Anti-freezing hydrogel with high antibacterial property as well as preparation method and application of anti-freezing hydrogel

Abstract

The invention discloses anti-freezing hydrogel with high antibacterial property and a preparation method and application thereof.The preparation method comprises the steps that THMA, AM and SBMA are dissolved in a binary mixed solvent of water and glycerin and stirred and dispersed, and a suspension A is formed; adding a PA solution, an initiator and a cross-linking agent into the suspension A, and uniformly stirring to obtain a precursor solution; according to the method, the process is simple, the design is reasonable, the polymer hydrogel with both the anti-freezing water locking performance and the antibacterial performance is obtained, sensing application of the hydrogel material in a complex environment is achieved, and the method has wide application prospects.

Description

Technical Field

[0001] This invention belongs to the field of hydrogel preparation technology, and relates to a highly antibacterial antifreeze hydrogel, its preparation method and application. Background Technology

[0002] In the healthcare field, with the increasing demand for refined wound management and intelligent health monitoring, the research and development of novel medical materials has attracted much attention. Antibacterial hydrogels, with their excellent biocompatibility, flexibility, and multifunctionality, have shown great potential in wound management and health monitoring, becoming one of the current research hotspots. Currently, the dominant wound dressings on the market are still traditional types, such as bandages and medical gauze. While these traditional dressings can meet basic wound coverage needs to a certain extent, their functions are relatively limited. In contrast, novel hydrogel dressings have significant advantages. Their physical properties are similar to human soft tissue, possessing excellent plasticity and elasticity, allowing them to better conform to the shape of the wound; at the same time, they can create a moist and suitable environment for wound healing, helping to accelerate the healing process and improve treatment outcomes.

[0003] However, existing hydrogel technologies face numerous challenges in practical applications. Most hydrogels use water as the dispersion medium, a characteristic that makes them difficult to adapt to complex and variable environmental conditions. In harsh environments, especially at low temperatures, the performance of hydrogels is severely affected, preventing them from functioning stably and thus limiting their application in human health monitoring.

[0004] To address this issue, researchers are actively exploring improvement methods, primarily by adding antifreeze agents to the hydrogel system to enhance its antifreeze and water-retention properties. For example, Chinese patent CN202211190490.7 discloses a method for preparing a highly flexible and ionicly conductive antifreeze hydrogel. By adding glycerol to the hydrogel system, hydrogen bonds are formed between glycerol and water molecules, effectively inhibiting the formation of ice crystals at low temperatures and giving the hydrogel excellent antifreeze properties. Furthermore, Chinese patent CN202410904292.5 discloses a conductive antifreeze hydrogel and its preparation method, which not only incorporates alcohol-based antifreeze agents but also introduces a high-water-content salt solution to ensure conductivity.

[0005] While these research findings have improved the antifreeze properties of hydrogels to some extent, existing technologies still have significant shortcomings. Current hydrogels struggle to simultaneously achieve both antibacterial and antifreeze properties; some exhibit excellent antibacterial effects but poor antifreeze capabilities, while others demonstrate good antifreeze properties but insufficient antibacterial activity. This imbalance in performance severely restricts the widespread application of hydrogels in wound management and health monitoring. Therefore, developing novel hydrogels with both antibacterial and antifreeze properties has become a crucial issue that urgently needs to be addressed. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides an antifreeze hydrogel with high ionic conductivity, its preparation method, and its application, thereby solving the technical problem that hydrogels in the prior art cannot simultaneously achieve antibacterial and antifreeze properties.

[0007] This invention is achieved through the following technical solution: A method for preparing a highly antibacterial antifreeze hydrogel includes the following steps: S1: Dissolve THMA, AM, and SBMA in a binary solvent of water and glycerol, stir and disperse to form suspension A; S2: Add PA solution, initiator and crosslinking agent to the suspension A, stir evenly to obtain precursor liquid; S3: The precursor fluid undergoes a free radical polymerization reaction to obtain the highly ionicly conductive antifreeze hydrogel.

[0008] Preferably, the ratio of water to glycerol in the binary solvent of water and glycerol is (250~50):(50~250) by mass.

