Low-temperature-resistant hydrogel electrode patch as well as preparation method and application thereof

Abstract

The invention discloses a low-temperature-resistant hydrogel electrode patch and a preparation method and application thereof, and the preparation method comprises the following steps: mixing water, betaine and calcium chloride in proportion to obtain a eutectic solvent; dissolving octadecyl methacrylate in the deep eutectic solvent, then adding tannic acid, acrylic acid, ammonium persulfate and N, N-methylene bisacrylamide, and uniformly mixing; and finally, adding guar gum, uniformly mixing, and standing to obtain the low-temperature-resistant hydrogel. Dynamic covalent bonds formed between the acrylic acid and the octadecyl methacrylate form a first chemical cross-linked network; hydrophobic bonds of octadecyl methacrylate are mutually crosslinked, the hydrogen-bond interaction of guar gum and the coordination of carboxyl of acrylic acid and Ca < 2 + > metal in calcium chloride jointly form a physically crosslinked second network. The calcium chloride can improve the conductivity of the hydrogel, the eutectic solvent can inhibit the generation of ice crystals and can provide conductive ions, and the low-temperature resistance of the low-temperature-resistant hydrogel electrode patch is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrogel electrodes, and in particular relates to a low-temperature resistant hydrogel electrode patch and a preparation method and application thereof. Background Art

[0002] The statements herein merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] With the advancement of medical technology, electrode patches have become an important tool in the current medical field and are widely used in electrophysiological signal detection and electrical stimulation therapy. In recent years, researchers have introduced a variety of new materials to improve the performance of electrode patches. Hydrogel electrode patches have attracted attention due to their good biocompatibility and ionic conductivity. Their advantage is that they can fit closely to the skin and improve the quality of signal acquisition. It can be used for physiological signal detection and rehabilitation treatment, support telemedicine, and meet personalized medical needs. Combined with wireless communication and biosensing technology, hydrogel electrode patches can also realize remote monitoring and real-time transmission of physiological signals.

[0004] However, under low temperature conditions, the water in the hydrogel easily freezes, resulting in a significant reduction in the conductivity and adhesion of the hydrogel electrode, thereby affecting the detection quality of electrophysiological signals and the effect of electrical stimulation therapy. In order to solve the problem of easy freezing of hydrogel electrode patches and broaden the scope of use of hydrogel electrode patches, it is of great significance to prepare low-temperature resistant hydrogel electrode patches. Low-temperature resistant hydrogel electrode patches can inhibit the formation of ice crystals in low-temperature environments and maintain stable flexibility and adhesion, thereby ensuring that electrophysiological signals can still be accurately and reliably collected under cold conditions.

[0005] In recent years, reports on cryoresistant hydrogels have been made by adding different antifreeze agents to the hydrogels, such as inorganic salts (lithium chloride, calcium chloride, etc.), ionic liquids, organic solvents (glycerol), etc. However, although this cryoresistant hydrogel composed of inorganic salts has high conductivity, the salting-out effect produced by the inorganic salts will lead to uneven internal ion dispersion, resulting in reduced mechanical properties. Although ionic liquids have good thermal and chemical stability, the high viscosity of ionic liquids will affect the flexibility of hydrogels; and some ionic liquids may be harmful to the human body or the environment, which limits their application in the medical and biological fields. Although organic solvents can enhance the antifreeze and moisture retention of hydrogels, the addition of organic solvents will affect the conductive properties of hydrogels. Summary of the invention

[0006] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a low-temperature resistant hydrogel electrode patch and a preparation method and application thereof.

[0007] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0008] In a first aspect, the present invention provides a method for preparing a low-temperature resistant hydrogel, comprising the following steps:

[0009] Mixing water, betaine and calcium chloride in proportion to obtain a deep eutectic solvent;

[0010] Dissolve octadecyl methacrylate in the low eutectic solvent, then add tannic acid, acrylic acid, ammonium persulfate and N,N-methylenebisacrylamide and mix them evenly. As an ester compound, octadecyl methacrylate has a long carbon chain and can introduce hydrophobicity, so that the hydrogel has a certain hydrophilicity while maintaining a certain hydrophilicity. It can be copolymerized with acrylic acid monomers to form a hydrogel network structure with specific functions; tannic acid is a natural polyphenol small molecule with antioxidant and antibacterial effects, which makes it more widely used in the biomedical field; acrylic acid is an unsaturated carboxylic acid with double bonds, which has strong hydrophilicity and activity. It can form hydrogen bonds and van der Waals forces with water molecules, thereby enhancing the moisturizing properties and stability of the hydrogel; ammonium persulfate is an initiator, which generates free radicals by decomposition to initiate the polymerization reaction of the monomer; N,N-methylenebisacrylamide is a cross-linking agent that can form a covalent cross-linking network with other monomers or polymers.

