Preparation method of gelatin composite sponge with antibacterial performance

Abstract

The invention belongs to the technical field of medical material preparation, and particularly relates to a preparation method of gelatin composite sponge with antibacterial performance. Comprising the following steps: (1) dissolving and stirring sodium alginate, adding gelatin, and continuously stirring; (2) adding a cross-linking agent into the gelatin / sodium alginate composite solution prepared in the step (1) in a high-speed stirring state, and reacting for a period of time to fully cross-link; and (3) pouring the product in the step (2) into a mold, pre-freezing at low temperature, and freeze-drying the cured product to obtain the gelatin composite dressing with the hemostatic function. (4) dissolving carboxymethyl chitosan in ultrapure water, and stirring with a magnetic stirrer until the carboxymethyl chitosan is completely dissolved to obtain a carboxymethyl chitosan solution; and (5) loading a carboxymethyl chitosan solution onto the hemostatic sponge prepared in the step (3) by adopting a dipping method, freezing and shaping, and then carrying out secondary freeze-drying to prepare the gelatin composite sponge with the antibacterial property. The toxic and side effects of the dressing are greatly reduced. And through the mutual synergistic effect of compounding of the gelatin and the sodium alginate, the mechanical property of the gelatin can be obviously improved, and the application range of the composite hemostatic dressing is expanded.

Description

Technical Field

[0001] The invention belongs to the technical field of medical material preparation, and in particular relates to a method for preparing a gelatin composite sponge with antibacterial properties. Background Art

[0002] In war, uncontrolled bleeding is the main cause of death among the wounded, accounting for more than 30% of the total number of deaths. In accidents or disasters, post-traumatic hemorrhage is the second leading cause of pre-hospital death. In military operations, the evacuation of the wounded may be greatly delayed due to many factors. Therefore, rapid and effective hemostasis of the wound is very important. Shortening the hemostasis time of the material and improving the hemostasis quality have become the best strategies to reduce the mortality rate of patients. However, the commonly used wound dressings, such as medical gauze, hemostatic cotton, hemostatic powder, etc., still have problems such as low hemostasis efficiency, easy to cause wound adhesion, and poor antibacterial effect. Therefore, in order to solve these problems, it is necessary to prepare a new multifunctional wound dressing.

[0003] Gelatin is a fibrous protein produced by partial heat denaturation of collagen. It is the main protein component of skin, bone and cartilage. Gelatin is usually extracted from collagen in connective tissues such as skin, bone and muscle of animals by hot water hydrolysis, and partially retains the collagen chain. Some active sequences of collagen are present in the gelatin backbone. In addition, gelatin contains different types of amino acids, and specific gelatin sequences may have a variety of different functions, including anti-oxidation, blood pressure reduction, antibacterial, promotion of tissue regeneration and wound healing. From the above description, it can be seen that gelatin has great application potential.

[0004] Although gelatin hemostatic products are generally safe and reliable products, the disadvantage of gelatin hemostatic products is that they have poor mechanical properties. When they come into contact with blood, they are easily damaged and have very weak pulling ability for blood cells and platelets. Therefore, it is difficult to stop bleeding from large wounds. It has poor adhesion, is easy to fall off, and is even more difficult to fix on visceral wounds. In addition, gelatin sponge promotes coagulation only when the coagulation factors in the body's blood are activated, so the hemostatic effect is not ideal for patients with coagulation disorders. Therefore, the best way to obtain high-performance gelatin hemostatic products is to compound them with other types of hemostatic materials. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a method for preparing a gelatin composite sponge with antibacterial properties. The dressing prepared by the method can quickly stop bleeding and reduce the amount of bleeding while also having good antibacterial properties. Moreover, the dressing has a three-dimensional network-like spatial structure, which can better promote wound healing.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] A method for preparing a gelatin composite hemostatic dressing with antibacterial properties comprises the following steps:

[0008] (1) dissolving sodium alginate in ultrapure water and heating and stirring on a magnetic stirrer for a period of time to completely dissolve the sodium alginate to obtain a sodium alginate solution; adding gelatin to the sodium alginate solution and continuing to heat and stir on a magnetic stirrer for a period of time to completely dissolve the gelatin to obtain a gelatin / sodium alginate composite solution;

[0009] (2) adding a crosslinking agent to the gelatin / sodium alginate composite solution prepared in step (1) under high-speed stirring, and reacting for a period of time to achieve full crosslinking;

[0010] (3) pouring the product of step (2) into a mold, pre-freezing at low temperature, and freeze-drying the solidified product to obtain a gelatin composite dressing with hemostatic function;

[0011] (4) dissolving carboxymethyl chitosan in ultrapure water, and stirring with a magnetic stirrer until the water is completely dissolved to obtain a carboxymethyl chitosan solution;

[0012] (5) The carboxymethyl chitosan solution is loaded onto the hemostatic sponge prepared in step (3) by an impregnation method, and after freezing and setting, a secondary freeze-drying is performed to obtain a gelatin composite sponge with antibacterial properties.

