Thermally stable antibacterial hydrogel and preparation method and application thereof

Abstract

This invention discloses a heat-stable antibacterial hydrogel, its preparation method, and its applications, belonging to the field of functional polymer materials. To further enhance the stability and enrich the functions of the hydrogel, this invention provides a heat-stable antibacterial hydrogel by crosslinking electro-oxidized tea polyphenols with a protein-based hydrogel. The preparation method of the electro-oxidized tea polyphenols involves dissolving tea polyphenols in a phosphate buffer or sodium sulfate solution and placing it at the anode of a power source, using the phosphate buffer or sodium sulfate solution as the cathode, and using a 33% w / v agarose gel containing potassium chloride as the salt bridge. A voltage of 2-10V is applied to the entire system at room temperature to obtain the electro-oxidized tea polyphenols. The obtained hydrogel not only exhibits significantly enhanced thermal stability and a slower degradation rate but is also environmentally friendly and possesses significant antibacterial effects, making it more promising and valuable for applications in tissue engineering, medicine, and other fields.

Description

Technical Field

[0001] This invention belongs to the field of functional polymer materials, specifically relating to a heat-stable antibacterial hydrogel, its preparation method, and its application. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] The skin, the largest organ in the human body, protects various tissues and organs from physical, mechanical, chemical, and pathogenic microbial attacks. Because the skin is in direct contact with the external environment, it is susceptible to damage from external forces, resulting in skin wounds. During the healing process, these wounds are vulnerable to infection by various microorganisms, hindering healing and, in severe cases, even endangering the patient's life. Compared to traditional gauze, hydrogel dressings provide a moist environment for the wound, avoiding secondary damage from dressing changes and promoting healing. However, the moist environment of hydrogel dressings also provides favorable growth conditions for pathogenic microorganisms; therefore, developing antibacterial hydrogel dressings would be more beneficial for practical applications.

[0004] Protein-based hydrogels, such as collagen and collagen-like proteins, which use proteins as the basic building blocks of hydrogel networks, have shown promising applications in medical fields such as tissue engineering and skin regeneration due to their excellent biocompatibility, biodegradability, and low cytotoxicity. However, these hydrogels have high water content, making their gel structure more susceptible to damage, resulting in poor stability and rapid degradation. Although cross-linking with chemical reagents such as glutaraldehyde and EDC-NHS can improve the stability of hydrogels, these chemical cross-linking agents are often cytotoxic and difficult to remove, and also render the hydrogels non-biodegradable.

[0005] Tea polyphenols, abbreviated as TP, are a class of polyhydroxy compounds found in tea leaves. Their main chemical components are complexes of catechins (flavanols), flavonoids and flavonols, anthocyanins, phenolic acids and condensed phenolic acids, and polymeric phenols. Numerous studies have demonstrated that tea polyphenols not only have no toxic side effects but also possess various physiological and pharmacological activities, including antioxidant, free radical scavenging, antibacterial, and immune-enhancing effects. Patent CN 114702692A discloses a method of improving hydrogel stability by cross-linking flavonoids (tea polyphenols) with protein-based hydrogels; however, the stability of the obtained hydrogels still needs further improvement. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a heat-stable antibacterial hydrogel, its preparation method, and its application. The hydrogel provided by the present invention employs a common chemical cross-linking method, utilizing electro-oxidation of tea polyphenols to enhance hydrogel stability and slow down degradation rates. The preparation method is safe, environmentally friendly, and has no toxic side effects, while also exhibiting excellent antibacterial effects.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows:

[0008] In a first aspect, the present invention provides a method for preparing a heat-stable antibacterial hydrogel, comprising the following steps: crosslinking electro-oxidized tea polyphenols with a protein hydrogel;

[0009] The method for preparing electro-oxidized tea polyphenols is as follows: dissolve tea polyphenols in phosphate buffer or sodium sulfate solution and place it at the anode of a power source. Use phosphate buffer or sodium sulfate solution as the cathode of the power source. The salt bridge is made of 33% w / v agar gel containing potassium chloride. Apply a voltage of 2-10V to the entire system at room temperature for 1-5 hours to obtain electro-oxidized tea polyphenols.

