A method for preparing antibacterial material and its application

Abstract

The present invention relates to the field of high molecular polymers, to an antibacterial product, and specifically to a method for preparing an antibacterial material and its application. A double-layer antibacterial material with multiple responses to stimulation is obtained by separately synthesizing a nanoemulsion having guanidine hydrochloride and a gelatin solid, and assembling the gelatin. This double-layer antibacterial material has a pH gating mechanism, which can improve the pH sensitivity of the antibacterial material, slowly release the active material under pH conditions, and improve the antibacterial effect through the synthesized new guanidine hydrochloride. Compared with the prior art, the present invention has the effects of enhancing interface bonding, reducing dissolution, promoting healing, and gated release, which solves the dissolution toxicity and physical property limitations of the antibacterial materials in the prior art.

Description

Technical Field

[0001] The present invention relates to the field of high molecular polymers, to an antibacterial product, and more specifically to a method for preparing an antibacterial material and its application. Background Art

[0002] Currently, widely used disinfectants lack safety and mildness, often exhibiting toxicity, odor, corrosiveness, or skin irritation, making them unsuitable for sterilization applications involving direct human contact. For example, hypochlorous acid, used to disinfect skin and surfaces, has an unpleasant odor, decomposes easily, and is difficult to store. Alcohol (ethanol), commonly used for skin disinfection, is flammable, explosive, and highly irritating, making it highly dangerous to store and transport. These traditional disinfectants all have significant drawbacks and cannot meet practical needs. Summary of the Invention

[0003] In order to solve the above problems, the present invention provides a method for preparing an antibacterial material and its application. A chitosan-polyguanidine polymer with pH response is prepared by introducing an imine bond, and a double-layer antibacterial material with multiple response stimuli is obtained by assembling gelatin, which can directly act on the human wound to disinfect and sterilize.

[0004] In order to achieve the above-mentioned purpose, the technical solutions adopted by the present invention are as follows:

[0005] In a first aspect, the present invention provides a method for preparing an antibacterial material, comprising the following steps: dissolving 2 wt% chitosan in a 1 wt% acid solution at a weight percentage ratio of 2:1, stirring the solution for 2 hours at 25°C to form a solution, adding an active component to the solution to form an intermediate solution, and centrifuging the intermediate solution to remove bubbles in the solution; the active component is the guanidine hydrochloride, which is poly-2-methyl-pentamethyleneguanidine hydrochloride, having the following structural formula: , wherein the degree of polymerization n=60~100; the intermediate solution and the nanoemulsion are mixed and stirred in a weight ratio of (2~1):(1~2) to form a mixed solution, and the mixed solution is mixed on a gelatin solid and dried to obtain the antibacterial material; the antibacterial material has a double-layer structure, the first layer is a gelatin solid formed by drying the gelatin solution, and the second layer is an active substance formed by drying the active component and the nanoemulsion loaded with chitosan as a carrier, and the active substance is encapsulated in the gelatin solid.

[0006] In some specific implementations, obtaining the gelatin solution includes the following steps: adding 2 wt% gelatin and 1 wt% glycerol to distilled water, and heating and stirring at 60°C to obtain an initial gelatin solution, adding 0.5 wt% to 5 wt% tannic acid to the initial gelatin solution and accelerating stirring and dissolving at 40°C to obtain the gelatin solution; the gelatin solid is obtained by drying the gelatin solution at 35°C for 4 hours.

[0007] In some specific implementations, the nanoemulsion is obtained by mixing and stirring an oil phase with a concentration of 10% and an aqueous phase with a concentration of 90%, and the oil phase is obtained by ultrasonically adding an emulsifier with a mass ratio of 5% to 10% of the oil phase and an essential oil with a mass ratio of 90% to 95% of the oil phase; the ultrasonic power ratio is 50% to 90%, and the ultrasonic time is 5 min to 25 min.

[0008] In some specific implementations, the poly-2-methyl-pentamethyleneguanidine hydrochloride is obtained by synthesizing 2-methyl-1,5-pentanediamine and guanidine hydrochloride.

[0009] In some specific implementations, the preparation method of the poly-2-methyl-pentamethyleneguanidine hydrochloride specifically includes: subjecting 2-methyl-1,5-pentanediamine and guanidine hydrochloride in a molar ratio of 1:1 to a multi-stage temperature increase reaction under a nitrogen atmosphere to obtain a polymer melt; the multi-stage temperature increase reaction includes a first temperature increase reaction stage, a second temperature increase reaction stage, and a third temperature increase reaction stage, the target temperature range of the first temperature increase reaction stage is 75°C~85°C, the target temperature range of the second temperature increase reaction stage is 115°C~125°C, and the target temperature range of the third temperature increase reaction stage is 175°C~185°C.

[0010] In some specific implementations, the method for preparing poly-2-methyl-pentamethyleneguanidine hydrochloride further includes: pressing the polymer melt into purified water based on nitrogen pressure and stirring, dissolving, and filtering to collect an aqueous solution containing crude 2-methyl-pentamethyleneguanidine hydrochloride; purifying, concentrating, and drying the aqueous solution containing crude 2-methyl-pentamethyleneguanidine hydrochloride by ion exchange to obtain the poly-2-methyl-pentamethyleneguanidine hydrochloride.

[0011] In some specific implementations, after the first temperature rising reaction stage is completed, stirring is performed for 15 to 30 minutes to obtain the first stage product; after the second temperature rising reaction stage is completed based on the completion of the first stage product heating, the ammonia in the reaction process is removed and collected to obtain the intermediate product; after the third temperature rising reaction stage is completed based on the completion of the intermediate product heating, the reactants are stirred for 2 to 3 hours to obtain the polymer melt.

[0012] In some specific implementations, the purity of the poly-2-methyl-pentamethyleneguanidine hydrochloride is greater than or equal to 99%.

[0013] In some specific implementations, the acid solution includes glacial acetic acid. The acid solution includes glacial acetic acid.