[0011] Finally, guar gum is added, mixed, and allowed to stand for a set time to obtain a low-temperature resistant hydrogel. Guar gum is a natural polysaccharide with good water solubility. Guar gum can be used as a stabilizer to improve the stability of the hydrogel. It can also form a dynamic cross-linking network with other components to give the hydrogel good mechanical properties.

[0012] The low temperature resistant hydrogel of the present invention is a double network structure, and this double network structure makes the hydrogel have higher strength and toughness. The hydrogel can better disperse stress when subjected to external force, thereby improving its mechanical properties such as tensile resistance. Conductive materials are introduced into the network to make it have good electrical conductivity. In addition, the hydrogel with this double network structure can also have good biocompatibility and air permeability. In the biomedical field, this hydrogel can fit closely with the skin, which helps to improve the comfort of patients.

[0013] Specifically, the dynamic covalent bonds formed between acrylic acid and octadecyl methacrylate constitute the first chemical cross-linking network; the hydrophobic bonds inside octadecyl methacrylate cross-link each other, the hydrogen bonds inside guar gum, and the carboxyl groups inside acrylic acid and CaCl2 2+ The metal coordination together forms a second network of physical crosslinks.

[0014] Calcium chloride is a conductive filler and the low eutectic solvent is a modifier. Calcium chloride can improve the conductivity of the hydrogel, and the low eutectic solvent can both inhibit the formation of ice crystals and provide conductive ions, thereby improving the low temperature resistance of the low temperature resistant hydrogel electrode patch.

[0015] In some embodiments, in the low eutectic solvent, the mass ratio of betaine, calcium chloride and water is 8-12:20-25:60-70; preferably 10-11:22-23:60-70.

[0016] In some embodiments, the mass ratio of the low eutectic solvent, octadecyl methacrylate, tannic acid, acrylic acid, ammonium persulfate, N,N-methylenebisacrylamide and guar gum is 54-55: 2-4: 2.6-4: 30-40: 0.1-0.2: 0.05-0.1: 4-6.

[0017] Preferably, the mass ratio of the low eutectic solvent, octadecyl methacrylate, tannic acid, acrylic acid, ammonium persulfate, N,N-methylenebisacrylamide and guar gum is 54-55:2-3:3-4:33-38:0.1-0.2:0.07-0.9:4.7-5.3; specifically 54.34:2.33:3.1:35:0.15:0.08:5.

[0018] In some embodiments, the preparation process of the low-temperature resistant hydrogel is carried out at a relatively high temperature, specifically 25-60°C.

[0019] In a second aspect, the present invention provides a low-temperature resistant hydrogel electrode patch prepared by the preparation method.

[0020] In a third aspect, the present invention provides application of the low-temperature resistant hydrogel electrode patch in electrophysiological signal detection.

[0021] The beneficial effects achieved by one or more embodiments of the present invention are as follows:

[0022] (1) In the low-temperature resistant hydrogel electrode patch provided by the present invention, the dynamic covalent bonds formed between acrylic acid and octadecyl methacrylate constitute the first chemical cross-linking network; the hydrophobic bonds inside octadecyl methacrylate are cross-linked with each other, the hydrogen bonds inside guar gum, and the carboxyl groups inside acrylic acid and CaCl in the calcium chloride react to form a first chemical cross-linking network. 2+ The metal coordination effect together forms a second network of physical cross-linking. Calcium chloride can improve the conductivity of the hydrogel, and the low eutectic solvent can not only inhibit the formation of ice crystals, but also provide conductive ions to improve the low-temperature resistance of the low-temperature hydrogel electrode patch.

[0023] (2) After the low-temperature-resistant hydrogel electrode patch is connected to the wire, it can be attached to different parts of the human body to monitor electrophysiological signals.

[0024] Compared with traditional metal electrode patches, hydrogel electrode patches have the following advantages:

[0025] a: High water content and strong conductivity: The main material of hydrogel electrode is hydrogel, which can effectively avoid leakage caused by drying during treatment. At the same time, hydrogel has the characteristics of low resistance and strong conductivity, making the current conversion into pulse signal stronger.

[0026] b: Comfort and fit: The hydrogel electrode sheet fits the human skin better during application, and is more comfortable and fits more closely, which makes the patient feel more comfortable during use and increases the comfort of treatment.