[0010] This invention utilizes electro-oxidized tea polyphenols as a cross-linking agent to improve the stability of hydrogels. Tea polyphenols contain a large number of catechin groups. This invention rapidly oxidizes catechin groups to quinones through electro-oxidation. Under the mediation of quinones, strong and irreversible covalent cross-links can be formed between the oxidized catechin groups and between the catechin groups and the amino groups on the surface of the hydrogel or protein, thereby greatly improving the stability of the hydrogel.

[0011] Preferably, the phosphate buffer solution has a concentration of 10 mM and a pH of 7.4.

[0012] Preferably, the sodium sulfate solution has a concentration of 10 mM and a pH of 7.

[0013] Preferably, the concentration of potassium chloride is 3M.

[0014] Preferably, the concentration of tea polyphenols in the solution is 10–100 mg / ml. -1 .

[0015] Preferably, the preparation method is as follows: collagen-like protein is mixed with 0.05-0.2M acid to prepare an acid solution of 25-50 mg / mL, then electro-oxidized tea polyphenols are added, and the pH is adjusted to 6-8 with 0.05-2M NaOH solution, and then allowed to stand at room temperature for 5-10 minutes.

[0016] The final concentration of electro-oxidized tea polyphenols is 0.1% to 1% of the total hydrogel.

[0017] The amino acid sequence and preparation method of the collagen-like protein are described in patent CN 115724924A or patent CN114262368A.

[0018] More preferably, the acid is one of hydrochloric acid, malic acid, acetic acid, citric acid, and vitamin C.

[0019] Preferably, the preparation method is as follows: soaking collagen hydrogel in an aqueous solution of electro-oxidized tea polyphenols with a concentration of 0.1% to 1% for 1-3 days.

[0020] More preferably, the preparation method of the collagen hydrogel is as follows: collagen is mixed with 0.05-0.2M acid to prepare an acid solution of 5-15 mg / mL, and then the pH is adjusted to 6-8 with 0.05-2M NaOH solution and allowed to stand at room temperature for 5-10 min.

[0021] More preferably, the acid is one of hydrochloric acid, malic acid, acetic acid, citric acid, and vitamin C.

[0022] In a second aspect, the present invention provides a heat-stable antibacterial hydrogel prepared by the above preparation method.

[0023] The heat-stable antibacterial hydrogel prepared by this invention exhibits excellent antibacterial effects and thermal stability, slow degradation rate, and is safe, environmentally friendly, and free of any toxic side effects. Therefore, a third aspect of this invention provides the application of the above-mentioned heat-stable antibacterial hydrogel in antibacterial products.

[0024] The antibacterial product inhibits Escherichia coli and Staphylococcus aureus.

[0025] The beneficial effects of this invention are as follows:

[0026] This invention marks the first successful synthesis of a hydrogel by combining collagen-like substances, collagen, and electro-oxidized tea polyphenols. Compared to simple hydrogels, the thermally stable antibacterial hydrogel prepared using this method not only achieves the goals of enhancing hydrogel stability and slowing down degradation through conventional chemical cross-linking methods, but more importantly, it is safer, more environmentally friendly, and free of any toxic side effects. Furthermore, it endows the hydrogel with previously unavailable properties such as antibacterial activity.

[0027] Compared with the tea polyphenol hydrogel prepared by patent CN 114702692A, the hydrogel prepared by the present invention has significantly improved thermal stability, significantly slowed down degradation rate, and extended service life of hydrogel.

[0028] In summary, the novel heat-stable antibacterial hydrogel prepared using the method of this invention not only has significantly enhanced heat stability and slowed degradation rate, but is also environmentally friendly and has significant antibacterial effects, which makes it more valuable and promising for applications in tissue engineering, medicine and other fields. Attached Figure Description

[0029] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0030] Figure 1 This is a diagram of the apparatus used in the electro-oxidation process for preparing tea polyphenols in this embodiment of the invention;

[0031] Figure 2 This is a comparative graph showing the stability of the heat-stable antibacterial hydrogel prepared in Example 1 of the present invention and the tea polyphenol collagen hydrogel prepared in Comparative Example 1; wherein, A is the tea polyphenol collagen hydrogel prepared in Comparative Example 1, B is the electro-oxidized tea polyphenol collagen hydrogel prepared in Example 1, and C is the degradation rate curve of the tea polyphenol collagen hydrogel of Comparative Example 1 and the electro-oxidized tea polyphenol collagen hydrogel of Example 1.

[0032] Figure 3 A comparative graph showing the stability of the heat-stable antibacterial hydrogel prepared in Example 1 of the present invention and the air-oxidized collagen hydrogel prepared in Comparative Example 2.