[0013] More preferably, in step (1), sodium alginate is dissolved in ultrapure water and heated and stirred at 40-60°C on a magnetic stirrer for 1-2 hours; gelatin is added to the sodium alginate solution, and heated and stirred at 40-60°C for 1-2 hours; the concentration of the gelatin solution in the gelatin / sodium alginate composite solution is 0.5%-1.5% (w / v), and the compounding ratio of gelatin to sodium alginate is 3:1-10:1. Furthermore, the compounding ratio of gelatin to sodium alginate is 8:1. The sponge morphology and electron microscopy results of other ratios are not ideal. An increase in the sodium alginate concentration will cause the sponge to become harder and the water absorption multiple to become lower.

[0014] More preferably, in step (2), the cross-linking agent is formaldehyde; formaldehyde (40%) is added to the gelatin / sodium alginate composite solution prepared in step (2) to a final concentration of formaldehyde (40%) of 0.5%-2%, and after cross-linking at room temperature for 30 minutes, the solution is poured into a plastic culture dish, pre-frozen at -80°C for 18-24 hours, and immediately placed in a freeze dryer for freeze drying for 48 hours after freezing. The pre-freezing stage is the initial stage of the freeze-drying process, which is a process of placing a liquid solution in a low temperature environment to freeze and freeze it into a solid state. Pre-freezing can prevent the boiling of the liquid caused by vacuuming during the freeze-drying process, maintain the structure and morphology of the sample before and after freeze-drying, and prevent irreversible changes such as bubbling, concentration, shrinkage, and solute migration during vacuum drying. Therefore, the pre-freezing stage plays an important role in the performance of the product.

[0015] The pre-freezing temperature must be at least lower than the eutectic point of the solution (lower than -10°C), otherwise the liquid cannot be completely crystallized after pre-freezing, and there will be partial boiling after turning on the vacuum pump, resulting in unstable material structure and rough and uneven surface. As the pre-freezing temperature decreases, the size of the pores decreases, which has a lot to do with the size of the ice crystals. That is, rapid freezing shortens the growth time of ice crystals, making it difficult for ice crystals to form large particles, thus forming a larger number of smaller ice crystals. The pores of the sponge are the space originally occupied by the ice crystals, which is consistent with the size of the ice crystals. Therefore, the size of the ice particles formed during freezing determines the pore size of the sponge. When the temperature is higher than -80°C (-40°C), crystals form on the contact surface between the sponge and the container, and stratification occurs, affecting the mechanical properties and appearance of the sponge.

[0016] More preferably, the concentration of the carboxymethyl chitosan solution in step (4) is 0.1%-0.4%. If the formaldehyde concentration is too low, the cross-linking effect will be affected and the sponge will dissolve in water. If the formaldehyde concentration is too high, the toxic side effects will increase and the sponge will become hard.

[0017] More preferably, the immersion in step (5) is to immerse the hemostatic sponge in the carboxymethyl chitosan solution for 2-5 hours.

[0018] More preferably, the present invention also provides a gelatin composite sponge with antibacterial properties prepared according to the above method, which has a thickness of 0.5 cm and an overall loose three-dimensional network pore structure. The porosity can reach about 95%, the tensile strength is 0.11-0.15Mpa, the elongation at break is 7%, the water absorption multiple is 40-60 times, the moisture retention rate is 32%-38%, and the antibacterial rate against Staphylococcus aureus can reach more than 99.9%.

[0019] Beneficial effects:

[0020] 1. Sodium alginate is a natural anionic polysaccharide. It contains a large number of hydrophilic groups such as carboxyl and hydroxyl groups in its molecules. It has good biocompatibility and certain biodegradability, and has the ability to form films and gels. The dressing prepared by compounding gelatin and sodium alginate has significantly improved hemostatic performance compared to simple gelatin dressings, but has poor antibacterial performance. The present invention improves the antibacterial properties of the sponge by adding carboxymethyl chitosan to the dressing. Compared with antibacterial dressings on the market, carboxymethyl chitosan, as a natural substance, greatly reduces the toxic and side effects of the dressing. Through the synergistic effect of compounding gelatin and sodium alginate, the mechanical properties of gelatin can be significantly improved, expanding the scope of application of the composite hemostatic dressing.