[0027] In summary, hydrogel as an electrode patch has obvious advantages in conductivity and comfort compared to traditional metal electrode patches. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0029] Figure 1 Schematic diagram of the synthesis process of the low-temperature resistant hydrogel electrode patch of the present invention;

[0030] Figure 2 Graphs showing the toughness and Young's modulus of the low-temperature resistant hydrogel electrode patches a, b and c obtained after changing the amount of acrylic acid in Example 2 and the low-temperature resistant hydrogel electrode patch obtained in Example 1;

[0031] Figure 3 The graphs are toughness and Young's modulus of low-temperature resistant hydrogel electrode patches d, e and f obtained after changing the amount of guar gum in Example 3 and the low-temperature resistant hydrogel electrode patch obtained in Example 1;

[0032] Figure 4 The conductivity diagram of the environmental detection of the low-temperature resistant hydrogel electrode patch is changed in Example 1;

[0033] Figure 5 Schematic diagram of electrophysiological signals measured after the low-temperature resistant hydrogel electrode patch obtained in Example 1 is connected to a wire;

[0034] Figure 6 Graphs of human electromyographic signals detected by the low-temperature resistant hydrogel electrode patch obtained in Example 1 and the commercial electrode patch when a grip force that first increases and then decreases is applied;

[0035] Figure 7This is a comparison diagram of human electromyographic signals detected by the low-temperature resistant hydrogel electrode patch obtained in Example 1 and the commercial electrode patch when a grip force that first increases and then decreases is applied;

[0036] Figure 8 The electromyographic signal diagrams of the low-temperature resistant hydrogel electrode patch and the commercial electrode patch obtained in Example 1 when the human arm is performing relaxation-clenching-stretching activities;

[0037] Fig. 9 The electrocardiogram of a human body detected by the low-temperature resistant hydrogel electrode patch obtained in Example 1 and the commercial electrode patch;

[0038] Fig.10 This is a comparison diagram of the amplitudes of the low-temperature resistant hydrogel electrode patch obtained in Example 1 and the commercial electrode patch when detecting the electrocardiogram signal of the human body;

[0039] Fig.11 This is a comparison chart of the signal-to-noise ratio when the low-temperature resistant hydrogel electrode patch obtained in Example 1 and the commercial electrode patch detect the electrocardiogram signal of the human body;

[0040] Fig.12 The electrocardiogram signals of the low-temperature resistant hydrogel electrode patch and the commercial electrode patch obtained in Example 1 before and after human body movement are detected;

[0041] Fig.13 The DSC graph obtained after the DSC test of the low-temperature resistant hydrogel electrode patch obtained in Example 1 is as follows:

[0042] Fig.14 This is a graph of human electromyographic signals detected when the low-temperature-resistant hydrogel electrode patch obtained in Example 1 was frozen at -20°C for 24 hours and a gradually increasing grip force was applied;

[0043] Fig.15 This is a diagram of human electrocardiogram signals detected after the low-temperature-resistant hydrogel electrode patch obtained in Example 1 was frozen at -20°C for 24 hours. DETAILED DESCRIPTION

[0044] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0045] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with specific embodiments.

[0046] Example 1

[0047] according to Figure 1 The synthesis process of synthesizing low-temperature resistant hydrogel electrode patches is as follows:

[0048] (1) At 30° C., 10 g of betaine and 22 g of calcium chloride were added to 65 ml of deionized water, and stirred at 700 r / min for 10 min until all the solids were dissolved to form a deep eutectic solvent;

[0049] (2) 0.15 g of octadecyl methacrylate, 0.2 g of tannic acid, 2.25 g of acrylic acid, 0.01 g of ammonium persulfate, and 0.005 g of N,N-methylenebisacrylamide were added to the deep eutectic solvent in sequence, and stirred at 700 r / min for 0.5 h at a temperature of 35° C. until the mixture was completely dissolved;

[0050] (3) Add 0.32 g of guar gum to the solution of step (2), and stir at 700 r / min for 0.5 h at 30° C. until it is completely dissolved. After standing in a high temperature environment of 60° C. for 8 hours, a low-temperature resistant hydrogel electrode patch is obtained.

[0051] (4) Cut the low-temperature resistant hydrogel into a 10 mm × 10 mm circular shape, peel off the protective film of the non-woven fabric therapy electrode, and stick the prepared hydrogel electrode to the raised part in the middle of the non-woven fabric therapy electrode, exposing the sticky surface, and stick it to the desired part. Connect the electrode patch to the wire of the low-frequency pulse instrument to facilitate the transmission of electrical signals.