[0033] Figure 4 This diagram illustrates the inhibition of Escherichia coli and Staphylococcus aureus growth by the heat-stable antibacterial hydrogel prepared in Example 1 of this invention. Detailed Implementation

[0034] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0035] The electro-oxidized tea polyphenols involved in the following examples or comparative examples are obtained by electro-oxidizing tea polyphenols. The electro-oxidation is carried out in an electrolytic cell, with a solution containing tea polyphenols as the anolyte, and the catechin groups in the tea polyphenols are oxidized to quinones.

[0036] The amino acid sequences and preparation methods of the collagen-like proteins used in the following examples or comparative examples are referenced from patent CN115724924A or patent CN 114262368A.

[0037] Example 1

[0038] A method for preparing a heat-stable antibacterial hydrogel includes the following steps:

[0039] (1) Preparation of electro-oxidized tea polyphenols

[0040] Add tea polyphenols (55mg / ml) -1 The solution was dissolved in phosphate buffer (10 mM, pH 7.4) and placed at the anode of the power supply; the phosphate buffer (10 mM, pH 7.4) was used as the cathode of the power supply. The salt bridge was made of 33% w / v agarose gel containing KCl (3 M). A voltage of 6 V was then applied to the entire system, and the reaction was allowed to proceed for 1 h. All experiments were conducted at room temperature.

[0041] (2) Mix the collagen-like protein with 0.05–0.2 M hydrochloric acid to prepare an acid solution of 25–50 mg / mL. Then add the phosphate buffer solution containing electro-oxidized tea polyphenols prepared in step (1). Adjust the pH to 6–8 with 0.05–2 M NaOH solution and let it stand at room temperature for 5–10 minutes to form a hydrogel. Note: The final concentration of electro-oxidized tea polyphenols accounts for 1% of the total hydrogel.

[0042] The obtained hydrogel has good stability and an anti-degradation time of more than 14 days; it also has the effect of inhibiting Escherichia coli and Staphylococcus aureus.

[0043] Example 2

[0044] A method for preparing a heat-stable antibacterial hydrogel includes the following steps:

[0045] (1) Preparation of electro-oxidized tea polyphenols

[0046] Add tea polyphenols (10mg / ml) -1 The solution was dissolved in phosphate buffer (10 mM, pH 7.4) and placed at the anode of the power supply; the phosphate buffer (10 mM, pH 7.4) was used as the cathode of the power supply. The salt bridge was made of 33% w / v agarose gel containing KCl (3 M). A voltage of 6 V was then applied to the entire system, and the reaction was allowed to proceed for 1 h. All experiments were conducted at room temperature.

[0047] (2) Mix the collagen-like protein with 0.05–0.2 M malic acid to prepare an acidic solution of 25–50 mg / mL. Then add the phosphate buffer solution containing electro-oxidized tea polyphenols prepared in step (1). Adjust the pH to 6–8 with 0.05–2 M NaOH solution and let it stand at room temperature for 5–10 min to form a hydrogel. Note: The final concentration of electro-oxidized tea polyphenols accounts for 0.1%–1% of the total hydrogel.

[0048] The obtained hydrogel has good stability and an anti-degradation time of more than 14 days; it also has the effect of inhibiting Escherichia coli and Staphylococcus aureus.

[0049] Example 3

[0050] A method for preparing a heat-stable antibacterial hydrogel includes the following steps:

[0051] (1) Preparation of electro-oxidized tea polyphenols

[0052] Add tea polyphenols (100mg / ml) -1 The solution was dissolved in phosphate buffer (10 mM, pH 7.4) and placed at the anode of the power supply; the phosphate buffer (10 mM, pH 7.4) was used as the cathode of the power supply. The salt bridge was made of 33% w / v agarose gel containing KCl (3 M). A voltage of 6 V was then applied to the entire system, and the reaction was allowed to proceed for 1 h. All experiments were conducted at room temperature.

[0053] (2) Mix the collagen-like protein with 0.05–0.2 M acetic acid to prepare an acidic solution of 25–50 mg / mL. Then add the phosphate buffer solution containing electro-oxidized tea polyphenols prepared in step (1). Adjust the pH to 6–8 with 0.05–2 M NaOH solution and let it stand at room temperature for 5–10 minutes to form a hydrogel. Note: The final concentration of electro-oxidized tea polyphenols accounts for 0.1%–1% of the total hydrogel.

