A medical antibacterial repair hydrogel and its preparation method

Abstract

The present invention discloses a medical antibacterial repair hydrogel and its preparation method, belonging to the technical field of biomedical materials. This hydrogel is prepared by combining a mixed solution of polyvinyl alcohol and sodium carboxymethylcellulose with a modified antibacterial peptide through freeze-thaw cycles. The amino acid sequence of the modified antibacterial peptide is FLWLIPALAGAIGKLIK-NH2, which has significant antibacterial activity and can effectively inhibit the growth of Gram-negative bacteria, Gram-positive bacteria, and fungi, especially showing strong inhibitory effects on Escherichia coli, Staphylococcus aureus, and Candida albicans. In addition, the hydrogel containing the antibacterial peptide shows excellent repair effects in wound healing experiments, significantly improving the wound healing rate. Therefore, the hydrogel provided by the present invention not only has high antibacterial ability but also can promote wound repair, having broad clinical application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomedical materials, and particularly relates to a medical antibacterial repair hydrogel and a preparation method thereof. Background Art

[0002] Medical hydrogel is a hydrophilic polymer network material. Its unique physical and chemical properties, such as good biocompatibility, high water content and breathability, enable it to provide a moist microenvironment for the wound site, relieve pain caused by external stimuli and dryness, and create favorable conditions for cell migration, proliferation and tissue repair. Given the above advantages, medical hydrogels have been widely used in biomedical fields such as wound dressings, burn treatment, postoperative rehabilitation, drug delivery, and tissue engineering. It can effectively absorb wound exudate, reduce complications caused by exudate accumulation, and to a certain extent block the invasion of external pathogens, thereby alleviating the pain of patients, promoting wound healing, and improving the healing quality.

[0003] However, traditional medical hydrogels still have certain limitations in wound care, especially in the prevention and control of bacterial infections. Due to its high water content, ordinary hydrogels are prone to become a breeding ground for bacteria in a humid environment. If the growth of microorganisms cannot be effectively inhibited, it may lead to or exacerbate wound infections and delay the healing process. Therefore, developing new medical hydrogels with excellent antibacterial properties is one of the key problems that need to be solved urgently at present. Summary of the Invention

[0004] The purpose of the present invention is to provide a medical antibacterial repair hydrogel with high antibacterial performance and a preparation method thereof.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] In the first aspect, the present invention provides a preparation method of a medical antibacterial repair hydrogel, and the preparation method of the medical antibacterial repair hydrogel includes the following steps:

[0007] a) Dissolve polyvinyl alcohol in an aqueous glycerol solution to obtain a polyvinyl alcohol solution;

[0008] b) Dissolve sodium carboxymethyl cellulose in an aqueous glycerol solution to obtain a sodium carboxymethyl cellulose solution;

[0009] c) Mix the polyvinyl alcohol solution and the sodium carboxymethyl cellulose solution in a volume ratio of 1:1 to obtain a PVA / Na-CMC solution;

[0010] d) Dissolve the modified antibacterial peptide in deionized water to obtain a modified antibacterial peptide solution;

[0011] e) Mix the modified antimicrobial peptide solution with the PVA / Na-CMC solution at a volume ratio of 1:10 to obtain a PVA / Na-CMC solution containing the modified antimicrobial peptide;

[0012] f) Transfer the PVA / Na-CMC solution containing the modified antimicrobial peptide to a freezing device and freeze it for the first time to obtain a hydrogel containing the modified antimicrobial peptide;

[0013] g) Take out the hydrogel, thaw it at room temperature, and then freeze it for the second time to obtain the medical antibacterial repair hydrogel;

[0014] The amino acid sequence of the modified antimicrobial peptide is FLWLIPALAGAIGKLIK-NH2.