[0009] Preferably, the ratio of SBMA, THMA and AM by mass parts is (45~65):(23~40):(15~20).

[0010] Preferably, in step S2, the ratio of the PA solution to water in the binary solvent is (50~200):(100~250) by mass.

[0011] Preferably, in step S2, the ratio of the initiator to the crosslinking agent is (1~3):(3~1) by mass.

[0012] Preferably, in step S2, the initiator is at least one selected from ammonium persulfate, potassium persulfate, azobisisobutylamidine hydrochloride, azobisisobutylimidazoline hydrochloride, azobiscyanopentanoic acid, and azobisisopropylimidazoline.

[0013] Preferably, in step S2, the crosslinking agent is at least one selected from polyethylene glycol diglycidyl ether, N,N'-methylenebisacrylamide, hydrazine peroxide, diallyl phthalate, divinylbenzene, diisocyanate, dicumyl peroxide, di-tert-butyl peroxide, and styrene.

[0014] Preferably, in step S3, the temperature of the free radical polymerization reaction is 30~100℃ and the time is 2~10h.

[0015] A highly antibacterial antifreeze hydrogel was prepared by the above method; the antifreeze hydrogel has an electrical conductivity of 0.47~3.60 S / m, an adhesion strength of 5.35~23.11 KPa, and a water holding capacity of 39.2%~65.5%.

[0016] The above-mentioned antibacterial hydrogel with high antibacterial properties is used in the preparation of flexible biosensors.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects: This invention discloses a method for preparing a highly antibacterial antifreeze hydrogel. The method employs a one-pot polymerization process, in which phytic acid (PA), [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SBMA), N-[tris(hydroxymethyl)methyl]acrylamide (THMA), and acrylamide (AM) undergo free radical polymerization under the action of an initiator and a crosslinking agent. PA is a key component; its six phosphate groups act as hydrogen bond donors, forming numerous hydrogen bonds with water molecules, effectively preventing water evaporation and crystallization, thus endowing the hydrogel with excellent antifreeze and water-locking capabilities. This solves the problem of hydrogel performance degradation due to water freezing at low temperatures. SBMA, as an amphoteric monomer, has a unique cationic and anionic structure that may form a special charge distribution on the hydrogel surface, interfering with bacterial attachment and growth, thereby exerting an antibacterial effect. Simultaneously, the H+ ions released from PA... + It may also influence the bacterial survival environment to some extent, synergistically enhancing the antibacterial effect. Furthermore, the preparation process is carried out under mild conditions, requiring no high temperature or high pressure, making it safe, environmentally friendly, and low-cost, suitable for mass production. The resulting antifreeze hydrogel not only possesses rapid gelation characteristics but also exhibits high ionic conductivity, maintaining a certain level of conductivity even at extreme low temperatures of -55℃, and can stably monitor human electrocardiograms as a sensor. This indicates that the hydrogel can normally exert its conductivity, flexibility, and adhesion properties under harsh environments such as low temperatures, successfully achieving a balance between antibacterial and antifreeze properties, opening up broad prospects for the application of hydrogels in wound management and intelligent monitoring in complex environments.

[0018] Furthermore, based on mass parts, the ratio of water to glycerol in the binary solvent of water and glycerol is (250~50):(50~250). Glycerol has a low freezing point, and this ratio range can effectively adjust the freezing point of the solvent system, preventing the water in the hydrogel from freezing at low temperatures and ensuring its antifreeze performance. At the same time, a suitable ratio ensures that the hydrogel has good flexibility and mechanical properties, avoiding excessive hardness due to too much glycerol or insufficient antifreeze due to too little glycerol. By adjusting the water and glycerol ratio, the antifreeze performance requirements of the hydrogel in different low-temperature environments can be met, expanding its application range.

[0019] Furthermore, based on mass parts, the ratio of SBMA, THMA, and AM is (45~65):(23~40):(15~20). SBMA, as an amphoteric monomer, can form dipole-dipole interactions and hydrogen bonds, enhancing the polymer network; THMA and AM participate in the polymerization reaction, contributing to the construction of a stable polymer structure. This ratio allows each component to fully exert its synergistic effect, improving the hydrogel's antibacterial properties, antifreeze properties, and mechanical properties. The appropriate ratio range ensures that the hydrogel's performance remains relatively stable across different batches, improving product quality consistency.

