CN113181422A

CN113181422A - Antibacterial nontoxic hydrogel dressing and preparation method thereof

Info

Publication number: CN113181422A
Application number: CN202110540273.5A
Authority: CN
Inventors: 郑汶江; 刘忠渊; 陈骞; 邹伟; 李颜利; 李嘉; 杨帆; 李慧; 刘波; 杨虎; 颜杰
Original assignee: Zhonghao Chenguang Research Institute of Chemical Industry Co Ltd; Sichuan University of Science and Engineering
Current assignee: Zhonghao Chenguang Research Institute of Chemical Industry Co Ltd; Sichuan University of Science and Engineering
Priority date: 2021-05-18
Filing date: 2021-05-18
Publication date: 2021-07-30

Abstract

The invention discloses an antibacterial nontoxic hydrogel dressing and a preparation method thereof. The hydrogel dressing comprises a hydrogel matrix and a bacteriostatic agent, and the hydrogel matrix and the bacteriostatic agent are physically crosslinked to prepare the bacteriostatic nontoxic hydrogel dressing; wherein the hydrogel matrix is polyvinyl alcohol or agarose, and the bacteriostatic agent is bacteriostatic peptide. The preparation method comprises the following steps: s1, weighing the hydrogel matrix, pouring the hydrogel matrix into a container, adding deionized water, stirring until the medicine is completely dissolved, and stopping heating to obtain a hydrogel matrix solution; s2, after the hydrogel matrix solution obtained in the S1 is cooled to room temperature, adding antibacterial peptide and stirring; freezing for 10-12 h after bubbles in the product disappear, and thawing to obtain antibacterial peptide hydrogel; and S3, coating an outer layer film on one side of the hydrogel, and then sticking and cutting release paper to obtain the antibacterial nontoxic hydrogel dressing. The hydrogel dressing prepared by the invention has a good antibacterial effect and is nontoxic, and the infection of wounds can be effectively avoided.

Description

Antibacterial nontoxic hydrogel dressing and preparation method thereof

Technical Field

The invention relates to the technical field of medical dressings, in particular to an antibacterial nontoxic hydrogel dressing and a preparation method thereof.

Background

Traditional surgery covers the wound with gauze, but the gauze needs to be replaced every few hours before the wound becomes scabbed. And the yarn is easy to adhere to the wound, so that the wound is easy to be secondarily damaged during replacement, a chronic wound is formed, healing is delayed, and even the life is possibly threatened. For this reason, hydrogel dressings have been developed in modern medicine. The inner layer of the hydrogel dressing is usually hydrogel which can be directly covered on a wound to promote wound healing, and the outer layer of the hydrogel dressing is non-woven fabric or polyurethane cloth which has good air permeability. Meanwhile, the hydrogel dosage form can improve the treatment efficiency of the medicine on the focus part and provide a better strategy for the clinical treatment of patients. However, the hydrogel material itself does not have bacteriostatic ability, so that when the hydrogel material is used as a medical dressing, the hydrogel material cannot inhibit bacteria at a wound and cannot promote rapid healing of the wound.

In contrast, some researchers add bacteriostatic components into hydrogel dressings in order to obtain hydrogel dressings with bacteriostatic effects. For example, bacteriostatic agents, dandelion extract and the like are added in the preparation process of the hydrogel dressing. However, most of the hydrogel dressings containing the bacteriostatic agent need to introduce a cross-linking agent and an initiator to complete the process from the monomer to the polymerization into the three-dimensional network structure in the preparation process of the existing hydrogel dressings containing the bacteriostatic agent. During the gel forming, the crosslinking agent and the initiator do not completely react and remain, and the residual crosslinking agent and the initiator exude after the gel forming. Most cross-linking agents and initiators are cytotoxic and irritating to the skin, not only do they tend to be detrimental to wound healing, but they also introduce new toxins.

Therefore, preparing a hydrogel dressing with good antibacterial performance and no toxicity is a technical problem to be solved by those skilled in the art.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to solve the problems of poor bacteriostatic effect and toxicity of the existing hydrogel material and provides a bacteriostatic non-toxic hydrogel dressing.

In order to solve the technical problems, the invention adopts the following technical scheme:

the bacteriostatic and nontoxic hydrogel dressing comprises a hydrogel matrix and a bacteriostatic agent, wherein the hydrogel matrix and the bacteriostatic agent are prepared by physical crosslinking to obtain the bacteriostatic and nontoxic hydrogel dressing; wherein the hydrogel matrix is polyvinyl alcohol or agarose, and the bacteriostatic agent is bacteriostatic peptide.