[0015] Preferably, the glycerol aqueous solution is a 50% glycerol aqueous solution;

[0016] The polyvinyl alcohol solution is a 10% mass concentration polyvinyl alcohol solution;

[0017] The concentration of the modified antimicrobial peptide solution is greater than or equal to 0.5 mg / mL

[0018] The sodium carboxymethyl cellulose solution is a 1% mass concentration sodium carboxymethyl cellulose solution;

[0019] The conditions for the first freezing are freezing at -20°C for 8 hours, the room temperature thawing time is 1 hour, and the conditions for the second freezing are freezing at -20°C for 8 hours.

[0020] Preferably, the concentration of the modified antimicrobial peptide solution is 0.5 mg / mL.

[0021] Preferably, the medical antibacterial inhibits Gram-negative bacteria, Gram-positive bacteria, and fungi;

[0022] The repair is for the healing repair of skin injury wounds, and the skin injury includes mechanical injury, physical injury, and chemical injury.

[0023] Preferably, the Gram-negative bacteria is Escherichia coli ATCC 25922, the Gram-positive bacteria is Staphylococcus aureus ATCC 25923, and the fungi is Candida albicans ATCC 10231.

[0024] Preferably, the skin injury is mechanical injury, and the mechanical injury is a cut injury.

[0025] In a second aspect, the present invention provides a medical antibacterial repair hydrogel, and the medical antibacterial repair hydrogel is prepared by the preparation method described above.

[0026] In a third aspect, the present invention provides the use of a modified antimicrobial peptide in the preparation of an antibacterial agent or an antibacterial hydrogel, characterized in that the amino acid sequence of the modified antimicrobial peptide is FLWLIPALAGAIGKLIK-NH2.

[0027] Preferably, the antibacterial spectrum of the antibacterial agent is Gram-negative bacteria, Gram-positive bacteria and fungi.

[0028] Preferably, the Gram-negative bacteria is Escherichia coli ATCC 25922, the Gram-positive bacteria is Staphylococcus aureus ATCC 25923, and the fungus is Candida albicans ATCC 10231.

[0029] Preferably, in the antibacterial agent or the antibacterial hydrogel, the concentration of the modified antimicrobial peptide is greater than or equal to 50 μg / mL.

[0030] Preferably, in the antibacterial agent or the antibacterial hydrogel, the concentration of the modified antimicrobial peptide is 50 μg / mL.

[0031] The present invention has the following remarkable beneficial effects:

[0032] By optimizing the amino acid sequence of the antimicrobial peptide and combining with acetylation modification, the present invention significantly improves the antibacterial activity. Specifically, the optimized antimicrobial peptide b shows significant antibacterial effects against common pathogenic microorganisms such as Escherichia coli, Staphylococcus aureus and Candida albicans. Compared with traditional antimicrobial peptides, its antibacterial efficiency is increased by more than 70%. Notably, the inhibitory effect of antimicrobial peptide b on Candida albicans has made a breakthrough, showing antibacterial activity that the original antimicrobial peptide does not possess, thus demonstrating good broad-spectrum antibacterial performance.

[0033] In addition, the hydrogel prepared by the present invention shows high antibacterial activity. In vitro antibacterial experiments show that after co-incubation with Escherichia coli and Staphylococcus aureus for 6 hours, their growth can be completely inhibited, and it shows significant inhibitory effects on Candida albicans, thus effectively inhibiting pathogenic microorganisms at the wound site and preventing the occurrence of infection.