[0020] Furthermore, in step S2, based on mass parts, the ratio of the PA solution to water in the binary solvent is (50~200):(100~250). The six phosphate groups in PA act as hydrogen bond donors, combining with water molecules to form hydrogen bonds, preventing water evaporation and crystallization, thus endowing the hydrogel with antifreeze and water-locking capabilities. Simultaneously, the H+ ions from the ionization of PA... + This provides ionic conductivity to the hydrogel. This ratio allows for precise control of the PA content in the hydrogel, balancing antifreeze properties and ionic conductivity, enabling the hydrogel to effectively resist freezing at low temperatures while maintaining high conductivity.

[0021] Furthermore, in step S2, the ratio of initiator to crosslinker is (1~3):(3~1) by mass. The initiator initiates the free radical polymerization reaction, while the crosslinker forms a crosslinked structure between the polymer molecular chains, enhancing the mechanical properties of the hydrogel. A suitable ratio ensures the smooth progress of the polymerization reaction, forming a uniform and stable polymer network, and avoids excessively vigorous reactions due to too much initiator or excessively hard hydrogels due to too much crosslinker. A stable ratio helps obtain hydrogel products with consistent performance under different preparation conditions, reducing batch-to-batch variations.

[0022] Furthermore, in step S3, the free radical polymerization reaction is carried out at a temperature of 30–100°C for 2–10 hours. Appropriate temperature and time ranges ensure the polymerization reaction proceeds fully, allowing the polymer chains to reach suitable lengths and crosslinking densities. Excessively high temperatures may lead to overly vigorous reactions and side reactions; excessively low temperatures result in slow reaction rates, affecting production efficiency. Too short a time leads to incomplete polymerization; too long a time may result in energy waste and decreased product performance. Precise control of reaction conditions helps obtain hydrogel products with stable performance in different batches, improving product quality and reliability. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram illustrating the multifunctional properties of hydrogels. Figure 2 The following are DSC curves of the hydrogels prepared in Comparative Example 1, Example 1, and Example 3 of this invention; Figure 3 The conductivity values ​​are those of the hydrogels prepared in the comparative examples and embodiments of the present invention, wherein (a) is the conductivity of the hydrogels prepared in comparative examples 1 and embodiments 1-3 of the present invention at 25°C; and (b) is the conductivity of the hydrogels prepared in embodiment 4 of the present invention at different temperatures. Figure 4 The figures show the water retention rate tracking curves of the hydrogels prepared in the comparative examples and embodiments of the present invention, wherein (a) is the water retention rate tracking curve of the hydrogels prepared in Comparative Example 1, Example 1 and Example 3 of the present invention after 14 days; and (b) is the water retention rate tracking curve of the hydrogel prepared in Example 4 of the present invention at different temperatures after 14 days. Figure 5 The electrical conductivity and tensile properties of the hydrogels prepared in Comparative Example 1 and Example 3 of the present invention are shown, wherein (a) shows the electrical conductivity of the hydrogels prepared in Comparative Example 1 and Example 3 of the present invention at low temperatures (-25°C and -45°C); (b) shows the tensile properties of the hydrogels prepared in Comparative Example 1 and Example 3 of the present invention at -25°C; and (c) shows the tensile properties of the hydrogels prepared in Comparative Example 1 and Example 3 of the present invention at -45°C. Figure 6 The antibacterial properties of the hydrogels prepared in Comparative Example 1 and Examples 1-3 of this invention are shown. Figure 7 The adhesion of the hydrogel prepared in Example 4 of the present invention is shown in (a) and (b) shows the adhesion of the hydrogel prepared in Example 4 to pigskin at different temperatures. Figure 8 The images show the electrocardiogram (ECG) results of the hydrogel prepared in Example 4 of this invention, where (a) is a detailed ECG test image; (b) shows the ECG monitoring of different human behaviors using the hydrogel prepared in Example 4 of this invention as a cardiac patch; and (c) shows the ECG monitoring of different human behaviors using the hydrogel prepared in Example 4 of this invention as a cardiac patch after being exposed to -45°C for 14 days. Detailed Implementation