The antibacterial peptide consists of a plurality of connected cysteine residues, and is a cecropin XJ gene sequence amplified and separated from a plasmid pMD18-T-cecropin XJ carrying a cecropin XJ gene cDNA of silkworm. The cecropin XJ gene was cloned into a prokaryotic expression vector pET32a and expressed in E.coli and Staphylococcus aureus. The purified recombinant antibacterial peptide cecropin XJ has high stability to Escherichia coli and Staphylococcus aureus in the temperature range of 4-100 ℃.

The preparation method and gene sequence of the antibacterial peptide are disclosed in the paper: lijie Xia et al, Expression, Purification and characterization of a cephalosporin antigenic peptide from Bombyx mori in Saccharomyces cerevisiae, Protein Expression and Purification, 90(2013) 47-54.

The invention also provides a preparation method of the antibacterial nontoxic hydrogel dressing, which comprises the following steps:

s1, weighing the hydrogel matrix, pouring the hydrogel matrix into a container, adding deionized water, stirring at 80-100 ℃ until the medicine is completely dissolved, and stopping heating to obtain a hydrogel matrix solution;

s2, after the hydrogel matrix solution obtained in the S1 is cooled to room temperature, adding antibacterial peptide and stirring; freezing for 10-12 h after bubbles in the product disappear, and thawing to obtain antibacterial peptide hydrogel; wherein the mass ratio of the hydrogel matrix to the bacteriostatic agent to the deionized water is 10-15: 5-40: 100;

s3, coating an outer layer film on one side of the hydrogel, and then sticking release paper and cutting to obtain the bacteriostatic and nontoxic hydrogel dressing according to

claim

1 or 2.

Wherein, in step S2, the freezing and thawing steps are repeated three times. The freezing step is that the mixed solution of the hydrogel matrix and the antibacterial peptide is poured into a mould, a glass sheet is covered and fixed by a clamp, and then the glass sheet is put into a freezing chamber for freezing.

In step S3, the outer layer film may preferably be polyacrylate pressure sensitive adhesive.

In practical use, in step S2, the solution obtained by mixing the polyvinyl alcohol and the antimicrobial peptide may be spread on the surface of the grafted and modified expanded polytetrafluoroethylene film, and then the grafted and modified expanded polytetrafluoroethylene film may be frozen and thawed to obtain the antimicrobial peptide hydrogel. This can improve the strength of the hydrogel and improve the air-permeability and water-resistance properties of the hydrogel dressing.

Compared with the prior art, the invention has the following beneficial effects:

1. the invention adopts polyvinyl alcohol or agarose with larger molecular weight as hydrogel matrix, and can form hydrogel only by heating and stirring, so that a cross-linking agent and an initiator are not required to be introduced in the preparation process of the hydrogel, and the toxic substances in the prepared hydrogel are avoided.

2. The antibacterial peptide adopted by the invention consists of a plurality of connected cysteine residues, so that the antibacterial peptide has thermal stability and high solubility, can keep the original structure of the antibacterial peptide not to be damaged at 100 ℃, and still has antibacterial activity. The hydrogel matrix is dissolved and mixed with the antibacterial peptide at the high temperature of 100 ℃, and the high temperature can improve the solubility of the drug and promote the absorption of the drug. Therefore, the obtained hydrogel dressing has a good antibacterial effect and is nontoxic, and the infection of the wound can be effectively avoided. In addition, due to the existence of the hydrogel, the temperature of the wound can be effectively reduced, the wound can be kept moist, the pain feeling of the wound can be reduced, and the wound exudate can be effectively absorbed, so that the wound can be promoted to be rapidly healed. In the hydrogel dressing, the hydrophilic groups of the hydrogel wrap the amino groups of the antibacterial peptides, so that more antibacterial peptides can be fused into the hydrogel. Therefore, when the dressing is contacted with a wound, as the hydrogel dressing has high permeability, after the hydrogel absorbs wound exudate, the components of the wound exudate in the dressing can destroy the hydrogen bond structure of the antibacterial peptide and the hydrogel, so that the antibacterial peptide in the dressing is released, and the antibacterial effect is achieved.