[0034] In addition, the hydrogel containing antimicrobial peptide b (hydrogel c) prepared by the present invention shows extremely excellent effects in the mouse wound healing experiment. After 12 days of treatment, the wound healing rate of the wound treated with hydrogel c reaches 96.05%, which is much higher than that of hydrogel a (61.57%) without adding antimicrobial peptide and hydrogel b (76.86%) adding antimicrobial peptide Hylin PL. This result indicates that the hydrogel containing antimicrobial peptide b not only has significant advantages in antibacterial performance, but also can effectively promote wound healing, and has good clinical application prospects. Description of the Drawings

[0035] Figure 1In vitro antibacterial effect of hydrogel containing antibacterial peptide b

[0036] Figure 2 Repair effect of hydrogel containing antibacterial peptide b on skin wounds in mice Specific implementation manners

[0037] The present invention will be further described in detail below in conjunction with embodiments, but the implementation manners of the present invention are not limited thereto. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the technical field. The test methods without specific experimental conditions in the following embodiments usually follow the conventional experimental conditions. Unless otherwise specified, the reagents and raw materials used in the present invention can be obtained through commercial channels.

[0038] Antibacterial peptide Hylin PL belongs to a natural antibacterial peptide, which is derived from the South American tree frog, and its amino acid sequence is: FLGLIPALAGAIGNLIK, SEQ ID NO.1. It has bactericidal effects on a variety of bacteria, but the inhibitory effect is relatively weak. In order to further improve its antibacterial activity, the present invention has modified its amino acid sequence, aiming to obtain better antibacterial effects and apply it to the preparation of medical hydrogels.

[0039] Antibacterial peptide a: Replace the 5th position: I (isoleucine) with R (arginine), and the 11th position: A (alanine) with W (tryptophan), and the obtained sequence is as follows: FLGLRPALAGWIGNLIK, SEQ ID NO.2;

[0040] Antibacterial peptide b: Replace the 3rd position: G (glycine) with W (tryptophan), the 14th position: N (aspartic acid) with K (lysine), and acetylate the C-terminus. The obtained sequence is as follows: FLWLIPALAGAIGKLIK-NH2, SEQ ID NO.3;

[0041] Antibacterial peptide c: Replace the 2nd position: L (leucine) with K (lysine), the 15th position: L (leucine) with F (phenylalanine), and acetylate the C-terminus. The obtained sequence is as follows: FKGLIPALAGAIGNFIK-NH2, SEQ ID NO.4.

[0042] The above-mentioned antibacterial peptides were all synthesized on behalf of by Shanghai New Bio-Tech Co., Ltd.

[0043] Example 1

[0044] Detect the inhibition zone diameter of different antibacterial peptides by the disc diffusion method

[0045] Detection of Escherichia coli and Staphylococcus aureus

[0046] (1) Pick a single colony of activated Escherichia coli ATCC 25922 or Staphylococcus aureus ATCC 25923 respectively, inoculate it into LB liquid medium, and culture it overnight at 37°C with shaking at 120 rpm to obtain an Escherichia coli or Staphylococcus aureus suspension;

[0047] (2) Adjust the Escherichia coli or Staphylococcus aureus suspension to 1×10 8 CFU / mL, take 200 μL of the bacterial suspension and spread it on the prepared LB solid medium;

[0048] (3) Prepare solutions of antimicrobial peptides Hylin PL, a, b, and c at 50 μg / mL, filter the solutions using a 0.22 μm filter membrane to ensure the solutions are sterile;

[0049] (4) After autoclaving filter discs with a diameter of 5 mm, add the prepared 100 μL of antimicrobial peptide solution to the central area of the filter discs in portions;

[0050] (5) After standing for 1 hour, dry the drug sensitivity test paper to obtain drug sensitivity test paper loaded with antimicrobial peptides;

[0051] (6) Place the drug sensitivity test paper on the solid medium and place it in a constant temperature incubator, and culture it at 37°C for 24 h;

[0052] (7) After the culture is completed, use a vernier caliper to measure the diameter of the inhibition zone by the cross method, measure three times and take the average value, and the results are expressed as the average value ± standard deviation.