[0025] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0026] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0027] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0028] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0029] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0030] This invention provides a method for preparing an antifreeze hydrogel with high ionic conductivity, comprising the following steps: S1: N-[tris(hydroxymethyl)methyl]acrylamide (THMA), acrylamide (AM), and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SBMA) are dissolved in a mixed solvent of water and glycerol and stirred to disperse, forming suspension A; In the binary solvent of water and glycerol (GL), the ratio of water to glycerol is (250~50):(50~250) by mass parts, and more preferably, the ratio of water to glycerol is (200~50):50 by mass parts.

[0031] Wherein, the ratio of SBMA, THMA and AM by mass parts is (45~65):(23~40):(15~20), preferably, the ratio of SBMA, THMA and AM by mass parts is 50:30:17.

[0032] S2: Add phytic acid (PA) solution, initiator and crosslinking agent to the suspension A, stir evenly to obtain precursor fluid; The ratio of the PA solution to water in the binary solvent is (50~200):(100~250) by mass.

[0033] In step S2, the ratio of the initiator to the crosslinking agent is (1~3):(3~1) by mass parts. Preferably, the ratio of the initiator to the crosslinking agent is 2:1.5.

[0034] The initiator is at least one selected from ammonium persulfate, potassium persulfate, azobisisobutylamidine hydrochloride, azobisisobutylimidazoline hydrochloride, azobiscyanopentanoic acid, and azobisisopropylimidazoline.

[0035] In step S2, the crosslinking agent is at least one of polyethylene glycol diglycidyl ether, N,N'-methylenebisacrylamide, hydrazine peroxide, diallyl phthalate, divinylbenzene, diisocyanate, dicumyl peroxide, di-tert-butyl peroxide, and styrene.

[0036] S3: The precursor fluid undergoes a free radical polymerization reaction to obtain the highly ionicly conductive antifreeze hydrogel, which can be represented as STAPG.

[0037] The free radical polymerization reaction is carried out at a temperature of 30~100℃ for 2~10h.

[0038] This invention also discloses an antifreeze hydrogel with high ionic conductivity prepared by the above method. The optimal hydrogel shows no crystallization peak at -90℃ in DSC, has a conductivity of 0.47~3.60 S / m, an adhesion strength of 5.35~23.11 KPa, and a water holding capacity of 39.2%~65.5%.

[0039] This invention also discloses the application of the aforementioned highly ionicly conductive antifreeze hydrogel in the fabrication of a flexible biosensor. This flexible biosensor enables the monitoring of a patient's electrocardiogram.

[0040] This invention employs a one-pot method to radically polymerize phytic acid (PA), [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide (SBMA), N-[tris(hydroxymethyl)methyl]acrylamide (THMA), and acrylamide (AM) under the influence of an initiator and a crosslinking agent. The six phosphate groups in polyPA act as hydrogen bond donors, forming numerous hydrogen bonds with water molecules, effectively preventing water evaporation and crystallization, thus endowing the hydrogel with antifreeze and water-locking capabilities. Furthermore, PA can ionize a large amount of H+ in aqueous solution. + This provides high ionic conductivity to the hydrogel. Flexible biosensors made from antifreeze hydrogels have broad application prospects in intelligent monitoring. Furthermore, this invention uses zwitterionic [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide (SBMA), reactive monomers N-[tris(hydroxymethyl)methyl]acrylamide (THMA) and AM as reactive monomers, which can form dipole-dipole interactions and hydrogen bonding to enhance the polymer network. Polyethylene glycol diglycidyl ether (PEGDE) is used as a crosslinking agent. The high ionic conductivity antifreeze hydrogel prepared by free radical polymerization exhibits excellent conductivity and antifreeze properties, successfully solving the problem of not being able to simultaneously achieve conductivity and antifreeze properties.