[0054] The obtained hydrogel has good stability and an anti-degradation time of more than 14 days; it also has the effect of inhibiting Escherichia coli and Staphylococcus aureus.

[0055] Example 4

[0056] A method for preparing a heat-stable antibacterial hydrogel includes the following steps:

[0057] (1) Preparation of electro-oxidized tea polyphenols

[0058] Add tea polyphenols (55mg / ml) -1 The solution was dissolved in sodium sulfate solution (10 mM, pH = 7) and placed as the anode of the power supply; the sodium sulfate solution (10 mM, pH = 7) was used as the cathode of the power supply. The salt bridge was made of 33% w / v agarose gel containing KCl (3 M). A voltage of 6 V was then applied to the entire system, and the reaction was allowed to proceed for 1 h. All experiments were conducted at room temperature.

[0059] (2) Mix the collagen-like protein with 0.05–0.2 M citric acid to prepare an acidic solution of 25–50 mg / mL. Then add the sodium sulfate solution containing electro-oxidized tea polyphenols prepared in step (1). Adjust the pH to 6–8 with 0.05–2 M NaOH solution and let it stand at room temperature for 5–10 minutes to form a hydrogel. Note: The final concentration of electro-oxidized tea polyphenols accounts for 0.1%–1% of the total hydrogel.

[0060] The obtained hydrogel has good stability and an anti-degradation time of more than 14 days; it also has the effect of inhibiting Escherichia coli and Staphylococcus aureus.

[0061] Example 5

[0062] A method for preparing a heat-stable antibacterial hydrogel includes the following steps:

[0063] (1) Preparation of electro-oxidized tea polyphenols

[0064] Add tea polyphenols (10mg / ml) -1 The solution was dissolved in sodium sulfate solution (10 mM, pH = 7) and placed as the anode of the power supply; the sodium sulfate solution (10 mM, pH = 7) was used as the cathode of the power supply. The salt bridge was made of 33% w / v agarose gel containing KCl (3 M). A voltage of 6 V was then applied to the entire system, and the reaction was allowed to proceed for 1 h. All experiments were conducted at room temperature.

[0065] (2) Mix the collagen-like protein with 0.05–0.2 M vitamin C to prepare an acidic solution of 25–50 mg / mL. Then add the sodium sulfate solution containing electro-oxidized tea polyphenols prepared in step (1). Adjust the pH to 6–8 with 0.05–2 M NaOH solution and let it stand at room temperature for 5–10 minutes to form a hydrogel. Note: The final concentration of electro-oxidized tea polyphenols accounts for 0.1%–1% of the total hydrogel.

[0066] The obtained hydrogel has good stability and an anti-degradation time of more than 14 days; it also has the effect of inhibiting Escherichia coli and Staphylococcus aureus.

[0067] Example 6

[0068] A method for preparing a heat-stable antibacterial hydrogel includes the following steps:

[0069] Collagen is mixed with 0.05–0.2 M hydrochloric acid to prepare an acidic solution of 5–15 mg / mL. The pH is then adjusted to 6–8 with 0.05–2 M NaOH solution, and the solution is allowed to stand at room temperature for 5–10 minutes to form a hydrogel. This hydrogel is then immersed in an aqueous solution of electro-oxidized tea polyphenols (0.1%–1%) for 1–3 days.

[0070] The obtained hydrogel has good stability and an anti-degradation time of more than 14 days; it also has the effect of inhibiting Escherichia coli and Staphylococcus aureus.

[0071] Example 7

[0072] A method for preparing a heat-stable antibacterial hydrogel includes the following steps:

[0073] Collagen is mixed with 0.05–0.2 M malic acid to prepare an acidic solution of 5–15 mg / mL. The pH is then adjusted to 6–8 with 0.05–2 M NaOH solution, and the solution is allowed to stand at room temperature for 5–10 minutes to form a hydrogel. This hydrogel is then immersed in an aqueous solution of electro-oxidized tea polyphenols (0.1%–1%) for 1–3 days.

[0074] The obtained hydrogel has good stability and an anti-degradation time of more than 14 days; it also has the effect of inhibiting Escherichia coli and Staphylococcus aureus.