3. The hydrogel dressing prepared by the invention has excellent air permeability and liquid absorption capacity, and the air permeability reaches 9000 g.m^-2·24h^-1The liquid absorption and seepage capacity is 22 g.100 cm^-2The permanent deformation of the dressing is less than 3%, and the extensibility is less than 0.2N cm^-1The swelling rate of the hydrogel layer is lower than 5% when the dressing is soaked in water, so that the dressing cannot deform when in use, and the comfort condition of the medical dressing is met.

4. The preparation method of the antibacterial nontoxic hydrogel dressing is simple in steps, convenient to operate, free of toxic and side effects and convenient to produce and implement. Polyvinyl alcohol can only be dissolved at high temperature, and most of antibacterial peptides can be decomposed at high temperature to lose the antibacterial activity.

Drawings

Fig. 1 is a schematic structural diagram of a hydrogel dressing prepared according to the invention, wherein 1 is an outer membrane, and 2 is hydrogel.

Fig. 2 is a physical diagram of the bacteriostatic non-toxic hydrogel dressing prepared in example 1.

Fig. 3 is a bacteriostatic circle diagram of the hydrogel dressing prepared in example 1, 1 is a bacteriostatic circle diagram of hydrogel without adding PBS buffer solution dropwise, and 2 is a bacteriostatic circle diagram of hydrogel with adding PBS buffer solution dropwise.

Fig. 4 is a bacteriostatic circle diagram of the bacteriostatic nontoxic hydrogel dressing prepared in examples 1, 3-5 against escherichia coli (E) and staphylococcus aureus (S). 1 is example 5, 2 is example 4, 3 is example 3, and 4 is example 1.

Fig. 5 is a graph of the bacteriostatic rate of the bacteriostatic non-toxic hydrogel dressings prepared in examples 1 and 3-5 on escherichia coli, wherein a is example 5, b is example 4, c is example 3, and d is example 1.

Fig. 6 is a graph showing the bacteriostatic rate of the bacteriostatic nontoxic hydrogel dressings prepared in examples 1 and 3-5 on staphylococcus aureus, wherein a is example 5, b is example 4, c is example 3, and d is example 1.

Fig. 7 shows the results of the wound healing experiments using the bacteriostatic non-toxic hydrogel dressings prepared in examples 1 and 3 and a blank control, wherein a is the blank control, B is the 20% bacteriostatic peptide hydrogel dressing prepared in example 3, and C is the 40% bacteriostatic peptide hydrogel dressing prepared in example 1; a is wound healing process, b is wound shrinkage rate, and c is a graph of body weight change of the experimental mice.

FIG. 8 is a view of a section of wound tissue; wherein, a is a tissue slice of a normal mouse, b is a tissue slice 14 days after blank control, c is a tissue slice 14 days after the bacteriostatic non-toxic hydrogel dressing prepared in the embodiment 1 is covered, and d is a tissue slice 14 days after the bacteriostatic non-toxic hydrogel dressing prepared in the embodiment 1 is covered on a wound.

Detailed Description

The present invention will be described in further detail with reference to the following examples and the accompanying drawings.

Component formula (mass ratio) of antibacterial nontoxic hydrogel dressing

TABLE 1

Preparation of bacteriostatic nontoxic hydrogel dressing

Example 1

A preparation method of antibacterial nontoxic hydrogel dressing comprises hydrogel matrix and antibacterial peptide. The hydrogel matrix is polyvinyl alcohol. The preparation method comprises the following steps:

s1, weighing 10 parts of polyvinyl alcohol (PVA), pouring into a round-bottom flask, adding 100 parts of deionized water, stirring at 100 ℃ until the medicine is completely dissolved, and stopping heating; and after the gel is cooled to room temperature, adding 40 parts of antibacterial peptide, pouring the prepared gel into a mold after bubbles in the product disappear, covering a glass sheet, fixing the glass sheet by a clamp, putting the glass sheet into a refrigerator for freezing for 12 hours, and unfreezing to obtain the polyvinyl alcohol/antibacterial peptide hydrogel.

S2, coating polyacrylate pressure-sensitive adhesive on one side of the hydrogel, and sticking the hydrogel onto a piece of release paper for cutting to obtain the bacteriostatic hydrogel dressing, as shown in figures 1 and 2.

Examples 2 to 5

The bacteriostatic non-toxic hydrogel dressings in examples 2 to 5 were prepared according to the same method as in example 1, except that the hydrogel matrix and the bacteriostatic peptide were added at different amounts and the stirring temperature in step S1 were different, as shown in table 1.