[0041] like Figure 1 As shown, this invention discloses a method for preparing a highly ionicly conductive antifreeze hydrogel. The method employs a one-pot process, adding phytic acid (PA) to a mixed solution of [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide (SBMA), N-[tris(hydroxymethyl)methyl]acrylamide (THMA), and acrylamide (AM), followed by free radical polymerization under the influence of an initiator and a crosslinking agent. The six phosphate groups in PA act as hydrogen bond donors, forming numerous hydrogen bonds with water molecules, effectively preventing water evaporation and crystallization, thus endowing the hydrogel with antifreeze and water-locking capabilities. Furthermore, PA can ionize a large amount of H+ in aqueous solution. + The cations and anions in SBMA promote the transport of hydrogen ions along the backbone. This combined effect gives the STAPG hydrogel high conductivity (3.60 S / m). Even at -55°C, the conductivity of the STAPG hydrogel reaches 0.51 S / m. As a wearable sensor, the hydrogel can stably monitor human electrocardiograms. This hydrogel has broad application prospects in complex environments.

[0042] The material preparation process of this invention is carried out under mild reaction conditions, without the need for high temperature and high pressure, making it safe, environmentally friendly, and low-cost, suitable for mass production. The prepared antifreeze hydrogel exhibits rapid gelation and high ionic conductivity, making it suitable for wound management and intelligent monitoring in complex environments, and easy to use. The resulting sensor possesses good conductivity and flexibility. Based on multiple phosphate groups in PA, the designed antifreeze hydrogel exhibits ultra-low temperature antifreeze properties, water retention, and high ionic conductivity, effectively maintaining conductivity, flexibility, and adhesion properties even in harsh environments such as low temperatures. As a sensor, the antifreeze hydrogel can monitor human electrocardiograms, showing great potential in the field of intelligent monitoring.

[0043] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0044] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0045] Comparative Example 1 A method for preparing a highly antibacterial antifreeze hydrogel includes the following steps: First, 50 parts of SBMA, 30 parts of N-[tris(hydroxymethyl)methyl]acrylamide (THMA) and 17 parts of AM were added to a mixed solvent of 50 parts of glycerol and 250 parts of deionized water, and a uniform suspension A was obtained by magnetic stirring. Then, 2 parts of initiator ammonium persulfate (APS) and 1.5 parts of MBA were added to suspension A, and the mixture was stirred while adding the reagents to obtain a homogeneous precursor solution B. Finally, precursor solution B was transferred to a glass plate mold and reacted at 30°C for 2 h to allow free radical polymerization, resulting in an antifreeze hydrogel. This hydrogel is designated STAP0G. 0.5 .

[0046] Example 1 A method for preparing a highly antibacterial antifreeze hydrogel includes the following steps: First, 50 parts of SBMA, 30 parts of N-[tris(hydroxymethyl)methyl]acrylamide (THMA) and 17 parts of AM were added to a mixed solvent of 50 parts of glycerol and 200 parts of deionized water, and a uniform suspension A was obtained by magnetic stirring. Then, 50 parts of PA solution, 2 parts of initiator ammonium persulfate (APS) and 1.5 parts of MBA were added to suspension A. The mixture was stirred while adding the reagents to obtain a homogeneous precursor solution B. Finally, precursor solution B was transferred to a glass plate mold and reacted at 50°C for 5 h to allow free radical polymerization, resulting in an antifreeze hydrogel. This hydrogel is designated STAP. 0.5 G 0.5 .

[0047] Example 2 First, 50 parts of SBMA, 30 parts of N-[tris(hydroxymethyl)methyl]acrylamide (THMA) and 17 parts of AM were added to a mixed solvent of 50 parts of glycerol and 150 parts of deionized water, and a uniform suspension A was obtained by magnetic stirring. Then, 100 parts of PA solution, 2 parts of initiator ammonium persulfate (APS) and 1.5 parts of MBA were added to suspension A. The mixture was stirred while adding the reagents to obtain a homogeneous precursor solution B. Finally, precursor solution B was transferred to a glass plate mold and reacted at 100°C for 10 h to allow free radical polymerization, resulting in an antifreeze hydrogel. This hydrogel is designated STAP. 1.0 G 0.5 .