[0075] Example 8

[0076] A method for preparing a heat-stable antibacterial hydrogel includes the following steps:

[0077] Collagen is mixed with 0.05–0.2 M acetic acid to prepare an acidic solution of 5–15 mg / mL. The pH is then adjusted to 6–8 with 0.05–2 M NaOH solution, and the solution is allowed to stand at room temperature for 5–10 minutes to form a hydrogel. This hydrogel is then immersed in an aqueous solution of electro-oxidized tea polyphenols (0.1%–1%) for 1–3 days.

[0078] The obtained hydrogel has good stability and an anti-degradation time of more than 14 days; it also has the effect of inhibiting Escherichia coli and Staphylococcus aureus.

[0079] Example 9

[0080] A method for preparing a heat-stable antibacterial hydrogel includes the following steps:

[0081] Collagen is mixed with 0.05–0.2 M citric acid to prepare an acidic solution of 5–15 mg / mL. The pH is then adjusted to 6–8 with 0.05–2 M NaOH solution, and the solution is allowed to stand at room temperature for 5–10 minutes to form a hydrogel. This hydrogel is then immersed in an aqueous solution of electro-oxidized tea polyphenols (0.1%–1%) for 1–3 days.

[0082] The obtained hydrogel has good stability and an anti-degradation time of more than 14 days; it also has the effect of inhibiting Escherichia coli and Staphylococcus aureus.

[0083] Example 10

[0084] A method for preparing a heat-stable antibacterial hydrogel includes the following steps:

[0085] Collagen is mixed with 0.05–0.2 M vitamin C to prepare an acidic solution of 5–15 mg / mL. The pH is then adjusted to 6–8 with 0.05–2 M NaOH solution, and the solution is allowed to stand at room temperature for 5–10 minutes to form a hydrogel. This hydrogel is then immersed in an aqueous solution of electro-oxidized tea polyphenols (0.1%–1%) for 1–3 days.

[0086] The obtained hydrogel has good stability and an anti-degradation time of more than 14 days; it also has the effect of inhibiting Escherichia coli and Staphylococcus aureus.

[0087] The preparation methods of electro-oxidized tea polyphenols used in Examples 6-10 are the same as those in Example 1.

[0088] Comparative Example 1

[0089] A tea polyphenol-based collagen hydrogel is prepared in a manner different from that in Example 1, the tea polyphenols are added directly to the acid solution without electro-oxidation. The specific preparation method is as follows:

[0090] Mix collagen-like proteins with 0.05–0.2 M hydrochloric acid to prepare an acidic solution of 25–50 mg / mL. Then add tea polyphenols and adjust the pH to 6–8 with 0.05–2 M NaOH solution. Allow to stand at room temperature to form a hydrogel. Note: The final concentration of tea polyphenols is 1% of the total hydrogel.

[0091] Comparative Example 2

[0092] An air-oxidized collagen hydrogel is prepared in a manner different from that in Example 1, the tea polyphenols are oxidized by air instead of by electro-oxidation. The specific preparation method is as follows:

[0093] (1) Add tea polyphenols (55mg ml) -1 Dissolve the tea polyphenols in a phosphate buffer solution (10 mM, pH = 7.4) and let it stand at room temperature for 3 days to carry out air oxidation of tea polyphenols.

[0094] (2) Mix the collagen-like protein with 0.05–0.2 M hydrochloric acid to prepare an acid solution of 25–50 mg / mL. Then add the tea polyphenols that have been oxidized in air for 3 days in step (1). Adjust the pH to 6–8 with 0.05–2 M NaOH solution and let it stand at room temperature to form a hydrogel. Note: The final concentration of the air-oxidized tea polyphenols accounts for 1% of the total hydrogel.

[0095] Performance testing

[0096] 1. Stability testing

[0097] To test the stability of the thermally stable antibacterial hydrogel prepared in Example 1, the tea polyphenol collagen hydrogel prepared in Comparative Example 1, and the air-oxidized tea polyphenol collagen hydrogel prepared in Comparative Example 2, the electro-oxidized tea polyphenol collagen hydrogel prepared in Example 1, the tea polyphenol collagen hydrogel prepared in Comparative Example 1, and the air-oxidized tea polyphenol collagen hydrogel prepared in Comparative Example 2 were respectively immersed in PBS buffer, and the degree of hydrogel degradation was observed.