[0021] 2. Cross-linking with formaldehyde is a chemical cross-linking method to improve the tension and stability of the composite dressing, forming a denser three-dimensional network structure that is not easily damaged and can be used to stop bleeding in larger wounds. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 Schematic diagram of the microstructure of pure gelatin sponge;

[0024] Figure 2 A schematic diagram of the microstructure of the invented gelatin / sodium alginate composite dressing;

[0025] Figure 3 Schematic diagram of the microstructure of Example 2 of the present invention;

[0026] Figure 4 This is a graph showing the antibacterial performance test results of different types of gelatin hemostatic dressings. DETAILED DESCRIPTION

[0027] Hereinafter, the present invention will be described in detail. Before describing, it should be understood that the terms used in this specification and the appended claims should not be interpreted as being limited to the general meaning and dictionary meaning, but should be interpreted according to the meaning and concept corresponding to the technical aspects of the present invention on the basis of the principle that the inventor is allowed to appropriately define the terms for the best interpretation. Therefore, the descriptions presented here are only preferred examples for illustrative purposes and are not intended to limit the scope of the present invention, so that it should be understood that other equivalents or improvements can be obtained therefrom without departing from the spirit and scope of the present invention.

[0028] The following examples are only listed as examples of embodiments of the present invention and do not constitute any limitation to the present invention. It can be understood by those skilled in the art that modifications within the scope of the essence and concept of the present invention fall within the scope of protection of the present invention. Unless otherwise specified, the reagents and instruments used in the following examples are all commercially available products.

[0029] Hereinafter, the preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Before the description, it should be understood that the terms used in the specification and the appended claims should not be interpreted as limited to the general and dictionary meanings, but should be interpreted based on the principle of allowing the inventor to appropriately define the terms for the best interpretation, based on the meaning and concept corresponding to the technical level of the present invention. Therefore, the description herein is only a preferred example for illustrative purposes, and is not intended to limit the scope of the present invention, so it should be understood that other equivalent implementations and modifications can be made without departing from the spirit and scope of the present invention.

[0030] As used herein, the terms "include", "comprising", "having", "containing" or any other similar terms are open-ended transitional phrases, which are intended to cover non-exclusive inclusions. For example, a composition or article containing multiple elements is not limited to the elements listed herein, but may also include other elements that are not explicitly listed but are generally inherent to the composition or article. In addition, unless otherwise expressly stated, the term "or" refers to an inclusive "or" rather than an exclusive "or". For example, any of the following situations satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), and both A and B are true (or exist). In addition, as used herein, the terms "include", "comprising", "having", and "containing" should be interpreted as having been specifically disclosed and simultaneously covering closed or semi-closed transitional phrases such as "consisting of" and "consisting essentially of".

[0031] In this article, all features or conditions defined in the form of numerical ranges or percentage ranges are only for brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be deemed to have covered and specifically disclosed all possible secondary ranges and individual values ​​within the range, especially integer values. For example, the range description of "1 to 8" should be deemed to have specifically disclosed all secondary ranges such as 1 to 7, 2 to 8, 2 to 6, 3 to 6, 4 to 8, 3 to 8, etc., especially secondary ranges defined by all integer values, and should be deemed to have specifically disclosed individual values ​​such as 1, 2, 3, 4, 5, 6, 7, 8, etc. within the range. Unless otherwise specified, the above interpretation method applies to all contents of the entire present invention, regardless of whether the range is broad or not.

[0032] If the quantity or other numerical value or parameter is expressed as a range, a preferred range or a series of upper and lower limits, it should be understood that all ranges consisting of any upper limit or preferred value of the range and the lower limit or preferred value of the range have been specifically disclosed herein, regardless of whether these ranges are disclosed separately. In addition, if a numerical range is mentioned herein, unless otherwise specified, the range should include its endpoints and all integers and fractions within the range.

[0033] In this document, under the premise of achieving the purpose of the invention, numerical values ​​should be understood to have the accuracy of the number of significant digits of the numerical value. For example, the number 40.0 should be understood to cover the range from 39.50 to 40.49.

[0034] In addition, unless otherwise stated, the following reagents, solvents and equipment were purchased from:

[0035] Sodium alginate medical grade Shaanxi Changji Fu Biotechnology Co., Ltd.