[0048] Example 3 First, 50 parts of SBMA, 30 parts of N-[tris(hydroxymethyl)methyl]acrylamide (THMA) and 17 parts of AM were added to a mixed solvent of 50 parts of glycerol and 100 parts of deionized water, and a uniform suspension A was obtained by magnetic stirring. Then, 150 parts of PA solution, 2 parts of initiator ammonium persulfate (APS) and 1.5 parts of MBA were added to suspension A. The mixture was stirred while adding the reagents to obtain a homogeneous precursor solution B. Finally, precursor solution B was transferred to a glass plate mold and reacted at 50°C for 4 h to allow free radical polymerization, resulting in an antifreeze hydrogel. This hydrogel is designated STAP. 1.5 G 0.5 .

[0049] Example 4 First, 50 parts of SBMA, 30 parts of N-[tris(hydroxymethyl)methyl]acrylamide (THMA) and 17 parts of AM were added to a mixed solvent of 50 parts of glycerol and 50 parts of deionized water, and a uniform suspension A was obtained by magnetic stirring. Then, 200 parts of PA solution, 2 parts of initiator ammonium persulfate (APS) and 1.5 parts of MBA were added to suspension A. The mixture was stirred while adding the reagents to obtain a homogeneous precursor solution B. Finally, precursor solution B was transferred to a glass plate mold and reacted at 100°C for 10 h to allow free radical polymerization, resulting in an antifreeze hydrogel. This hydrogel is designated STAP. 2.0 G 0.5 .

[0050] Table 1 shows the performance test results of the hydrogels prepared in Comparative Example 1 and Examples 1-4 of this invention, specifically: Table 1 Summary of Performance of Different Samples

[0051] Figure 2 The figures show the DSC curves of the hydrogels prepared in Comparative Example 1, Example 1, and Example 3 of this invention; as can be seen from the figures, no crystallization peaks were observed in the hydrogels at -90°C.

[0052] Figure 3 The figures show the electrical conductivity of the hydrogels prepared in the comparative examples and embodiments of the present invention. (a) shows the electrical conductivity of the hydrogels prepared in Comparative Example 1 and Examples 1-3 at 25°C; (b) shows the electrical conductivity of the hydrogel prepared in Example 4 at different temperatures. As can be seen from the figure, the hydrogel still has an electrical conductivity of 0.51 S / m at -55°C. Figure 4 The figures show the water holding capacity tracking curves of the hydrogels prepared in the comparative examples and embodiments of the present invention. (a) shows the water holding capacity tracking curves of the hydrogels prepared in Comparative Example 1, Example 1 and Example 3 of the present invention after 14 days; (b) shows the water holding capacity tracking curves of the hydrogel prepared in Example 4 of the present invention at different temperatures after 14 days. As can be seen from the figure, the hydrogel has a water holding capacity of 60% after being exposed to 25°C for 14 days. Figure 5 The figures show the electrical conductivity and tensile properties of the hydrogels prepared in Comparative Example 1 and Example 3 of the present invention. (a) shows the electrical conductivity of the hydrogels prepared in Comparative Example 1 and Example 3 of the present invention at low temperatures (-25°C and -45°C); (b) shows the tensile properties of the hydrogels prepared in Comparative Example 1 and Example 3 of the present invention at -25°C; and (c) shows the tensile properties of the hydrogels prepared in Comparative Example 1 and Example 3 of the present invention at -45°C. As can be seen from the figures, the antifreeze hydrogel can normally exhibit tensile and electrical conductivity properties at low temperatures. Figure 6 The figure shows the antibacterial properties of the hydrogels prepared in Comparative Example 1 and Examples 1-3 of the present invention. As can be seen from the figure, the hydrogels have good antibacterial properties. Figure 7 The figure shows the adhesion of the hydrogel prepared in Example 4 of the present invention. (a) shows the adhesion of the hydrogel prepared in Example 4 to pigskin at different temperatures; (b) shows the adhesion of the hydrogel prepared in Example 4 to different materials at different temperatures. As can be seen from the figure, the antifreeze hydrogel can adhere normally to tissues at low temperatures. Figure 8 The figures show the electrocardiogram (ECG) results of the hydrogel prepared in Example 4 of this invention. (a) is a detailed ECG test diagram; (b) shows the ECG monitoring of different human behaviors using the hydrogel prepared in Example 4 of this invention as a cardiac patch; and (c) shows the ECG monitoring of different human behaviors using the hydrogel prepared in Example 4 of this invention as a cardiac patch after being exposed to -45°C for 14 days. As can be seen from the figures, the antifreeze hydrogel can still successfully monitor the ECG under different human behaviors after being exposed to -45°C for 14 days.