[0098] Test results as follows Figure 2 As shown. Comparison Figure 2 A, Figure 2 As can be seen from B, the electro-oxidized tea polyphenol collagen hydrogel prepared in Example 1 of this invention, compared with the tea polyphenol collagen hydrogel prepared in Comparative Example 1, shows that the hydrogel is more intact and less degraded after 14 days of soaking. Figure 2 As can be seen from C, on the 14th day of soaking, the degradation rate of the hydrogel prepared in Example 1 was less than 10%, while the degradation rate of the hydrogel prepared in Comparative Example 1 was as high as 50% or more.

[0099] like Figure 3 As shown, on the 14th day of soaking, the degradation rate of the air-oxidized tea polyphenol collagen hydrogel prepared in Comparative Example 2 reached about 30%, which was still significantly higher than that of the hydrogel prepared in Example 1. The electro-oxidation time for the tea polyphenols used in the hydrogel of Example 1 was 1 hour, while the air-oxidized time for the hydrogel of Comparative Example 2 was 3 days. From the perspective of hydrogel stability, the hydrogel prepared in Example 1 showed better stability than that prepared in Comparative Example 2. Therefore, the present invention, using electro-oxidation of tea polyphenols to prepare hydrogels, not only improves the stability of the hydrogels but also has the advantages of fast preparation speed and significant time savings.

[0100] It is evident that the electro-oxidized tea polyphenol collagen hydrogel prepared by this invention exhibits higher thermal stability, slower degradation rate, and longer service life compared to tea polyphenol collagen hydrogel and air-oxidized tea polyphenol collagen hydrogel.

[0101] (2) Antibacterial test

[0102] To test the antibacterial properties of the heat-stable antibacterial hydrogel prepared in Example 1, the electro-oxidized tea polyphenol collagen hydrogel prepared in Example 1 was co-cultured with Escherichia coli and Staphylococcus aureus, and the number of Escherichia coli or Staphylococcus aureus in the culture medium was observed.

[0103] Test results as follows Figure 4 As shown, the number of Escherichia coli and Staphylococcus aureus in the culture medium containing the electro-oxidized tea polyphenol collagen hydrogel prepared in Example 1 was lower than that in the control group, indicating that the hydrogel prepared in this invention has excellent antibacterial effect.

[0104] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a heat-stable antibacterial hydrogel, characterized in that, The steps include: cross-linking electro-oxidized tea polyphenols with protein hydrogels; The preparation method of the electro-oxidized tea polyphenol is as follows: dissolve tea polyphenol in phosphate buffer or sodium sulfate solution and place it at the anode of the power supply. Use phosphate buffer or sodium sulfate solution as the cathode of the power supply. The salt bridge is made of 33% w / v agar gel containing potassium chloride. Apply a voltage of 2-10 V to the entire system at room temperature for 1-5 h to obtain electro-oxidized tea polyphenol. Mix collagen-like substances with 0.05-0.2 M acid to prepare an acid solution of 25-50 mg / mL, then add electro-oxidized tea polyphenols, and then adjust the pH to 6-8 with 0.05-2 M NaOH solution, and let it stand at room temperature for 5-10 minutes. The final concentration of electro-oxidized tea polyphenols was 0.1% to 1% of the total hydrogel. Alternatively, the collagen hydrogel can be soaked in an electro-oxidized tea polyphenol aqueous solution with a concentration of 0.1%~1% for 1-3 days; The collagen hydrogel is prepared by mixing collagen with 0.05-0.2 M acid to make an acid solution of 5-15 mg / mL, then adjusting the pH to 6-8 with 0.05-2 M NaOH solution, and letting it stand at room temperature for 5-10 minutes.

2. The preparation method according to claim 1, characterized in that, The phosphate buffer solution has a concentration of 10 mM and a pH of 7.

4. Alternatively, the sodium sulfate solution has a concentration of 10 mM and a pH of 7; Alternatively, the concentration of potassium chloride is 3M.

3. The preparation method according to claim 1, characterized in that, The concentration of tea polyphenols in a solution is 10-100 mg / ml. -1 .

4. The preparation method according to claim 1, characterized in that, The acid is one of hydrochloric acid, malic acid, acetic acid, citric acid, and vitamin C.

5. The heat-stable antibacterial hydrogel prepared by any of the preparation methods described in claims 1-4.

6. The application of the heat-stable antibacterial hydrogel according to claim 5 in the preparation of antibacterial products; The antibacterial product inhibits Escherichia coli and Staphylococcus aureus.

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