[0036] Gelatin Medical Grade Rousselot Gelatin Co., Ltd.

[0037] Formaldehyde analytical grade (AR) Yantai Yuandong Fine Chemical Co., Ltd.

[0038] Carboxymethyl Chitosan Medical Grade Xi'an Tianhe Pharmaceutical Co., Ltd.

[0039] Heating and stirring were carried out by using HJ-4B dual digital display constant temperature magnetic stirrer from Xinrui Instrument Co.

[0040] The electron microscope image was observed by SEM3200A scanning electron microscope of Guoyi Quantum Technology Co., Ltd.

[0041] The sponge was prepared by a KST-18 vacuum freeze dryer from Shandong Custer Instrument Co., Ltd.

[0042] The tensile strength was measured by a CMT6503 universal testing machine from Meters Industries.

[0043] Example 1

[0044] A method for preparing a gelatin composite sponge with antibacterial properties comprises the following steps:

[0045] (1) dissolving sodium alginate in ultrapure water, and heating and stirring at 60° C. for 2 h on a magnetic stirrer to completely dissolve the sodium alginate to obtain a sodium alginate solution; adding gelatin to the sodium alginate solution, and continuing to heat and stir at 40° C. for 2 h on a magnetic stirrer to completely dissolve the gelatin to obtain a gelatin / sodium alginate composite solution; the concentration of the gelatin solution in the gelatin / sodium alginate solution is 0.8%-1.2%, and the composite ratio of gelatin to sodium alginate is 4:1;

[0046] (2) adding 1.5% formaldehyde (40%) solution to the gelatin / sodium alginate composite solution prepared in step (1) under a magnetic stirrer at a stirring speed of 950-1200 rpm, and continuing the reaction for 1 hour to achieve full cross-linking;

[0047] (3) pouring the product of step (2) into a mold, pre-freezing at -80°C for 24 hours, and placing the solidified product in a freeze dryer for freeze drying for 48 hours to obtain a gelatin composite dressing with hemostatic function;

[0048] (4) dissolving carboxymethyl chitosan in ultrapure water, stirring with a magnetic stirrer for 1 h at a stirring speed of 950-1200 rpm until the carboxymethyl chitosan is completely dissolved, to obtain a carboxymethyl chitosan solution with a concentration of 0.2%;

[0049] (5) The carboxymethyl chitosan solution is loaded onto the hemostatic sponge prepared in step (3) by an immersion method, pre-frozen at -80°C for 12 hours, frozen and shaped, and then freeze-dried for a second time for 24 hours to obtain a gelatin composite sponge with antibacterial properties; the immersion time of the hemostatic sponge is 5 hours.

[0050] Example 2

[0051] A method for preparing a gelatin composite sponge with antibacterial properties comprises the following steps:

[0052] (1) dissolving sodium alginate in ultrapure water, and heating and stirring at 60° C. for 1 hour on a magnetic stirrer to completely dissolve the sodium alginate to obtain a sodium alginate solution; adding gelatin to the sodium alginate solution, and continuing to heat and stir at 40° C. for 1 hour on a magnetic stirrer to completely dissolve the gelatin to obtain a gelatin / sodium alginate composite solution; the concentration of the gelatin solution in the gelatin / sodium alginate solution is 0.8%-1.2%, and the composite ratio of gelatin to sodium alginate is 8:1;

[0053] (2) adding 1.5% formaldehyde (40%) solution to the gelatin / sodium alginate composite solution prepared in step (1) under high-speed stirring, and continuing the reaction for 30 minutes to achieve full cross-linking;

[0054] (3) pouring the product of step (2) into a mold, pre-freezing at -80°C for 18 hours, and placing the solidified product in a freeze dryer for freeze drying for 48 hours to obtain a gelatin composite dressing with hemostatic function;

[0055] (4) dissolving carboxymethyl chitosan in ultrapure water and stirring with a magnetic stirrer for 1 h until completely dissolved to obtain a carboxymethyl chitosan solution with a concentration of 0.2%;

[0056] (5) The carboxymethyl chitosan solution is loaded onto the hemostatic sponge prepared in step (3) by an immersion method, pre-frozen at -80°C for 12 hours, frozen and shaped, and then freeze-dried for a second time for 24 hours to obtain a gelatin composite sponge with antibacterial properties; the immersion time of the above hemostatic sponge is 3 hours.