[0053] Detection of Candida albicans

[0054] (1) Pick a single colony of activated Candida albicans ATCC 10231, inoculate it into YPD liquid medium, and culture it overnight at 37°C with shaking at 120 r / min to obtain a Candida albicans suspension;

[0055] (2) Adjust the concentration of the Candida albicans suspension to 1×10 8 CFU / mL, take 200 μL of the bacterial suspension and spread it on the prepared Sabouraud solid medium;

[0056] (3) Prepare solutions of antimicrobial peptides Hylin PL, a, b, and c at 50 μg / mL, filter the solutions using a 0.22 μm filter membrane to ensure the solutions are sterile;

[0057] (4) After autoclaving filter discs with a diameter of 5 mm, add the prepared 100 μL of antimicrobial peptide solution to the central area of the filter discs in portions;

[0058] After standing for 1 hour, the drug susceptibility test paper is dried to obtain the drug susceptibility test paper loaded with antibacterial peptides;

[0059] (6) Place the drug susceptibility test paper on the Sabouraud's medium and put it into a constant temperature incubator, and culture it at 37 °C for 24 h;

[0060] (7) After the culture is completed, use a vernier caliper to measure the diameter of the inhibition zone by the cross method, measure three times and take the average value, and the result is expressed as the average value ± standard deviation.

[0061] Table 1 Inhibition zone diameters of different antibacterial peptides against Escherichia coli, Staphylococcus aureus and Candida albicans

[0062]

[0063]

[0064] From the results in Table 1, it can be seen that the inhibition zone diameter of antibacterial peptide a against Escherichia coli is 15.87 ± 0.21 mm (21.98% higher than Hylin PL), against Staphylococcus aureus is 17.89 ± 0.29 mm (11.60% higher than Hylin PL), and against Candida albicans is 5.11 ± 0.03 mm; compared with the antibacterial peptide Hylin PL, its antibacterial ability against Escherichia coli and Staphylococcus aureus has been improved to a certain extent, but the improvement is not particularly significant; while the inhibitory effect on Candida albicans is still weak, similar to the antibacterial peptide Hylin PL, indicating that the substitution of these two amino acids has no significant effect on the inhibitory effect on Candida albicans.

[0065] The inhibition zone diameter of antibacterial peptide b against Escherichia coli reaches 22.13 ± 0.24 mm (70.09% higher than Hylin PL), against Staphylococcus aureus is 29.22 ± 0.23 mm (82.28% higher than Hylin PL), and against Candida albicans is also 15.13 ± 0.20 mm (192.65% higher than Hylin PL). Compared with the original antibacterial peptide Hylin PL and antibacterial peptide a, the inhibition zone diameter has been greatly improved. It is suggested that the amino acid substitution at these positions and the C-terminal acetylation may significantly change the spatial structure and physicochemical properties of the antibacterial peptide, thereby enhancing its binding ability to the action targets such as bacterial or fungal cell membranes, and thus showing strong inhibitory ability against different types of strains (including Gram-positive bacteria, Gram-negative bacteria and the fungus Candida albicans), exerting an unexpected antibacterial effect. Therefore, it shows potential application value in the development of new antibacterial drugs.

[0066] The inhibition zone diameter of antimicrobial peptide c against Escherichia coli was 16.41 ± 0.26 mm (26.13% higher than Hylin PL), 19.30 ± 0.30 mm against Staphylococcus aureus (20.40% higher than Hylin PL), and 6.27 ± 0.19 mm against Candida albicans (21.28% higher than Hylin PL). Overall, its antibacterial effect was between that of antimicrobial peptide a and antimicrobial peptide b, indicating that the amino acid substitutions at these two positions and the C-terminal acetylation optimized its antibacterial performance to a certain extent, but the optimization degree was not as significant as that of antimicrobial peptide b.