[0014] In a second aspect, there is provided an application of an antibacterial material prepared by any of the methods described above in a medical dressing.

[0015] The technical solution provided in the embodiment of the present application provides a new antibacterial material matrix for disinfecting wounds and wounds on the human body. A double-layer antibacterial material with multiple responses to stimulation is obtained by synthesizing a nanoemulsion containing guanidine hydrochloride and a gelatin solid separately, and assembling the gelatin. This double-layer antibacterial material has a pH gating mechanism, which can improve the pH sensitivity of the antibacterial material, slowly release the active material under pH conditions, and improve the antibacterial effect through the synthesized new guanidine hydrochloride. Compared with the existing technology, the present invention has the effects of enhancing interfacial bonding, reducing dissolution, promoting healing and gated release, which solves the dissolution toxicity and physical property limitations of the antibacterial materials in the existing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 This is a flow chart of the method for preparing antibacterial materials provided by the present application.

[0018] Figure 2 The present invention provides a flow chart of the synthesis method of guanidine hydrochloride.

[0019] Figure 3 It is a schematic diagram of the pH response and controlled release performance experimental results provided by the present application.

[0020] Figure 4 It is a schematic diagram of the experimental results of the inhibition zone method provided by the present application.

[0021] Figure 5 It is a schematic diagram of the experimental results of the inhibition zone method provided by the prior art. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. If specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially. The embodiments described below are part of the embodiments of the present invention, rather than all of the embodiments. In conjunction with the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention.

[0023] In one embodiment of the present invention, a method for preparing an antimicrobial material is provided, for preparing a dual-responsive antimicrobial material. Furthermore, in another embodiment of the present invention, a method for using the antimicrobial material in a medical dressing is provided.

[0024] Among them, the antibacterial material provided in this embodiment has a double-layer structure. The first layer is a gelatin solid formed after the gelatin solution is dried, and the second layer is an active substance formed after the nanoemulsion is dried and is wrapped in the gelatin solid and loaded with active components using chitosan as a carrier.

[0025] Specifically, the active component in this embodiment is guanidine hydrochloride. Among them, guanidine hydrochloride is used as the antibacterial main body, chitosan is used as a carrier and is combined with the nanoemulsion through the amino group on the chitosan to form an imine bond, thereby obtaining a carrier material that is sensitive to pH. By combining this carrier material with guanidine hydrochloride, it has good antibacterial activity and controlled release performance. Among them, the nanoemulsion is obtained by mixing and stirring an oil phase with a concentration of 10% and an aqueous phase with a concentration of 90%, wherein the oil phase is obtained by ultrasonically mixing an emulsifier with a mass ratio of 5% to 10% of the oil phase and an essential oil with a mass ratio of 90% to 95% of the oil phase. Moreover, in order to further enhance the biological activity of the material, in this embodiment, plant essential oils are preferred for the essential oils, and tsaoko essential oil is the best choice. Among them, a mixed emulsifier is selected for the emulsifier, which is obtained by mixing two emulsifiers, Tween 20 and sucrose fatty acid ester, in equal proportions.

[0026] In one embodiment, in order to enable this antibacterial material to act directly on the human body and provide a highly effective antibacterial effect, guanidine hydrochloride is obtained through a new synthesis method. Specifically, the guanidine hydrochloride in this embodiment is a poly-2-methyl-pentamethyleneguanidine hydrochloride, which has a structure different from that of guanidine hydrochloride in the prior art, as shown below: , where the degree of polymerization n=60~100.

[0027] It can be seen from the above structural formula that a new structure is adopted for the guanidine hydrochloride in the present embodiment, and the methyl side chains of the 2-methylpentanediamine in its structure can destroy the linear symmetry of hexamethylenediamine, increase the spatial distribution density of the guanidine group, enhance the positive charge density, and enhance the adsorption capacity of the bacterial cell membrane, thereby improving the bactericidal efficiency, making it more efficient for the inactivation rate of Escherichia coli and Staphylococcus aureus compared to the guanidine hydrochloride in the prior art. Moreover, the crystallinity of the polymer can be reduced for its branched structure, making it easier for its final product to form a loose film layer, making it easier and more sufficient to combine with the nanoemulsion, and more able to promote the antibacterial component to penetrate to the outside to enhance the control of the deep position. Compared with existing guanidine hydrochloride, such as polyhexamethylene biguanide hydrochloride commonly used for broad-spectrum antibacterial use, the guanidine hydrochloride provided in this embodiment is more suitable for antibacterial use on the surface of human skin.

[0028] It's worth noting that some pathogenic bacteria, such as Staphylococcus aureus and Escherichia coli, produce acidic metabolites (lactic acid, acetic acid, etc.) during their growth, which can lead to a decrease in the environmental pH. Based on this characteristic, the applicant designed the antimicrobial material in this embodiment to be sensitive to acid. Specifically, this embodiment uses chitosan and tsaoko essential oil to form an acid-sensitive imine bond to construct an acid-sensitive antimicrobial material. This imine-bonded antimicrobial material exhibits advantages such as rapid in situ formation, self-repairing properties, lack of cytotoxicity, on-demand release of the active antimicrobial component, and excellent antimicrobial activity.

[0029] Compared with traditional release-type materials, the acid-sensitive antibacterial material proposed in this embodiment can intelligently sense changes in the external environment and release active substances in response to stimulation signals. In addition, the active substance in this embodiment adopts a newly synthesized guanidine hydrochloride, which can directly act on the human body surface and has a highly effective antibacterial effect. This assembly method can directly improve the utilization efficiency and antibacterial effect of antibacterial molecules.