[0057] Example 3

[0058] 1. Microscopic morphology test of gelatin composite sponge with antibacterial properties:

[0059] Using the method of Example 2, gelatin and sodium alginate were compounded at a content ratio of 8:1, and 0.2% carboxymethyl chitosan was added to one group, and not added to the other group. The composite dressing products with better appearance were selected for scanning electron microscopy detection and compared with the uncompounded gelatin to observe the fiber thickness, pore size, pore size distribution, etc. Figure 1-3 It can be seen from the scanning electron microscope image shown that: compared with pure gelatin, the pores of the dressing are more transparent after compounding with sodium alginate; after adding carboxymethyl chitosan, the pore distribution of the dressing is more uniform, the structure is denser, and the pores are significantly increased.

[0060] 2. Determination of physical properties of different types of gelatin hemostatic dressings:

[0061] The physical properties of three gelatin hemostatic dressings were tested by tensile strength, elongation at break, water absorption multiple, and moisture retention rate. The physical properties of the composite sponge prepared in Example 2 were studied. And the performance was compared with pure gelatin sponge and gelatin / sodium alginate composite sponge. As shown in Table 1, the physical properties of different types of gelatin hemostatic dressings are very different, among which the performance test results of the gelatin composite sponge prepared in Example 2 are the best. Compared with the simple gelatin dressing, the tensile strength and water absorption multiple of the gelatin / sodium alginate composite dressing are significantly improved, indicating that the gelatin and sodium alginate composite dressings have a synergistic effect, which can significantly improve the mechanical properties of gelatin and expand the application range of the composite hemostatic dressing. Compared with the gelatin / sodium alginate dressing, the tensile strength and water absorption multiple of the dressing prepared in Example 2 are also significantly improved, and the free amino groups contained in the carboxymethyl chitosan can be cross-linked with gelatin to produce a synergistic effect. From the performance test results of the three dressings, it can be seen that with the increase of water absorption ratio, the moisturizing rate shows a downward trend. This may be because the greater the water absorption ratio of the sponge, the larger its pores. The increase in the pores of the sponge leads to a decrease in the water retention capacity of the sponge.

[0062] The calculation method is as follows:

[0063] Tensile Strength:

[0064] The sponge was cut into strip specimens with a length, width and height of 30×20×10 mm using a scalpel. The tensile strength test of the sponge cube was performed using a small universal testing machine at a speed of 10 mm / min. The test was repeated five times and the average value was taken.

[0065] Elongation at break:

[0066] Set the tensile tester's tensile speed to 20mm / min, the holding distance to 20mm, and record the maximum force during the sample stretching process as the breaking strength in Newtons (N). If multiple strength peaks appear during the test, take the highest value as the breaking strength. Record the elongation of the sample at the breaking strength as the breaking elongation. Calculation method of breaking elongation;

[0067] Eb=(L-L0) / L0×100%

[0068] Eb: elongation at break, expressed in %;

[0069] L: specimen fracture gauge length, in millimeters (mm)

[0070] L0: original gauge length of the sample, in millimeters (mm)

[0071] Calculation method of water absorption multiple: Take a sample of a certain area (1cm×1cm), weigh it accurately, record it as m1, immerse it in a beaker of water, rub it gently with your fingers until it is completely soaked and all the air is removed. After absorbing enough water, use tweezers to gently pinch one corner to take it out of the water, hold the tweezers gently on the water surface to drain for 1 minute, weigh it again, record it as m2, and calculate the water absorption multiple according to the formula.

[0072] A=(m2-m1) / m1

[0073] Where:

[0074] A--water absorption multiple of the sample;

[0075] m1--The mass of the sample before wetting, in grams (g);

[0076] m2--The mass of the sample after being soaked, in grams (g).

[0077] Water retention test: Cut the freeze-dried sponge into 2.5cm×2.5cm×1cm cubes, take 5 cubes, weigh them accurately (WA), and place them in a small beaker with 20mL of distilled water. After the sponge fully absorbs water, take it out and use filter paper to absorb the surface water until the weight no longer changes, and weigh it (WB). Put the sponge after water absorption into a desiccator, use silica gel as a desiccant, and place it at room temperature for 1 day, and weigh it (WC). The water retention rate (W) is calculated as follows:

[0078] W=(WC-WA) / (WB-WA)×100%.

