as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the description.

[0098] The above-described embodiments only express several embodiments of the application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that for ordinary skilled persons in the art, without departing from the concept of the application, a number of modifications and improvements can be made, which are within the scope of protection of the application. Therefore, the protection scope of the patent of the application should be subject to the appended claims.

Claims

1. A self-adhesive flexible electrode, characterized in that, The device includes a stacked and interconnected electrode layer and an adhesive layer. The electrode layer is constructed of a flexible conductive material, and the adhesive layer includes an adhesive prepared by the following steps: Sodium polyglutamate was dissolved in water to obtain the first solution; The modifier is dissolved in water to obtain a second solution. The modifier is an antibacterial agent, including one or more of lauroyl arginine ethyl ester hydrochloride, 1-octadecylamine, N,N-dimethyl hydrochloride, dodecyltrimethylammonium chloride, dodecyltrimethylammonium bromide, tetradecyltrimethylammonium chloride, tetradecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, octadecyltrimethylammonium chloride, and octadecyltrimethylammonium bromide. The average molecular weight of the sodium polyglutamate is any value between 700,000 Da and 2,000,000 Da. The mass ratio of the sodium polyglutamate to the modifier is any value between 1 and (1 to 3). The first solution and the second solution were mixed, the precipitate generated by the reaction was collected by filtration, and dried to obtain the adhesive substance; The adhesive is dissolved in an organic solvent to obtain an adhesive; The electrode layer is hydrogel-like and includes a swelling solvent and a water-soluble polymer, poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate, and a spinning aid dissolved in the swelling solvent. The spinning aid includes one or more of polyglutamic acid, hyaluronic acid, and sodium hyaluronate; the water-soluble polymer is one or more of polyvinyl alcohol, polyethylene glycol, tetra-arm polyethylene glycol, polyacrylamide, and polyethylene oxide; the swelling solvent is deionized water or a two-phase solvent formed by mixing dimethyl sulfoxide and deionized water; the electrode layer is formed by bonding and welding gel fibers extruded from the precursor liquid through electrospinning; the mass ratio of the spinning aid to the water-soluble polymer is any value of 1:(4~9); the total concentration of the water-soluble polymer, the poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate, and the spinning aid in the precursor liquid is any value of 2wt%~6wt%; the average molecular weight of the water-soluble polymer is any value of 120000Da~200000Da; and the average molecular weight of the spinning aid is any value of 1000000Da~2000000Da.

2. The self-adhesive flexible electrode as described in claim 1, characterized in that, The organic solvent is anhydrous ethanol, and the mass ratio of the adhesive to the organic solvent is any value in the range of 1:(4~8).

3. The self-adhesive flexible electrode as described in claim 1 or 2, characterized in that, The reaction temperature of the first solution and the second solution is any value between 20℃ and 30℃, and the reaction time of the first solution and the second solution is any value between 2h and 6h.

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