[0030] Furthermore, gelatin, as a substructure, can directly come into contact with external objects. To impart antibacterial properties to the substructure and improve the performance of gelatin, tannic acid is incorporated into the gelatin solid material in this embodiment. Tannic acid is an ester formed by the combination of gallic acid or a phenolic acid related to gallic acid and a polyol. It has a relatively low molecular weight of 500-3000 Da, is highly hydrolyzable, soluble in water, and easily hydrolyzed by acids, alkalis, and enzymes. The polyphenolic hydroxyl structure of tannic acid possesses a series of unique chemical properties and physiological activities, such as a high affinity for proteins, the ability to combine with alkaloids and polysaccharides to undergo physical and chemical reactions that alter its properties, and the ability to undergo complexation and electrostatic interactions with various metal ions, showing reducing properties and the activity of capturing free radicals.

[0031] Tannic acid, as a plant polyphenol, can directly interact with gelatin through non-covalent bonds. First, it is oxidized to produce quinone compounds, and then the quinone compounds react with the amino acid residues of gelatin to obtain a chemical cross-linked film with good compatibility, which can be directly used as a natural cross-linking agent for gelatin to enhance the mechanical properties and thermal stability of gelatin. In addition, tannic acid itself has antioxidant, hemostatic and antibacterial activity, and can be directly attached to the wound surface on the human body surface, thereby improving the applicability of antibacterial materials to the human body. In addition, the side chains of the guanidine hydrochloride provided in this embodiment give the film layer high elasticity. The combination of the two makes the skin fit and breathability better than traditional excipients, thereby reducing the risk of skin immersion, and the branched structure of guanidine hydrochloride can enhance the interfacial bonding force with the substrate, thereby preventing the dressing from peeling off during exercise, and is more suitable for use in joints.

[0032] In summary, the antimicrobial material provided in this embodiment, by synthesizing a novel guanidine hydrochloride as the active ingredient, combined with the gated release mechanism of nanoemulsions and the strengthening effect of gelatin, demonstrates superior antimicrobial efficacy on human surfaces compared to existing antimicrobial materials. This material significantly enhances antimicrobial activity and exhibits higher biocompatibility. In skin applications, it overcomes the dissolution toxicity and physical property limitations of existing antimicrobial materials by enhancing interfacial bonding, reducing dissolution, promoting healing, and achieving gated release.

[0033] For the preparation method of the antibacterial material provided in this embodiment, please refer to Figure 1 The process shown includes the following steps:

[0034] Step S11. 22 wt% chitosan is dissolved in 1 wt% acid solution at a weight percentage ratio of 2:1, and the mixture is stirred for 2 h at 25°C to form a solution. The active component is added to the solution to form an intermediate solution, and the intermediate solution is centrifuged to remove bubbles in the solution.

[0035] In this embodiment, the acid solution includes glacial acetic acid.

[0036] The active component is guanidine hydrochloride, specifically poly-2-methyl-pentamethyleneguanidine hydrochloride, which has the following structural formula: , where the degree of polymerization n=60~100.

[0037] Specifically, for the novel polymer obtained by synthesizing poly-2-methyl-pentamethyleneguanidine hydrochloride through 2-methyl-1,5-pentanediamine and guanidine hydrochloride, the synthesis method of this polymer is described in detail. For the detailed synthesis process, please refer to Figure 2 , including the following steps:

[0038] Step S21. 2-methyl-1,5-pentanediamine and guanidine hydrochloride in a molar ratio of 1:1 are subjected to a multi-stage temperature increase reaction under a nitrogen atmosphere to obtain a polymer melt.

[0039] Among them, the multi-stage temperature rise reaction in this embodiment includes a three-stage temperature rise process, and the target temperatures of the three-stage temperature rise process, that is, the temperature rise cutoff temperatures, are 75°C~85°C, 115°C~125°C, and 175°C~185°C, respectively. In the first temperature rise stage, after the temperature rise is completed, the reactants are stirred for 15~30min to obtain the first-stage product. This process is the initial reaction stage used to disperse the substrate so that its subsequent reaction is more sufficient; the second temperature rise stage is based on the first-stage product. After the second temperature rise reaction is completed, reaction by-products will begin to be produced. The reaction by-products of this stage are mainly ammonia. In this process, ammonia needs to be discharged, and in order to control the rate of ammonia production when entering the third temperature rise stage, the temperature rise rate in this temperature rise stage should be uniform until the target temperature of the third temperature rise stage is reached and the temperature is stopped. After the temperature rise in the third temperature rise stage is completed, the reaction product is stirred for 2~3h to obtain the polymer melt.

[0040] Step S22. Pressing the polymer melt into purified water based on nitrogen pressure and stirring, dissolving, filtering, and collecting an aqueous solution containing crude 2-methyl-pentamethyleneguanidine hydrochloride.

[0041] In this process, the polymer melt obtained in step S21 is transferred from the reactor to a separation tank filled with purified water based on nitrogen pressure, and the impurities are dissolved by sufficient stirring, and the filtrate is collected by filtration. The obtained filtrate is an aqueous solution of the crude poly-2-methyl-pentamethyleneguanidine hydrochloride.

[0042] Step S23. Purify, concentrate, and dry the aqueous solution containing the crude 2-methyl-pentamethyleneguanidine hydrochloride by ion exchange to obtain the poly-2-methyl-pentamethyleneguanidine hydrochloride.

[0043] In this process, the aqueous solution of crude poly-2-methyl-pentamethyleneguanidine hydrochloride is purified twice through an ion exchange membrane, and the purified liquid is then concentrated and dried to obtain poly-2-methyl-pentamethyleneguanidine hydrochloride solid with a purity greater than or equal to 99%.

[0044] Furthermore, the reaction in step S21 is carried out in a reactor, and the reactions in steps S22-S23 are carried out in a separation tank. In the reactions of steps S21-S23, only 2-methyl-1,5-pentanediamine and guanidine hydrochloride are introduced, and no other reaction aids are introduced. Compared with the guanidine hydrochloride reaction process in the prior art, it is simpler, more efficient, and cleaner, avoiding the purity impact caused by the introduction of initiators and terminators.