Example 6

Example 6 is different from example 1 in that in step S1 of example 6, a solution obtained by mixing polyvinyl alcohol and bacteriostatic peptide is spread on the surface of the expanded polytetrafluoroethylene film after graft modification, and then freezing and thawing are performed to obtain the bacteriostatic peptide hydrogel.

The preparation method of the expanded polytetrafluoroethylene film comprises the following steps:

(1) selecting a 150-micron-thick double-pulled expanded polytetrafluoroethylene film with the pore diameter of 0.1 micron, and cutting the film into a square shape of 10cm x 10 cm; fixing the expanded polytetrafluoroethylene film on plate glass, and putting the plate glass into a vacuum plasma generation bin with the frequency of 20 MHz; vacuumizing, introducing argon gas flow of 20mL/min, adjusting the power of equipment to be 115w, controlling the vacuum degree of a system to be 0.095MPa, and treating plasma for 100 s.

(2) Immediately transferring the membrane into a special mould, adding 1mol/L of vinyl pyrrolidone aqueous solution, introducing nitrogen to remove oxygen, and transferring to an ultraviolet lamp for irradiation grafting for 6 h.

(3) And (3) soaking the membrane into deionized water, changing water every 8 hours, and soaking for 24 hours to obtain the expanded polytetrafluoroethylene membrane.

Second, performance test of bacteriostatic nontoxic hydrogel dressing

First, the hydrogel dressings prepared in examples 1 to 6 were measured according to the test method for the national standard contact wound dressing (part 1: liquid absorbability) (YYT 0471.1-2004) (part 2: water vapor permeability of breathable film dressing) (YYT 0471.3-2004) (part 4: comfort) (YYT 0471.4-2004), and the test results are shown in table 2.

TABLE 2

As can be seen from Table 2, the hydrogel dressings prepared in examples 1 to 6 had air permeabilities of 5000 to 9000 g.m^-2·24h^-1And has excellent air permeability. The liquid absorptivity is 10-26 g.100 cm^-2Has certain capacity of absorbing seepage. The extensibility and the permanent deformability accord with the national standards of the dressing and meet the comfort requirement of the medical dressing.

And (II) applying the bacteriostatic non-toxic hydrogel dressing prepared in the example 1 to a bacteriostatic experiment. Two identical bacteriostatic non-toxic hydrogel dressings are taken, and one hydrogel dressing is about 0.6cm²About 10ul of PBS buffer (used to mimic the exudate at the wound) was dropped onto the hydrogel, and the other dressing was left untreated. Two dressings were placed in the same environment, and the zone of inhibition of two dressings was compared. Referring to fig. 3, 1 is a bacteriostatic circle of the hydrogel without adding PBS buffer solution dropwise, and 2 is a bacteriostatic circle of the hydrogel with PBS buffer solution dropwise. The hydrogel dressing prepared by the invention can react with the seepage at the wound during the use process. After the dressing absorbs the wound exudate, the wound is injuredThe components of the oral exudate can destroy the hydrogen bond structure of the antibacterial peptide and the hydrogel, so that the antibacterial peptide in the dressing is released, and the antibacterial effect is achieved and the antibacterial effect is better.

And (III) respectively measuring the performances of the hydrogel dressings prepared in the embodiments 1, 3, 4 and 5, such as the inhibition zone, the inhibition rate, the animal wound healing experiment and the like. The test was performed by sterilizing and dropping 10ul of PBS buffer solution on the surface of each dressing, and the test results are shown in Table 3. The inhibition zones and inhibition rates are shown in fig. 4-6. Wherein E is Escherichia coli, and S is Staphylococcus aureus.

TABLE 3

As can be seen from table 3, the hydrogel dressings prepared in examples 1, 3 and 4 have a bacteriostatic rate of > 99%, have excellent bacteriostatic properties, have a wound healing rate of > 95%, and have excellent ability to promote wound healing. In example 5, the added antibacterial peptide has a low content, and cannot prevent the growth of bacteria, so that the antibacterial peptide does not have antibacterial activity (the antibacterial rate is negative if bacteria exist).

From fig. 4, it can be seen that the higher the content of the antimicrobial peptide, the wider the inhibition zone, which indicates that the hydrogel dressing has better antimicrobial effect, and the hydrogel dressing has better antimicrobial effect on staphylococcus aureus than escherichia coli. Fig. 5 and 6 show that the hydrogel dressing has no bacteriostatic effect on escherichia coli and staphylococcus aureus when the content of the bacteriostatic peptide is 5%, and the hydrogel dressing has good bacteriostatic activity when the content of the bacteriostatic peptide exceeds 10%.