[0067] Example 2

[0068] Preparation of hydrogel containing antimicrobial peptide b

[0069] (1) Dissolve polyvinyl alcohol (PVA) in 50% glycerol aqueous solution, heat to 60 °C, and stir for 2 h to ensure complete dissolution of PVA, obtaining a 10% (mass concentration) polyvinyl alcohol solution;

[0070] (2) Dissolve sodium carboxymethyl cellulose (Na-CMC) in 50% glycerol aqueous solution, and stir until completely dissolved to obtain a 1% (mass concentration) sodium carboxymethyl cellulose solution;

[0071] (3) Mix the polyvinyl alcohol solution and the sodium carboxymethyl cellulose solution according to a volume ratio of 1:1 to obtain a PVA / Na-CMC solution;

[0072] (4) Dissolve antimicrobial peptide b in deionized water to obtain a 0.5 mg / mL antimicrobial peptide b solution;

[0073] (5) Mix the antimicrobial peptide b solution and the PVA / Na-CMC solution according to a volume ratio of 1:10 to obtain a PVA / Na-CMC solution containing antimicrobial peptide b;

[0074] (6) Transfer the PVA / Na-CMC solution containing antimicrobial peptide b to the refrigerator, freeze at -20 °C for 8 hours, take out the obtained hydrogel, and thaw at room temperature for 1 hour;

[0075] (7) Place the hydrogel in the refrigerator again, freeze at -20 °C for 8 hours, and finally obtain the finished hydrogel containing antimicrobial peptide b.

[0076] Comparative Example 1

[0077] (1) Dissolve polyvinyl alcohol (PVA) in 50% glycerol aqueous solution, heat to 60 °C, and stir for 2 h to ensure complete dissolution of PVA, obtaining a 10% (mass concentration) polyvinyl alcohol solution;

[0078] (2) Dissolve sodium carboxymethyl cellulose (Na-CMC) in 50% aqueous glycerol solution, and stir until completely dissolved to obtain a 1% sodium carboxymethyl cellulose solution by mass concentration;

[0079] (3) Mix the polyvinyl alcohol solution and the sodium carboxymethyl cellulose solution in a volume ratio of 1:1 to obtain a PVA / Na-CMC solution;

[0080] (4) Transfer the PVA / Na-CMC solution to a refrigerator, freeze it at -20 °C for 8 hours, take out the obtained hydrogel, and thaw it at room temperature for 1 hour;

[0081] (5) Place the hydrogel in the refrigerator again, freeze it at -20 °C for 8 hours, and finally obtain the finished product of ordinary hydrogel.

[0082] Comparative Example 2

[0083] (1) Dissolve polyvinyl alcohol (PVA) in 50% aqueous glycerol solution, heat it to 60 °C, and stir for 2 h to ensure that the polyvinyl alcohol is completely dissolved, obtaining a 10% polyvinyl alcohol solution by mass concentration;

[0084] (2) Dissolve sodium carboxymethyl cellulose (Na-CMC) in 50% aqueous glycerol solution, and stir until completely dissolved to obtain a 1% sodium carboxymethyl cellulose solution by mass concentration;

[0085] (3) Mix the polyvinyl alcohol solution and the sodium carboxymethyl cellulose solution in a volume ratio of 1:1 to obtain a PVA / Na-CMC solution;

[0086] (4) Dissolve the antimicrobial peptide Hylin PL in deionized water to obtain a 0.5 mg / mL antimicrobial peptide Hylin PL solution;

[0087] (5) Mix the antimicrobial peptide Hylin PL solution and the PVA / Na-CMC solution in a volume ratio of 1:10 to obtain a PVA / Na-CMC solution containing the antimicrobial peptide Hylin PL;

[0088] (6) Transfer the PVA / Na-CMC solution containing the antimicrobial peptide Hylin PL to a refrigerator, freeze it at -20 °C for 8 hours, take out the obtained hydrogel, and thaw it at room temperature for 1 hour;

[0089] (7) Place the hydrogel in the refrigerator again, freeze it at -20 °C for 8 hours, and finally obtain the finished product of the hydrogel containing the antimicrobial peptide Hylin PL.