[0079] Table 1 shows the results of physical properties test of different types of gelatin hemostatic dressings

[0080]

[0081]

[0082] 3. Determination of antibacterial properties of different types of gelatin dressings

[0083] The antibacterial properties of pure gelatin dressings, gelatin / sodium alginate composite dressings and dressings prepared according to Example 2 were tested respectively to study the antibacterial properties of different types of gelatin dressings. The specific experimental operation of the antibacterial test was as follows: the gelatin dressing was cut into discs with a diameter of 10 mm and a thickness of 1 mm, and sterilized under ultraviolet light for 5 min. Agar solid culture medium was prepared, sterilized by high pressure, and plated. After the culture medium was cooled and solidified, 100 μL of a 5×10 6 CFU / mL bacterial (Staphylococcus aureus) suspension was evenly spread on the surface of the solid culture medium, and then the disc sample was gently adhered to the surface of the culture medium and cultured at 37°C for 24 hours. Observe and take pictures, and measure the size of the inhibition zone. The results are as follows Figure 4 As shown in the figure, it can be seen that the gelatin dressing has no antibacterial property, and the gelatin / sodium alginate composite dressing has antibacterial property, but the antibacterial property is poor; Example 2 is based on the gelatin / sodium alginate composite dressing and carboxymethyl chitosan is added. The test results show that its antibacterial property can reach 99.9%, indicating that the sponge rich in carboxymethyl chitosan has a strong antibacterial ability against Staphylococcus aureus.

[0084] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for preparing a gelatin composite hemostatic dressing with antibacterial properties, characterized in that: The following steps are involved: (1) dissolving sodium alginate in ultrapure water and heating and stirring on a magnetic stirrer for a period of time to completely dissolve the sodium alginate to obtain a sodium alginate solution; Add gelatin to the sodium alginate solution and continue to heat and stir on a magnetic stirrer for a period of time to completely dissolve the gelatin to obtain a gelatin / sodium alginate composite solution; (2) adding a crosslinking agent to the gelatin / sodium alginate composite solution prepared in step (1) under high-speed stirring, and reacting for a period of time to achieve full crosslinking; (3) pouring the product of step (2) into a mold, pre-freezing at low temperature, and freeze-drying the solidified product to obtain a gelatin composite dressing with hemostatic function; (4) dissolving carboxymethyl chitosan in ultrapure water, and stirring with a magnetic stirrer until the water is completely dissolved to obtain a carboxymethyl chitosan solution; (5) The carboxymethyl chitosan solution is loaded onto the hemostatic sponge prepared in step (3) by an impregnation method, and after freezing and setting, a secondary freeze-drying is performed to obtain a gelatin composite sponge with antibacterial properties.

2. The method for preparing a gelatin composite hemostatic dressing with antibacterial properties according to claim 1, characterized in that: In step (1), sodium alginate is dissolved in ultrapure water and heated and stirred at 40-60° C. for 1-2 hours on a magnetic stirrer; gelatin is added to the sodium alginate solution, and heated and stirred at 40-60° C. for 1-2 hours; the concentration of the gelatin solution in the gelatin / sodium alginate composite solution is 0.5%-1.5% (w / v), and the composite ratio of gelatin to sodium alginate is 3:1-10:

1.

3. The method for preparing a gelatin composite hemostatic dressing with antibacterial properties according to claim 1, characterized in that: In step (1), the compounding ratio of gelatin to sodium alginate is 8:

1.

4. The method for preparing a gelatin composite hemostatic dressing with antibacterial properties according to claim 1, characterized in that: In step (2), the cross-linking agent is formaldehyde; formaldehyde (40%) is added to the gelatin / sodium alginate composite solution prepared in step (2) to make the final concentration of formaldehyde (40%) be 0.5%-2%, after cross-linking at room temperature for 30 minutes, pour into a plastic culture dish, pre-freeze at -80°C for 18-24 hours, and immediately put into a freeze dryer for freeze drying for 48 hours after freeze setting.

5. The method for preparing a gelatin composite hemostatic dressing with antibacterial properties according to claim 1, characterized in that: The concentration of the carboxymethyl chitosan solution in step (4) is 0.1%-0.4%.

6. The method for preparing a gelatin composite hemostatic dressing with antibacterial properties according to claim 1, characterized in that: The immersion described in step (5) is to immerse the hemostatic sponge in the carboxymethyl chitosan solution for 2-5 hours.

7. A gelatin composite sponge with antibacterial properties prepared according to the method of claims 1-5, having a thickness of 0.5 cm, a loose three-dimensional network pore structure as a whole, a porosity of 95%, a tensile strength of 0.11-0.15 MPa, an elongation at break of 7%, a water absorption multiple of 40-60 times, a moisture retention rate of 32%-38%, and an antibacterial rate against Staphylococcus aureus of more than 99.9%.

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