And (IV) applying the bacteriostatic non-toxic hydrogel dressing prepared in the example 1 to the results of the wound healing experiment.

The specific operation is as follows: a mouse model was used to test the healing effect of the hydrogel dressing on the wound. The weight of the mouse is 20 +/-2 g, and the mouse is adaptively raised for 1 week at the room temperature of 25 ℃ and the humidity of 40-50% before the experiment and is freely drunk by drinking water. The test environment is 21 ℃, the humidity is 51 percent, and the test environment is sterile. First, mice were anesthetized with a 2% chloral hydrate solution (15mL/kg body weight) by intraperitoneal injection before surgery, and then fixedFinally, the mark is made by picric acid. The skin of the back of the mice was then shaved and disinfected with 75% alcohol. The abdomen of the mouse is downward, the skin is cut along one side of the back ridge, the full layer of skin is cut by a scalpel, and the wound area is prepared by the scissors in an auxiliary way and is about 1cm². The 20% bacteriostatic peptide hydrogel dressing and the 40% bacteriostatic peptide hydrogel dressing samples are respectively lightly clamped by using sterilized forceps to cover the surface of the wound, then the wound is covered by using sterile gauze, and then the wound is bound by using an elastic bandage. The wound surface of the blank control group is only wrapped by sterile gauze and an elastic bandage. After the bandaging, the mice were kept in the cage and observed for their status. The wounds were carefully examined on

days

7 and 14, and wound sizes were tapped and measured to calculate the wound reduction rate as follows:

wherein A is₀Denotes the initial wound area, A_tThe area of the wound after 7 and 14 days is indicated.

The results of the experiment are shown in FIGS. 7 and 8. Fig. 7 shows the result of the wound healing experiment using the bacteriostatic nontoxic hydrogel dressing prepared in example 1, where a is the wound healing process, b is the wound shrinkage rate, and c is the weight change of the experimental mouse. Fig. 8 is a wound tissue section, a is a normal mouse tissue section, b is a tissue section 14 days after blank control, c is a tissue section 14 days after the bacteriostatic non-toxic hydrogel dressing prepared in example 12 is covered, and d is a tissue section 14 days after the bacteriostatic non-toxic hydrogel dressing prepared in example 1 is covered on the wound. As can be seen from fig. 7 (a), the healing rate of the wound covered with 40% of the bacteriostatic peptide hydrogel dressing was significantly faster than that of the wound covered with 20% of the bacteriostatic peptide hydrogel dressing and the blank control group. Immediately after the mouse is injured, the epidermal layer of the wound surface is necrotic and is dark red and purple, the wound is obviously swollen, and the boundary with the surrounding normal tissues is clear. After 7 days, the swelling of the wound covered by the 40% antibacterial peptide hydrogel dressing almost subsides, the wound is obviously healed, and the wound area is obviously reduced. After that, with the formation of granulation tissue, the wound surface epithelium is regenerated, the wound surface is basically healed, and scar tissue is formed. The wounds covered by the 20% bacteriostatic peptide hydrogel dressing are also reduced, but the swelling is obvious, and the wound edges have a scabbing phenomenon. After 14 days, the wound covered with the 40% bacteriostatic peptide hydrogel dressing is basically healed, the crust peels off, the scar tissue is reduced, the hair regeneration is carried out on the edge of the wound surface, and the function of the dermis is basically recovered. While the wound surface covered with 20% bacteriostatic peptide hydrogel dressing forms a scab. The reason for this difference in healing time is that the organism achieves the primary effect by eliminating pathogenic bacteria and restoring the inflammatory reaction of surrounding tissues when starting the wound healing mechanism, the duration and degree of the inflammatory reaction caused by bacteria play a critical role in restoring tissues, 40% of the bacteriostatic peptide hydrogel has long-lasting antibacterial property, and 20% of the bacteriostatic peptide hydrogel dressing has poor antibacterial property through bacteriostatic circle experiments.