[0090] Example 3

[0091] Detect the antibacterial effect of the finished product of the hydrogel containing antimicrobial peptide b

[0092] (1) Cut the ordinary hydrogel finished product (hereinafter referred to as hydrogel a), the hydrogel finished product containing antibacterial peptide Hylin PL (hereinafter referred to as hydrogel b), and the hydrogel finished product containing antibacterial peptide b (hereinafter referred to as hydrogel c) into small round pieces with a diameter of 5 mm (thickness 0.5 mm);

[0093] (2) Irradiate hydrogel a, hydrogel b, and hydrogel c with an ultraviolet lamp for 20 minutes to ensure that the hydrogel surface is free of microbial contamination;

[0094] (3) Prepare bacterial suspensions of Escherichia coli, Staphylococcus aureus, and Candida albicans, and adjust the bacterial suspension concentration to 1×10 6 CFU / mL;

[0095] (4) In a sterile test tube, add 5 mL of sterile PBS, and add 100 μL of the bacterial suspension to the test tube and mix well;

[0096] (5) Add one piece of hydrogel a, hydrogel b, or hydrogel c to each test tube, and incubate at 37°C and 200 r / min for 6 h. At the same time, set up a blank control group without hydrogel, containing only PBS and the bacterial suspension;

[0097] (6) After incubation, pipette 100 μL of the mixed solution from each test tube, evenly spread it on a pre-prepared agar plate with a sterile spreader, and place it in a 37°C constant temperature incubator for 24 hours;

[0098] (7) After incubation, count the number of colonies on each plate, calculate the antibacterial rate ((number of colonies in the blank control group - number of colonies in the experimental group) / number of colonies in the blank control group), and the antibacterial rate results are as Figure 1 shown.

[0099] From Figure 1 the results, it can be seen that the hydrogel b containing the original antibacterial peptide has an antibacterial rate of 34.73% against Escherichia coli, 45.72% against Staphylococcus aureus, and a relatively low antibacterial rate against Candida albicans, close to 0. The hydrogel c containing the modified antibacterial peptide b of the present invention basically completely inhibits Escherichia coli and Staphylococcus aureus, and at the same time also has a new function of inhibiting Candida albicans. Its antibacterial rate after 6 hours of incubation reaches 75.19%, showing excellent effects.

[0100] Example 4

[0101] Detect the effect of the hydrogel finished product containing antibacterial peptide b on wound repair

[0102] (1) Select 18 10-week-old BALB / c mice. After one week of adaptive feeding, randomly divide them into three groups (6 mice in each group). Before the experiment, fast the mice for 12 hours to prevent the risk of food reflux;

[0103] (2) Anesthetize the experimental mice by intraperitoneal injection of 1% sodium pentobarbital. After confirming that the anesthesia has taken effect, carefully shave the hair on the back surgical area of the mice using an electric hair clipper, and then remove the remaining hair using an 8% sodium sulfide solution.

[0104] (3) Fix the hairless and clean mice on the operating board, disinfect twice with iodophor in sequence, and then deiodize with 75% alcohol.

[0105] (4) After disinfection, use a sterilized punch (diameter 1 cm) to punch holes in the back skin of the mice, excise the circular skin, and form a full-thickness skin defect wound surface.

[0106] (5) After washing the wound surface with sterile normal saline, cover the entire wound surface with equal amounts of hydrogel a, hydrogel b, and hydrogel c prepared by the present invention.

[0107] (6) Replace the hydrogel dressing once every 3 days. Take pictures on the 12th day and calculate the wound healing rate. The results are as Figure 2 shown.

[0108] From Figure 2 the data, it can be seen that after 12 days of treatment, there are differences in the wound healing conditions of the mice treated with different hydrogels. Specifically, for the mice treated with hydrogel a, the wound healing rate is 61.57%; for the mice treated with hydrogel b, the wound healing rate is 76.86%; while for the mice treated with hydrogel c, the wound healing rate is significantly higher, reaching 96.05%.