[0045] Specifically, in this embodiment, a new type of guanidine hydrochloride can be obtained by adopting steps S21 to S23, and the yield of the poly-2-methyl-pentamethyleneguanidine hydrochloride obtained by the reaction is 96-99%, and the purity is greater than or equal to 99%.

[0046] Step S12: mixing and stirring the intermediate solution and the nanoemulsion in a weight ratio of (2-1): (1-2) to form a mixed solution, and mixing the mixed solution on a gelatin solid and drying it to obtain the antibacterial material.

[0047] In this embodiment, the nanoemulsion is obtained by mixing and stirring an oil phase with a concentration of 10% and an aqueous phase with a concentration of 90%, wherein the oil phase is obtained by ultrasonically mixing an emulsifier with a mass ratio of 5% to 10% of the oil phase and an essential oil with a mass ratio of 90% to 95% of the oil phase.

[0048] Specifically, in this embodiment, the essential oil is tsaoko essential oil, and the emulsifier is a mixed emulsifier obtained by mixing Tween 20 and sucrose fatty acid ester in equal proportions. The ultrasonic power ratio is 50% to 90%, and the ultrasonic time is 5 minutes to 25 minutes.

[0049] In this embodiment, to obtain the gelatin solution, first 2 wt% gelatin and 1 wt% glycerol are added to distilled water, and heated and stirred at 60°C to obtain an initial gelatin solution. 0.5 wt% to 5 wt% tannic acid is added to the initial gelatin solution and the solution is dissolved by accelerated stirring at 40°C to obtain the gelatin solution.

[0050] The gelatin solid is obtained by drying the gelatin solution at 35° C. for 4 hours.

[0051] The following is a detailed description of the method for preparing the antibacterial material of the present invention through specific examples.

[0052] Example 1

[0053] The present invention provides a method for preparing an antibacterial material, comprising the following steps:

[0054] Synthesis of active ingredients:

[0055] Step S11. While stirring, add 116.2 kg of 2-methyl-1,5-pentanediamine and 95.53 kg of guanidine hydrochloride to the reactor in sequence, seal the reactor and introduce nitrogen to protect the reaction with a nitrogen atmosphere, increase the temperature and continue stirring to 75°C, stir for 15 to 30 minutes to mix evenly, and obtain the first stage product.

[0056] Step S12: continue heating to 115° C., discharge the generated ammonia through a pipeline and collect it, and obtain an intermediate product.

[0057] Step S13: uniformly control the heating rate and raise the temperature to 175° C., stir and react for 2 h to obtain a polymer melt.

[0058] Step S14. The obtained polymer melt in a molten state is transferred from the reactor to a separation tank filled with purified water based on nitrogen pressure, fully stirred and dissolved, filtered and the filtrate is collected to obtain an aqueous solution of crude poly-2-methyl-pentamethyleneguanidine hydrochloride.

[0059] Step S15. The aqueous solution of poly-2-methyl-pentamethyleneguanidine hydrochloride is purified again through an ion exchange membrane, and the purified liquid is concentrated and dried to obtain a solid, i.e., 204 kg of poly-2-methyl-pentamethyleneguanidine hydrochloride with a purity of more than 99%.

[0060] Synthesis of nanoemulsion:

[0061] Step S21. Mix Tween 20 and sucrose fatty acid ester in equal proportions to obtain an emulsifier.

[0062] Step S22. Add 9 times by mass of tsaoko essential oil to the compounded emulsifier, and obtain an oil phase by ultrasonic treatment with an ultrasonic power ratio of 50% and an ultrasonic time of 25 min.

[0063] Step S23: The oil phase and distilled water were mixed and stirred at a concentration ratio of 1:9 for 15 minutes to obtain a nanoemulsion.

[0064] Synthesis of gelatin solid:

[0065] Step S31. Add 400 kg of 2 wt% gelatin and 200 kg of 1 wt% glycerol to 600 kg of distilled water, and heat and stir at 60° C. to obtain an initial gelatin solution.

[0066] Step S32: Add 0.5 wt% of tannic acid to the initial gelatin solution and dissolve it by accelerated stirring at 40°C to obtain a gelatin solution.

[0067] Step S33: Dry the gelatin solution at 35°C for 4 hours to obtain a gelatin solid.

[0068] Preparation of antibacterial materials:

[0069] Step S1. Dissolve 100 kg of 2 wt% chitosan in 50 kg of 1 wt% glacial acetic acid, stir thoroughly at 25°C for 2 hours to form a solution, add 25 kg of poly-2-methyl-pentamethyleneguanidine hydrochloride solid to the stirred solution to form an intermediate solution, and centrifuge the intermediate solution to remove bubbles in the solution.

[0070] Step S2. The intermediate solution and the nanoemulsion are mixed and stirred at a weight ratio of 2:1 to form a mixed solution, and the mixed solution is mixed on a gelatin solid and dried to obtain an antibacterial material.

[0071] Example 2

[0072] The present invention provides a method for preparing an antibacterial material, comprising the following steps:

[0073] Synthesis of active ingredients:

[0074] Step S11. While stirring, add 116.2 kg of 2-methyl-1,5-pentanediamine and 95.53 kg of guanidine hydrochloride to the reactor in sequence, seal the reactor and introduce nitrogen to protect the reaction with a nitrogen atmosphere, increase the temperature and continue stirring to 80°C, stir for 15 to 30 minutes to mix evenly, and obtain the first stage product.

[0075] Step S12: continue heating to 120° C., discharge the generated ammonia through a pipeline and collect it, and obtain an intermediate product.

[0076] Step S13: uniformly control the heating rate and raise the temperature to 180° C., stir and react for 2.2 h to obtain a polymer melt.

[0077] Step S14. The obtained polymer melt in a molten state is transferred from the reactor to a separation tank filled with purified water based on nitrogen pressure, fully stirred and dissolved, filtered and the filtrate is collected to obtain an aqueous solution of crude poly-2-methyl-pentamethyleneguanidine hydrochloride.