[0052] Example 2

[0053] The difference from Example 1 is that the amount of acrylic acid is changed to 1.4 g, 1.8 g, and 2.79 g, respectively, and the obtained low-temperature resistant hydrogel electrode patches are a, b, and c, respectively.

[0054] Example 3

[0055] The difference from Example 1 is that the content of guar gum is changed to 0.19 g, 0.25 g and 0.39 g respectively, and the obtained low-temperature resistant hydrogel electrode patches are d, e and f respectively.

[0056] Figure 2 This is a comparison chart of the toughness and Young's modulus of the low-temperature resistant hydrogel electrodes a, b and c obtained after changing the amount of acrylic acid in Example 2 and the low-temperature resistant hydrogel electrode obtained in Example 1; Figure 3 This is a comparison chart of the toughness and Young's modulus of the low-temperature resistant hydrogel electrodes d, e and f obtained after changing the amount of guar gum in Example 3 and the low-temperature resistant hydrogel electrode obtained in Example 1. Figure 2-3 The results show that the optimal mass ratio of raw materials in low-temperature resistant hydrogel can be determined.

[0057] Figure 4 This is a conductivity diagram of the low-temperature resistant hydrogel electrode patch obtained in Example 1 after the hydrogel electrode patch is placed in different environments for a specified time; it can be seen from the figure that changing the storage environment of the electrode patch will not change much, indicating that the hydrogel electrode patch has good stability and low volatility.

[0058] Figure 5 It is a schematic diagram of the electrophysiological signals measured after the low-temperature resistant hydrogel electrode patch obtained in Example 1 is connected to the wire; the low-temperature resistant hydrogel electrode patch is adhered to the surface of human skin, such as the arm, chest, etc., and then connected to the data collector through the wire to record the response test to the human body signal.

[0059] First, the myoelectric signals of the low-temperature resistant hydrogel electrode patch obtained in Example 1 and the commercial electrode patch (model: X-1 disposable ECG electrode, silver / silver chloride·Ag / AgCl, merchant: Hangzhou Xunda Radio Equipment Co., Ltd.) when the grip force was first increased and then decreased were detected; the results are as follows Figure 6 As shown, it can be seen that when the same weight of grip force is applied, the obtained electromyographic signal is basically stable; when different weights of grip force are applied, the intensity of the electromyographic signal increases with the increase of grip force, and decreases with the decrease of grip force. The detected electromyographic signal proves the effectiveness of the low-temperature resistant hydrogel electrode patch of the present invention in detecting human electrophysiological signals.

[0060] Figure 7 As shown, the amplitude values ​​of the low-temperature resistant hydrogel electrode of the present invention and the traditional commercial electrode (model: X-1 disposable ECG electrode, silver / silver chloride·Ag / AgCl, merchant: Hangzhou Xunda Radio Equipment Co., Ltd.) in the electromyographic signal are calculated. It can be clearly seen from the figure that the amplitude value of the low-temperature resistant hydrogel electrode of Example 1 of the present invention is higher than that of the traditional commercial electrode, which proves that the low-temperature resistant hydrogel electrode patch is superior to the traditional commercial electrode patch and can achieve higher signal transmission efficiency and a more comfortable wearing experience.

[0061] The low-temperature resistant hydrogel electrode patch obtained in Example 1 and the commercial electrode patch were used to detect the electromyographic signal of the human arm during movement. The results are as follows: Figure 8 As shown. By analyzing these signals, researchers or medical professionals can understand information such as muscle activity patterns, collaborative work, and force output. In the future, it can provide valuable data support for sports analysis, training optimization, and rehabilitation evaluation.

[0062] Fig. 9The low-temperature resistant hydrogel electrode patch obtained in Example 1 and a commercial electrode patch (model: X-1 disposable ECG electrode, silver / silver chloride·Ag / AgCl, merchant: Hangzhou Xunda Radio Equipment Co., Ltd.) detected human ECG signals. This shows that the low-temperature resistant hydrogel electrode patch of the present invention can detect different electrophysiological signals of the human body.

[0063] Fig.10 It shows that when detecting ECG signals, the signal intensity detected by the low-temperature resistant hydrogel electrode patch of Example 1 of the present invention is significantly higher than that of the traditional commercial electrode patch (model: X-1 disposable ECG electrode, silver / silver chloride·Ag / AgCl, merchant: Hangzhou Xunda Radio Equipment Co., Ltd.); in addition, in addition to calculating the amplitude value, the signal-to-noise ratio of the two is also calculated. Fig.11 It shows that the signal-to-noise ratio of the low-temperature resistant hydrogel electrode patch of the present invention is significantly higher than that of the traditional commercial electrode patch. In summary, it is shown that the low-temperature resistant hydrogel electrode patch of the present invention can gradually replace the commercial electrode patch and become the mainstream choice in the medical field.