In fig. 7, (b) and fig. 7(c) are the wound shrinkage and body weight change of the blank control, the 20% bacteriostatic peptide hydrogel dressing and the 40% bacteriostatic peptide hydrogel dressing respectively along with the change of time. As can be seen from the figure, the wound shrinkage of the wound covered with 40% bacteriostatic peptide hydrogel dressing is greater than that of the wound covered with 20% bacteriostatic peptide hydrogel dressing and the blank control. After 7 days, the shrinkage of the wound covered by the 40% chitosan hydrogel dressing reaches 81.5%, while the shrinkage of the wound covered by the 20% bacteriostatic peptide hydrogel dressing is 68.5%; after 14 days, the shrinkage of the wound covered with 40% bacteriostatic peptide hydrogel dressing reached 97.78%, while the shrinkage of the wound covered with 20% bacteriostatic peptide hydrogel dressing was 94%, which is close to the blank control. The 20% antibacterial peptide hydrogel dressing has a certain promotion effect on wound healing, on the basis, the 40% antibacterial peptide hydrogel dressing has the effects of sterilizing and diminishing inflammation of the wound, absorbing wound exudate and promoting cell regeneration, and the healing speed is faster and faster along with the increase of the healing time.

Fig. 8(a) is a tissue section of a normal mouse, (b) is a tissue section 14 days after blank control, (c) is a tissue section 14 days after a wound is treated by a 20% bacteriostatic peptide hydrogel dressing, and (d) is a tissue section 14 days after a wound is covered by a 40% bacteriostatic peptide hydrogel dressing. As can be seen from fig. 8(b) and 8(c), the epidermal cellular structure is substantially disappeared, the dermal layer is not recovered yet, and the dermal layer has a greater neutrophil infiltration. As can be seen from fig. 8(d), the epidermal layer has grown, the dermal layer has no obvious abnormality, and there is no obvious inflammatory cell infiltration, and it can be basically determined that the wound surface has healed. Through the analysis of the HE stained section 14 days after the wound, the wound covered by 40% of the bacteriostatic peptide hydrogel dressing is basically repaired 14 days after the wound is healed, the scab is basically and completely shed, and the new skin is shown; the slicing result shows that the skin of the rat is the same as that of a normal rat, no obvious abnormality is found in the epidermis layer, the dermis layer and the muscular layer, and the wound surface can be basically judged to be healed. The 20% antibacterial peptide hydrogel dressing only scabs and does not fall off, but subcutaneous blood vessel congestion can be found, and the slicing result also shows that the dermis has more neutrophil infiltration and still has inflammatory reaction, and tissues are still in the initial stage of a repair state.

Therefore, the hydrogel dressing prepared by the invention has a good antibacterial effect and is nontoxic, and the infection of the wound can be effectively avoided. In addition, due to the existence of the hydrogel, the temperature of the wound can be effectively reduced, the wound can be kept moist, the pain feeling of the wound can be reduced, the wound exudate can be effectively absorbed, and the wound can be rapidly healed.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the technical solutions, and those skilled in the art should understand that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all that should be covered by the claims of the present invention.

Claims

1. The bacteriostatic and nontoxic hydrogel dressing is characterized by comprising a hydrogel matrix and a bacteriostatic agent, wherein the hydrogel matrix and the bacteriostatic agent are prepared into the bacteriostatic and nontoxic hydrogel dressing through physical crosslinking; wherein the hydrogel matrix is polyvinyl alcohol or agarose, and the bacteriostatic agent is bacteriostatic peptide.

2. The non-toxic bacteriostatic hydrogel dressing according to claim 1, wherein the bacteriostatic peptide consists of a plurality of linked cysteine residues and is a cecropin XJ gene sequence amplified and isolated from plasmid pMD18-T-cecropin XJ carrying silkworm cecropin XJ gene cDNA.

3. A preparation method of a bacteriostatic nontoxic hydrogel dressing is characterized by comprising the following steps:

s3, coating an outer layer film on one side of the hydrogel, and then sticking release paper and cutting to obtain the bacteriostatic and nontoxic hydrogel dressing according to claim 1 or 2.

4. The method for preparing the bacteriostatic nontoxic hydrogel dressing according to claim 3, wherein the freezing and thawing steps are repeated three times in step S2.

5. The method for preparing a bacteriostatic and nontoxic hydrogel dressing according to claim 3, wherein in the step S2, the freezing step is to pour the mixed solution of the hydrogel matrix and the bacteriostatic peptide into a mold, cover the glass sheet, fix the glass sheet with a clamp, and freeze the glass sheet in a freezing chamber.

6. The method for preparing the bacteriostatic nontoxic hydrogel dressing according to the claim 3, wherein in the step S3, the outer layer film is preferably polyacrylate pressure sensitive adhesive.