[0053] Example 5 A method for preparing a highly ionicly conductive antifreeze hydrogel includes the following steps: S1: [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide (SBMA), N-[tris(hydroxymethyl)methyl]acrylamide (THMA), and acrylamide (AM) are dissolved in a mixed solvent of water and glycerol in a ratio of 45:23:15, wherein the ratio of water to glycerol is 250:50 by mass. The mixture is stirred and dispersed to form suspension A. S2: Add phytic acid (PA) solution, azobisisobutylamidine hydrochloride, and N,N'-methylenebisacrylamide to the suspension A, and stir until homogeneous to obtain the precursor solution; wherein, by mass parts, the ratio of PA solution to water in the binary solvent is 50:100. By mass parts, the ratio of initiator to crosslinking agent is 1:3.

[0054] S3: The precursor fluid is subjected to a free radical polymerization reaction at 30°C for 10 hours to obtain the highly ionicly conductive antifreeze hydrogel, which can be represented as STAPG.

[0055] The hydrogel prepared in this embodiment has an electrical conductivity of 0.49 S / m, an adhesion strength of 5.55 KPa, and a water holding capacity of 40.2%.

[0056] Example 6 A method for preparing a highly ionicly conductive antifreeze hydrogel includes the following steps: S1: [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide (SBMA), N-[tris(hydroxymethyl)methyl]acrylamide (THMA), and acrylamide (AM) are dissolved in a mixed solvent of water and glycerol in a ratio of 65:40:20 by mass, wherein the ratio of water to glycerol is 50:250 by mass. The mixture is stirred and dispersed to form suspension A. S2: Add phytic acid (PA) solution, initiator azodicyanovalerate, and crosslinking agent diisocyanate to the suspension A, and stir until homogeneous to obtain the precursor fluid; wherein, by mass parts, the ratio of PA solution to water in the binary solvent is 200:250. By mass parts, the ratio of initiator to crosslinking agent is 3:1.

[0057] S3: The precursor fluid is subjected to a free radical polymerization reaction at 100°C for 2 hours to obtain the highly ionicly conductive antifreeze hydrogel, which can be represented as STAPG.

[0058] The hydrogel prepared in this embodiment has an electrical conductivity of 3.55 S / m, an adhesion strength of 23.00 KPa, and a water holding capacity of 65.3%.

[0059] Example 7 A method for preparing a highly ionicly conductive antifreeze hydrogel includes the following steps: S1: [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide (SBMA), N-[tris(hydroxymethyl)methyl]acrylamide (THMA), and acrylamide (AM) are dissolved in a mixed solvent of water and glycerol in a ratio of 55:35:18 by mass, wherein the ratio of water to glycerol by mass is 100:150. The mixture is stirred and dispersed to form suspension A. S2: Add phytic acid (PA) solution, initiator azobisisopropylimidazoline, and crosslinking agent di-tert-butyl peroxide to the suspension A, and stir until homogeneous to obtain the precursor solution; wherein, by mass parts, the ratio of PA solution to water in the binary solvent is 150:150. By mass parts, the ratio of initiator to crosslinking agent is 2:2.

[0060] S3: The precursor fluid is subjected to a free radical polymerization reaction at 80°C for 7 hours to obtain the highly ionicly conductive antifreeze hydrogel, which can be represented as STAPG.

[0061] The hydrogel prepared in this embodiment has an electrical conductivity of 2.16 S / m, an adhesion strength of 14.17 KPa, and a water holding capacity of 45.5%.