[0078] Step S15. The aqueous solution of poly-2-methyl-pentamethyleneguanidine hydrochloride is purified again through an ion exchange membrane, and the purified liquid is concentrated and dried to obtain a solid, i.e., 204.7 kg of poly-2-methyl-pentamethyleneguanidine hydrochloride with a purity of more than 99%.

[0079] Synthesis of nanoemulsion:

[0080] Step S21. Mix Tween 20 and sucrose fatty acid ester in equal proportions to obtain an emulsifier.

[0081] Step S22. Add 12 times the mass of tsaoko essential oil to the compounded emulsifier, and obtain an oil phase by ultrasonic treatment with an ultrasonic power ratio of 75% and an ultrasonic time of 15 minutes.

[0082] Step S23: The oil phase and distilled water were mixed and stirred at a concentration ratio of 1:9 for 15 minutes to obtain a nanoemulsion.

[0083] Synthesis of gelatin solid:

[0084] Step S31. Add 400 kg of 2 wt% gelatin and 200 kg of 1 wt% glycerol to 600 kg of distilled water, and heat and stir at 60° C. to obtain an initial gelatin solution.

[0085] Step S32: Add 1.5 wt% of tannic acid to the initial gelatin solution and dissolve it by accelerated stirring at 40°C to obtain a gelatin solution.

[0086] Step S33: Dry the gelatin solution at 35°C for 4 hours to obtain a gelatin solid.

[0087] Preparation of antibacterial materials:

[0088] Step S1. Dissolve 100 kg of 2 wt% chitosan in 50 kg of 1 wt% glacial acetic acid, stir thoroughly at 25°C for 2 hours to form a solution, add 25 kg of poly-2-methyl-pentamethyleneguanidine hydrochloride solid to the stirred solution to form an intermediate solution, and centrifuge the intermediate solution to remove bubbles in the solution.

[0089] Step S2: The intermediate solution and the nanoemulsion are mixed and stirred at a weight ratio of 2:2 to form a mixed solution, and the mixed solution is mixed on a gelatin solid and dried to obtain an antibacterial material.

[0090] Example 3

[0091] The present invention provides a method for preparing an antibacterial material, comprising the following steps:

[0092] Synthesis of active ingredients:

[0093] Step S11. While stirring, add 116.2 kg of 2-methyl-1,5-pentanediamine and 95.53 kg of guanidine hydrochloride to the reactor in sequence, seal the reactor and introduce nitrogen to protect the reaction with a nitrogen atmosphere, increase the temperature and continue stirring to 85°C, stir for 25 minutes to make it evenly stirred, and obtain the first stage product.

[0094] Step S12: continue heating to 125° C., discharge the generated ammonia through a pipeline and collect it, and obtain an intermediate product.

[0095] Step S13: uniformly control the heating rate and raise the temperature to 185° C., stir and react for 3 h to obtain a polymer melt.

[0096] Step S14. The obtained polymer melt in a molten state is transferred from the reactor to a separation tank filled with purified water based on nitrogen pressure, fully stirred and dissolved, filtered and the filtrate is collected to obtain an aqueous solution of crude poly-2-methyl-pentamethyleneguanidine hydrochloride.

[0097] Step S15. The aqueous solution of poly-2-methyl-pentamethyleneguanidine hydrochloride is purified again through an ion exchange membrane, and the purified liquid is concentrated and dried to obtain a solid, i.e., 205.1 kg of poly-2-methyl-pentamethyleneguanidine hydrochloride with a purity of more than 99%.

[0098] Synthesis of nanoemulsion:

[0099] Step S21. Mix Tween 20 and sucrose fatty acid ester in equal proportions to obtain an emulsifier.

[0100] Step S22. Add 15 times by mass of tsaoko essential oil to the compounded emulsifier, and obtain an oil phase by ultrasonic treatment with an ultrasonic power ratio of 80% and an ultrasonic time of 10 min.

[0101] Step S23: The oil phase and distilled water were mixed and stirred at a concentration ratio of 1:9 for 15 minutes to obtain a nanoemulsion.

[0102] Synthesis of gelatin solid:

[0103] Step S31. Add 400 kg of 2 wt% gelatin and 200 kg of 1 wt% glycerol to 600 kg of distilled water, and heat and stir at 60° C. to obtain an initial gelatin solution.

[0104] Step S32: Add 3 wt% of tannic acid to the initial gelatin solution and dissolve it by accelerated stirring at 40°C to obtain a gelatin solution.

[0105] Step S33: Dry the gelatin solution at 35°C for 4 hours to obtain a gelatin solid.

[0106] Preparation of antibacterial materials:

[0107] Step S1. Dissolve 100 kg of 2 wt% chitosan in 50 kg of 1 wt% glacial acetic acid, stir thoroughly at 25°C for 2 hours to form a solution, add 25 kg of poly-2-methyl-pentamethyleneguanidine hydrochloride solid to the stirred solution to form an intermediate solution, and centrifuge the intermediate solution to remove bubbles in the solution.

[0108] Step S2. The intermediate solution and the nanoemulsion are mixed and stirred at a weight ratio of 1:2 to form a mixed solution, and the mixed solution is mixed on a gelatin solid and dried to obtain an antibacterial material.

[0109] Example 4

[0110] The present invention provides a method for preparing an antibacterial material, comprising the following steps:

[0111] Synthesis of active ingredients:

[0112] Step S11. While stirring, add 116.2 kg of 2-methyl-1,5-pentanediamine and 95.53 kg of guanidine hydrochloride to the reactor in sequence, seal the reactor and introduce nitrogen to protect the reaction with a nitrogen atmosphere, increase the temperature and continue stirring to 75°C, stir for 30 minutes to make it evenly stirred, and obtain the first stage product.