[0109] This result indicates that hydrogel c containing antimicrobial peptide b shows significant advantages in promoting wound healing, not only superior to hydrogel a without added antimicrobial peptide, but also significantly superior to hydrogel b added with antimicrobial peptide Hylin PL. Among them, antimicrobial peptide b in hydrogel c may significantly accelerate the wound healing process through characteristics such as stronger antibacterial effects, further demonstrating its potential and advantages in wound treatment.

Claims

1. A preparation method of a medical antibacterial repair hydrogel, characterized in that, The preparation method of the medical antibacterial repair hydrogel comprises the following steps: a) Dissolve polyvinyl alcohol in an aqueous glycerol solution to obtain a polyvinyl alcohol solution; b) Dissolve sodium carboxymethyl cellulose in an aqueous glycerol solution to obtain a sodium carboxymethyl cellulose solution; c) Mix the polyvinyl alcohol solution and the sodium carboxymethyl cellulose solution according to a volume ratio of 1:1 to obtain a PVA / Na-CMC solution; d) Dissolve the modified antibacterial peptide in deionized water to obtain a modified antibacterial peptide solution; e) Mix the modified antibacterial peptide solution and the PVA / Na-CMC solution according to a volume ratio of 1:10 to obtain a PVA / Na-CMC solution containing the modified antibacterial peptide; f) Transfer the PVA / Na-CMC solution containing the modified antibacterial peptide to a freezing device for primary freezing to obtain a hydrogel containing the modified antibacterial peptide; g) Take out the hydrogel, thaw it at room temperature, and then perform secondary freezing to obtain the medical antibacterial repair hydrogel; The amino acid sequence of the modified antibacterial peptide is FLWLIPALAGAIGKLIK-NH2.

2. The preparation method according to claim 1, wherein, The aqueous glycerol solution is a 50% aqueous glycerol solution; The polyvinyl alcohol solution is a 10% mass concentration polyvinyl alcohol solution; The concentration of the modified antibacterial peptide solution is greater than or equal to 0.5 mg / mL The sodium carboxymethyl cellulose solution is a 1% mass concentration sodium carboxymethyl cellulose solution; The conditions for primary freezing are freezing at -20°C for 8 hours, the room temperature thawing time is 1 hour, and the conditions for secondary freezing are freezing at -20°C for 8 hours.

3. The preparation method according to claim 2, wherein The medical antibacterial inhibits Gram-negative bacteria, Gram-positive bacteria, and fungi; The repair is for the healing repair of skin injury wounds, and the skin injury includes mechanical injury, physical injury, and chemical injury.

4. The preparation method according to claim 3, wherein The Gram-negative bacterium is Escherichia coli ATCC25922, the Gram-positive bacterium is Staphylococcus aureus ATCC 25923, and the fungus is Candida albicans ATCC10231.

5. The preparation method according to claim 4, characterized in that, The skin injury is a mechanical injury, and the mechanical injury is a cut injury.

6. A medical antibacterial repair hydrogel, characterized in that, The medical antibacterial repair hydrogel is prepared by the preparation method described in any one of claims 1-5.

7. Use of a modified antimicrobial peptide in the preparation of an antibacterial agent or an antibacterial hydrogel, characterized in that, The amino acid sequence of the modified antibacterial peptide is FLWLIPALAGAIGKLIK-NH2.

8. The application according to claim 7, wherein The antibacterial spectrum of the antibacterial agent is Gram-negative bacteria, Gram-positive bacteria, and fungi.

9. The application according to claim 8, wherein The Gram-negative bacterium is Escherichia coli ATCC25922, the Gram-positive bacterium is Staphylococcus aureus ATCC 25923, and the fungus is Candida albicans ATCC10231.

10. The application according to claim 9, wherein In the antibacterial agent or antibacterial hydrogel, the concentration of the modified antibacterial peptide is greater than or equal to 50 μg / mL.

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