[0062] In summary, this invention represents the first synthesis of a highly antibacterial antifreeze hydrogel, along with its preparation method and applications. Its advantages lie in the polymer system, where PA containing negative phosphate ions not only binds to AM chains via electrostatic interactions but also forms numerous hydrogen bonds with covalently cross-linked AM and THMA chains. This endows the STAPG hydrogel with mechanical properties. Similarly, the numerous hydroxyl groups in PA and glycerol (GL) also form abundant hydrogen bonds with water molecules, which reduces the bonding between water molecules, effectively preventing water crystallization and evaporation. Impressively, PA can release a large amount of H₂O in the GL / H₂O binary solvent. + SBMA, with its special structure, has quaternary ammonium salt positive ions. The synergistic effect of the two can combine with the bacterial membrane through electrostatic interaction, giving the hydrogel good antibacterial properties. It can be used in wearable strain sensor devices that can safely monitor human life signals in complex environments.

[0063] This invention discloses a method for preparing a highly antibacterial antifreeze hydrogel. The method employs a one-pot polymerization process, in which PA solution, [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide (SBMA), N-[tris(hydroxymethyl)methyl]acrylamide (THMA), and acrylamide (AM) are subjected to free radical polymerization under the initiator and crosslinking agent. This invention solves the problem of existing hydrogel sensors being unable to simultaneously possess both antifreeze and antibacterial properties, enabling its wide application in the field of health monitoring.

[0064] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a high-antibacterial, freeze-resistant hydrogel, characterized by, The method comprises the following steps: S1: dissolving THMA, AM and SBMA in a binary solvent of water and glycerol, stirring and dispersing to form a suspension A; S2: adding a PA solution, an initiator and a crosslinking agent to the suspension A, stirring to obtain a precursor liquid; S3: allowing the precursor liquid to undergo a radical polymerization reaction to obtain the high-ionic-conductivity anti-freezing hydrogel.

2. The method for preparing a highly antibacterial antifreeze hydrogel according to claim 1, characterized in that, According to the mass fraction, the ratio of water to glycerol in the binary solvent of water and glycerol is (250-50):(50-250).

3. The method for preparing a highly antibacterial antifreeze hydrogel according to claim 1, characterized in that, According to the mass fraction, the ratio of SBMA, THMA and AM is (45-65):(23-40):(15-20).

4. The method for preparing a highly antibacterial antifreeze hydrogel according to claim 1, characterized in that, According to the mass fraction, in step S2, the ratio of the PA solution to water in the binary solvent is (50-200):(100-250).

5. The method for preparing a highly antibacterial antifreeze hydrogel according to claim 1, characterized in that, According to the mass fraction, in step S2, the ratio of the initiator to the crosslinking agent is (1-3):(3-1).

6. The method for preparing a highly antibacterial antifreeze hydrogel according to claim 1, characterized in that, In step S2, the initiator is at least one of ammonium persulfate, potassium persulfate, azobis diisobutyl amidine hydrochloride, azobis diisobutyl imidazole hydrochloride, azobis dicyanopentanoic acid and azobis diisopropyl imidazole.

7. The method for preparing a highly antibacterial antifreeze hydrogel according to claim 1, characterized in that, In step S2, the crosslinking agent is at least one of polyethylene glycol diglycidyl ether, N,N'-methylene bisacrylamide, peroxide hydrazine, diallyl phthalate, divinyl benzene, diisocyanate, dicumyl peroxide, di-tert-butyl peroxide and styrene.

8. The method for preparing a highly antibacterial antifreeze hydrogel according to claim 1, characterized in that, In step S3, the temperature of the radical polymerization reaction is 30-100℃, and the time is 2-10h.

9. A high-antimicrobial, freeze resistant hydrogel, characterized in that, The anti-freezing hydrogel has an electrical conductivity of 0.47-3.60 S / m, an adhesive strength of 5.35-23.11 KPa and a water retention rate of 39.2%-65.5%.

10. Use of the high-antibacterial anti-freezing hydrogel in claim 9 in the preparation of a flexible biosensor.

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