[0113] Step S12: continue heating to 120° C., discharge the generated ammonia through a pipeline and collect it, and obtain an intermediate product.

[0114] Step S13: uniformly control the heating rate and raise the temperature to 180° C., stir and react for 2.5 hours to obtain a polymer melt.

[0115] Step S14. The obtained polymer melt in a molten state is transferred from the reactor to a separation tank filled with purified water based on nitrogen pressure, fully stirred and dissolved, filtered and the filtrate is collected to obtain an aqueous solution of crude poly-2-methyl-pentamethyleneguanidine hydrochloride.

[0116] Step S15. The aqueous solution of poly-2-methyl-pentamethyleneguanidine hydrochloride is purified again through an ion exchange membrane, and the purified liquid is concentrated and dried to obtain a solid, i.e., 205.8 kg of poly-2-methyl-pentamethyleneguanidine hydrochloride with a purity of more than 99%.

[0117] Synthesis of nanoemulsion:

[0118] Step S21. Mix Tween 20 and sucrose fatty acid ester in equal proportions to obtain an emulsifier.

[0119] Step S22. Add 19 times the mass of tsaoko essential oil to the compounded emulsifier, and obtain an oil phase by ultrasonic treatment with an ultrasonic power ratio of 90% and an ultrasonic time of 5 minutes.

[0120] Step S23: The oil phase and distilled water were mixed and stirred at a concentration ratio of 1:9 for 15 minutes to obtain a nanoemulsion.

[0121] Synthesis of gelatin solid:

[0122] Step S31. Add 400 kg of 2 wt% gelatin and 200 kg of 1 wt% glycerol to 600 kg of distilled water, and heat and stir at 60° C. to obtain an initial gelatin solution.

[0123] Step S32: Add 4 wt% of tannic acid to the initial gelatin solution and dissolve it by accelerated stirring at 40°C to obtain a gelatin solution.

[0124] Step S33: Dry the gelatin solution at 35°C for 4 hours to obtain a gelatin solid.

[0125] Preparation of antibacterial materials:

[0126] Step S1. Dissolve 100 kg of 2 wt% chitosan in 50 kg of 1 wt% glacial acetic acid, stir thoroughly at 25°C for 2 hours to form a solution, add 25 kg of poly-2-methyl-pentamethyleneguanidine hydrochloride solid to the stirred solution to form an intermediate solution, and centrifuge the intermediate solution to remove bubbles in the solution.

[0127] Step S2. The intermediate solution and the nanoemulsion are mixed and stirred at a weight ratio of 2:1 to form a mixed solution, and the mixed solution is mixed on a gelatin solid and dried to obtain an antibacterial material.

[0128] Example 5

[0129] The present invention provides a method for preparing an antibacterial material, comprising the following steps:

[0130] Synthesis of active ingredients:

[0131] Step S11. While stirring, add 116.2 kg of 2-methyl-1,5-pentanediamine and 95.53 kg of guanidine hydrochloride to the reactor in sequence, seal the reactor and introduce nitrogen to protect the reaction with a nitrogen atmosphere, increase the temperature and continue stirring to 85°C, stir for 30 minutes to make it evenly stirred, and obtain the first stage product.

[0132] Step S12: continue heating to 125° C., discharge the generated ammonia through a pipeline and collect it, and obtain an intermediate product.

[0133] Step S13: uniformly control the heating rate and raise the temperature to 185° C., stir and react for 2 h to obtain a polymer melt.

[0134] Step S14. The obtained polymer melt in a molten state is transferred from the reactor to a separation tank filled with purified water based on nitrogen pressure, fully stirred and dissolved, filtered and the filtrate is collected to obtain an aqueous solution of crude poly-2-methyl-pentamethyleneguanidine hydrochloride.

[0135] Step S15. The aqueous solution of poly-2-methyl-pentamethyleneguanidine hydrochloride is purified again through an ion exchange membrane, and the purified liquid is concentrated and dried to obtain a solid, i.e., 206.5 kg of poly-2-methyl-pentamethyleneguanidine hydrochloride with a purity of more than 99%.

[0136] Synthesis of nanoemulsion:

[0137] Step S21. Mix Tween 20 and sucrose fatty acid ester in equal proportions to obtain an emulsifier.

[0138] Step S22. Add 9 to 19 times by mass of tsaoko essential oil to the compounded emulsifier, and obtain an oil phase by ultrasonic treatment with an ultrasonic power ratio of 50% and an ultrasonic time of 25 min.

[0139] Step S23: The oil phase and distilled water were mixed and stirred at a concentration ratio of 1:9 for 15 minutes to obtain a nanoemulsion.

[0140] Synthesis of gelatin solid:

[0141] Step S31. Add 400 kg of 2 wt% gelatin and 200 kg of 1 wt% glycerol to 600 kg of distilled water, and heat and stir at 60° C. to obtain an initial gelatin solution.

[0142] Step S32: Add 0.5 wt% of tannic acid to the initial gelatin solution and dissolve it by accelerated stirring at 40°C to obtain a gelatin solution.

[0143] Step S33: Dry the gelatin solution at 35°C for 4 hours to obtain a gelatin solid.

[0144] Preparation of antibacterial materials:

[0145] Step S1. Dissolve 100 kg of 2 wt% chitosan in 50 kg of 1 wt% glacial acetic acid, stir thoroughly at 25°C for 2 hours to form a solution, add 25 kg of poly-2-methyl-pentamethyleneguanidine hydrochloride solid to the stirred solution to form an intermediate solution, and centrifuge the intermediate solution to remove bubbles in the solution.

[0146] Step S2. The intermediate solution and the nanoemulsion are mixed and stirred at a weight ratio of 1:1 to form a mixed solution, and the mixed solution is mixed on a gelatin solid and dried to obtain an antibacterial material.