[0064] Fig.12 As shown, the cryogenic-resistant hydrogel electrode patch obtained in Example 1 and the commercial electrode patch detected the ECG signals before and after human exercise. Exercise has an important impact on heart function, and proper exercise can strengthen heart muscles and improve the working efficiency of the heart. However, excessive or inappropriate exercise may cause excessive burden on the heart and even cause heart problems. Therefore, the cryogenic-resistant hydrogel electrode patch of the present invention is of great significance for monitoring heart rate changes before and after exercise, evaluating exercise effects and preventing exercise risks.

[0065] Fig.13 The DSC test was performed on the low-temperature resistant hydrogel electrode patch prepared in Example 1 of the present invention. It can be seen from the figure that even at minus 70°C, the material in the electrode patch did not decompose, proving that the low-temperature resistant hydrogel electrode of the present invention has good antifreeze properties.

[0066] In order to further test the stability of the low-temperature resistant hydrogel electrode of the present invention under low-temperature conditions, the low-temperature resistant hydrogel electrode prepared in Example 1 was frozen at -20°C for 24 hours, and the electrophysiological signals of the human body were detected. The results are as follows: Fig.14 , 15 As shown; it was found that the hydrogel electrode patch can still quickly and accurately monitor human electromyographic signals even after being frozen at -20°C for 24 hours (such as Fig.14 ) and ECG signals (such as Fig.15 ), indicating that the low-temperature resistant hydrogel electrode patch of the present invention does have good low-temperature resistance.

[0067] In summary, through the evaluation of comparative studies, it can be proved that the cryogenic hydrogel electrode patch has more advantages than traditional commercial electrode patches and also has good low-temperature resistance. This advantage makes the cryogenic hydrogel electrode patch have a wider application prospect in the fields of electrophysiological signal detection.

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a low-temperature resistant hydrogel electrode patch, characterized in that: The steps include: Mixing water, betaine and calcium chloride in proportion to obtain a deep eutectic solvent; Dissolving octadecyl methacrylate in the low eutectic solvent, then adding tannic acid, acrylic acid, ammonium persulfate and N,N-methylenebisacrylamide, and mixing well; Finally, guar gum is added, mixed, and allowed to stand for a set time to obtain a low-temperature resistant hydrogel.

2. The method for preparing the low-temperature resistant hydrogel electrode patch according to claim 1, characterized in that: In the low eutectic solvent, the mass ratio of betaine, calcium chloride and water is 8-12:20-25:60-70.

3. The method for preparing the low-temperature resistant hydrogel electrode patch according to claim 2, characterized in that: In the low eutectic solvent, the mass ratio of betaine, calcium chloride and water is 10-11:22-23:60-70.

4. The method for preparing the low-temperature resistant hydrogel electrode patch according to claim 1, characterized in that: The mass ratio of the low eutectic solvent, octadecyl methacrylate, tannic acid, acrylic acid, ammonium persulfate, N,N-methylenebisacrylamide and guar gum is 54-55:2-4:2.6-4:30-40:0.1-0.2:0.05-0.1:4-6.

5. The method for preparing the low-temperature resistant hydrogel electrode patch according to claim 4, characterized in that: The mass ratio of the low eutectic solvent, octadecyl methacrylate, tannic acid, acrylic acid, ammonium persulfate, N,N-methylenebisacrylamide and guar gum is 54-55: 2-3: 3-4: 33-38: 0.1-0.2: 0.07-0.9: 4.7-5.

3.

6. The method for preparing the low-temperature resistant hydrogel electrode patch according to claim 5, characterized in that: The mass ratio of low eutectic solvent, octadecyl methacrylate, tannic acid, acrylic acid, ammonium persulfate, N,N-methylenebisacrylamide and guar gum is 54.34:2.33:3.1:35:0.15:0.08:

5.

7. The method for preparing the low-temperature resistant hydrogel electrode patch according to claim 1, characterized in that: The preparation process of low-temperature resistant hydrogel is carried out at a relatively high temperature.

8. The method for preparing the low-temperature resistant hydrogel electrode patch according to claim 7, characterized in that: The temperature during the preparation of the low-temperature resistant hydrogel is 25-60°C, preferably 30-60°C.

9. A low temperature resistant hydrogel electrode patch, characterized in that: Prepared by the preparation method described in any one of claims 1 to 8.

10. Use of the low-temperature resistant hydrogel electrode patch according to claim 9 in electrophysiological signal detection.

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