[0147] Example 6

[0148] The present invention provides a method for preparing an antibacterial material, comprising the following steps:

[0149] Synthesis of active ingredients:

[0150] Step S11. While stirring, add 116.2 kg of 2-methyl-1,5-pentanediamine and 95.53 kg of guanidine hydrochloride to the reactor in sequence, seal the reactor and introduce nitrogen to protect the reaction with a nitrogen atmosphere, increase the temperature and continue stirring to 75°C, stir for 30 minutes to make it evenly stirred, and obtain the first stage product.

[0151] Step S12: continue heating to 115° C., discharge the generated ammonia through a pipeline and collect it, and obtain an intermediate product.

[0152] Step S13: uniformly control the heating rate and raise the temperature to 175° C., stir and react for 3 h to obtain a polymer melt.

[0153] Step S14. The obtained polymer melt in a molten state is transferred from the reactor to a separation tank filled with purified water based on nitrogen pressure, fully stirred and dissolved, filtered and the filtrate is collected to obtain an aqueous solution of crude poly-2-methyl-pentamethyleneguanidine hydrochloride.

[0154] Step S15. The aqueous solution of poly-2-methyl-pentamethyleneguanidine hydrochloride is purified again through an ion exchange membrane, and the purified liquid is concentrated and dried to obtain a solid, i.e., 204.4 kg of poly-2-methyl-pentamethyleneguanidine hydrochloride with a purity of more than 99%.

[0155] Synthesis of nanoemulsion:

[0156] Step S21. Mix Tween 20 and sucrose fatty acid ester in equal proportions to obtain an emulsifier.

[0157] Step S22. Add 15 times by mass of tsaoko essential oil to the compounded emulsifier, and obtain an oil phase by ultrasonic treatment with an ultrasonic power ratio of 75% and an ultrasonic time of 10 min.

[0158] Step S23: The oil phase and distilled water were mixed and stirred at a concentration ratio of 1:9 for 15 minutes to obtain a nanoemulsion.

[0159] Synthesis of gelatin solid:

[0160] Step S31. Add 400 kg of 2 wt% gelatin and 200 kg of 1 wt% glycerol to 600 kg of distilled water, and heat and stir at 60° C. to obtain an initial gelatin solution.

[0161] Step S32: Add 4.5 wt% of tannic acid to the initial gelatin solution and dissolve it by accelerated stirring at 40°C to obtain a gelatin solution.

[0162] Step S33: Dry the gelatin solution at 35°C for 4 hours to obtain a gelatin solid.

[0163] Preparation of antibacterial materials:

[0164] Step S1. Dissolve 100 kg of 2 wt% chitosan in 50 kg of 1 wt% glacial acetic acid, stir thoroughly at 25°C for 2 hours to form a solution, add 25 kg of poly-2-methyl-pentamethyleneguanidine hydrochloride solid to the stirred solution to form an intermediate solution, and centrifuge the intermediate solution to remove bubbles in the solution.

[0165] Step S2. The intermediate solution and the nanoemulsion are mixed and stirred at a weight ratio of 1:2 to form a mixed solution, and the mixed solution is mixed on a gelatin solid and dried to obtain an antibacterial material.

[0166] Experimental Example 1

[0167] The antibacterial materials corresponding to Examples 1 to 6 were selected to realize pH response and controlled release performance. The antibacterial materials corresponding to Examples 1 to 6 were immersed in ethanol aqueous solutions with pH values ​​of 6.0 and 7.0, respectively, to conduct release tests. The release results can be found in Figure 3 shown.

[0168] for Figure 3-1 Figures AC in the figure are the release curves of Examples 1 to 3 under pH 6.0 conditions, Figure 3-2 The GI figures in the figure are the release curves of Examples 4 to 6 at pH 6.0; Figure 3-1 Figures DF in the figure are release curves of Examples 1 to 3 under pH 7.0 conditions, Figure 3-2 The JL figures in the figure are the release curves of Examples 4 to 6 under pH 7.0 conditions, respectively. As can be seen from the above figures, the release rate of the antibacterial material in the acidic environment is high in the initial release stage, and the release rate increases with the increase of the nanoemulsion content in the antibacterial material. After about 4 hours, the release rate of each antibacterial material gradually slows down and eventually reaches equilibrium. Moreover, the time required to reach equilibrium is positively correlated with the content of nanoemulsion, which indicates that the increase of nanoemulsion can promote the cross-linking of the matrix, increase the sustained-release performance and thus obtain longer antibacterial activity. Moreover, as can be seen from the results in Figures DF, the antibacterial material hardly releases nanoemulsion in the central environment.

[0169] Experimental Example 2

[0170] See Figure 4 In order to determine the experimental results of the antibacterial properties of the antibacterial materials obtained by the preparation methods disclosed in Examples 1 to 6 using the inhibition zone method, the antibacterial activity of Examples 1 to 6 against two bacteria was determined using the paper disc diffusion method, where the bacteria were Escherichia coli and Staphylococcus aureus, respectively.

[0171] Take 200 μL of the solution with a concentration of 1×10 6A bacterial suspension of 100 CFU / mL was evenly spread on LB nutrient agar plates using a sterile applicator. Three drug-sensitive paper sheets were placed on each culture dish. The antimicrobial materials corresponding to Examples 1-6 were placed on the drug-sensitive paper sheets. The culture dishes were placed in a 37°C constant temperature incubator, and the antimicrobial materials were removed and the diameter of the inhibition zone was measured.

[0172] Among them, Figures af are the experimental results of the antibacterial material obtained by the preparation method corresponding to Examples 1 to 6 for the Escherichia coli inhibition zone method, and Figure jl is the experimental results of the antibacterial material obtained by the preparation method corresponding to Examples 1 to 6 for the Staphylococcus aureus inhibition zone method.

[0173] pass Figure 4 The inhibition zone radii shown in the various figures show that the inhibition zone radius is larger than the diagonal line of the antibacterial material, indicating that the antibacterial material can inhibit Escherichia coli and Staphylococcus aureus within the area. Furthermore, the inhibition zone radii corresponding to the figures above show that the higher the nanoemulsion content, the larger the corresponding inhibition radius, indicating that a higher concentration of the active ingredient has a stronger destructive effect on bacteria.

[0174] Comparative Example

[0175] See Figure 5 , which is an illustration of the antibacterial effect obtained by using two commercially available antibacterial materials to perform the inhibition zone method in the prior art. Figure 5 It can be seen that the antibacterial effects of the two commercially available antibacterial materials on Escherichia coli and Staphylococcus aureus are lower than those of the antibacterial materials prepared in any of Examples 1 to 6.

[0176] With respect to the preparation method and application of an antibacterial material provided in Examples 1 to 6, a novel antibacterial material for disinfecting wounds and wounds on the human body is provided. A novel guanidine hydrochloride, a nanoemulsion, and a gelatin solid are synthesized separately, and a multi-stimulus responsive double-layer antibacterial material is obtained based on the assembly of gelatin. This double-layer antibacterial material has a pH gating mechanism that can increase the pH sensitivity of the antibacterial material, slowly release the active material under pH conditions, and enhance the antibacterial effect through the synthesized novel guanidine hydrochloride. Compared with existing technologies, it has higher antibacterial properties and human applicability.

[0177] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing an antibacterial material, characterized in that: The method comprises the following steps: 2 wt% chitosan was dissolved in 1 wt% acid solution at a weight percentage ratio of 2:1, and the mixture was stirred for 2 h at 25° C. to form a solution. An active component was added to the solution to form an intermediate solution, and the intermediate solution was centrifuged to remove bubbles in the solution. The active component was poly-2-methyl-pentamethyleneguanidine hydrochloride, which has the following structural formula: , where the degree of polymerization n=60~100; The intermediate solution and the nanoemulsion are mixed and stirred in a weight ratio of (2~1): (1~2) to form a mixed solution, and the mixed solution is mixed on a gelatin solid and dried to obtain the antibacterial material; the antibacterial material has a double-layer structure, the first layer is a gelatin solid formed by drying the gelatin solution, and the second layer is an active substance formed by drying the active component and the nanoemulsion with chitosan as a carrier, and the active substance is wrapped in the gelatin solid; chitosan is used as a carrier through the chitosan solid The amino group of the nanoemulsion is combined with the nanoemulsion to form an imine bond. The nanoemulsion is obtained by mixing and stirring an oil phase with a concentration of 10% and an aqueous phase with a concentration of 90%. The oil phase is obtained by ultrasonically combining an emulsifier with a mass ratio of 5% to 10% of the oil phase and an essential oil with a mass ratio of 90% to 95% of the oil phase; the ultrasonic power ratio is 50% to 90%, and the ultrasonic time is 5 minutes to 25 minutes. The essential oil is tsaoko essential oil, and the emulsifier is obtained by mixing two emulsifiers, Tween 20 and sucrose fatty acid ester, in equal proportions.

2. The method for preparing an antibacterial material according to claim 1, wherein: The gelatin solution is obtained by adding 2 wt% gelatin and 1 wt% glycerol to distilled water, and heating and stirring the mixture at 60°C to obtain an initial gelatin solution; adding 0.5 wt% to 5 wt% tannic acid to the initial gelatin solution and accelerating the stirring and dissolving the mixture at 40°C to obtain the gelatin solution; and the gelatin solid is obtained by drying the gelatin solution at 35°C for 4 hours.

3. The method for preparing an antibacterial material according to claim 1, wherein: The poly-2-methyl-pentamethyleneguanidine hydrochloride is obtained by synthesizing 2-methyl-1,5-pentanediamine and guanidine hydrochloride.

4. The method for preparing an antibacterial material according to claim 3, characterized in that: The preparation method of the poly-2-methyl-pentamethyleneguanidine hydrochloride specifically includes: subjecting 2-methyl-1,5-pentanediamine and guanidine hydrochloride in a molar ratio of 1:1 to a multi-stage temperature increase reaction under nitrogen atmosphere conditions to obtain a polymer melt; the multi-stage temperature increase reaction includes a first temperature increase reaction stage, a second temperature increase reaction stage, and a third temperature increase reaction stage, wherein the target temperature range of the first temperature increase reaction stage is 75°C to 85°C, the target temperature range of the second temperature increase reaction stage is 115°C to 125°C, and the target temperature range of the third temperature increase reaction stage is 175°C to 185°C.

5. The method for preparing an antibacterial material according to claim 4, characterized in that: The preparation method of the poly-2-methyl-pentamethyleneguanidine hydrochloride further includes: pressing the polymer melt into purified water based on nitrogen pressure and stirring, dissolving, and filtering to collect an aqueous solution containing a crude 2-methyl-pentamethyleneguanidine hydrochloride product; and purifying, concentrating, and drying the aqueous solution containing the crude 2-methyl-pentamethyleneguanidine hydrochloride product through ion exchange to obtain the poly-2-methyl-pentamethyleneguanidine hydrochloride.

6. The method for preparing an antibacterial material according to claim 4, characterized in that: After the first temperature rising reaction stage is completed, stirring is performed for 15 to 30 minutes to obtain the first stage product; in the second temperature rising reaction stage, based on the completion of the first stage product heating, the ammonia in the reaction process is removed and collected to obtain the intermediate product; in the third temperature rising reaction stage, based on the completion of the intermediate product heating, the reactants are stirred for 2 to 3 hours to obtain the polymer melt.

7. The method for preparing an antibacterial material according to claim 4, characterized in that: The purity of the poly-2-methyl-pentamethyleneguanidine hydrochloride is greater than or equal to 99%.

8. The method for preparing an antibacterial material according to claim 1, characterized in that: The acid solution includes glacial acetic acid.

9. Use of the antibacterial material prepared by the method according to any one of claims 1 to 8 in medical dressings.

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