Nano-silver antibacterial agent as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of antibacterial materials, and particularly relates to a nano-silver antibacterial agent, which is prepared from the following raw materials in parts by weight: 85 to 95 parts of nano-silver solution, 0.5 to 1 part of plant extract and 2 to 6 parts of carboxymethyl glucan. The invention further discloses a preparation method and application of the nano-silver antibacterial agent. The antibacterial agent is good in stability, the preparation process is environment-friendly and pollution-free, the preparation method is simple, and the antibacterial agent has an excellent sterilization effect and also has a certain inhibition effect on the growth of cancer cells.

Description

Technical Field

[0001] The invention belongs to the technical field of antibacterial materials, and particularly relates to a nano silver antibacterial agent and a preparation method thereof. Background Art

[0002] Currently, alcohol is the most common disinfectant for skin surfaces. Disinfecting open wounds with alcohol-based products can damage surrounding tissue and slow wound healing. Studies have also shown that frequent use of alcohol-based disinfectants can lead to antibiotic resistance. Therefore, it is crucial to develop a mild, non-toxic, and non-irritating antimicrobial agent with effective antibacterial and sterilization properties.

[0003] Nanosilver particles are also a promising antimicrobial agent. Due to their excellent antimicrobial efficacy and high safety, they have been a focus of research in antimicrobial materials in recent years. Patent number CN113797290A, "An Antimicrobial Hydrogel and Its Preparation Method," discloses an antimicrobial hydrogel and its preparation method. The antimicrobial hydrogel comprises the following components: a nanosilver antimicrobial agent, a plant extract composition, an emulsifier, a gelling agent, and water; the plant extract composition is a combination of gallnut extract, cinnamon oil, lemongrass leaf oil, white jasmine oil, and gardenia extract. By combining the plant extract composition with the nanosilver antimicrobial agent, the antimicrobial hydrogel achieves a synergistic effect, resulting in enhanced antimicrobial efficacy while reducing the amount of nanosilver antimicrobial agent used, thus saving costs. However, the nanosilver antimicrobial agent in this invention requires the addition of a large number of additives to improve product stability, and the production process is cumbersome. Patent number CN112609208B, "A Method for Electrolytically Preparing a Low-Concentration Nanosilver Antibacterial Spray," discloses a method for preparing a nanosilver antibacterial agent using electrolysis. By varying the electrolysis voltage and current, the mobile phase throughput rate, and the stirring rate, the invention provides a method for producing a nanosilver aqueous solution with varying particle sizes and surface charges for use as an antibacterial spray. The use of sodium citrate as a stabilizer and pure silver electrodes avoids the use of silver nitrate as a starting material, thereby enhancing the biocompatibility of the nanosilver aqueous solution. However, the electrolytic reaction apparatus in this invention is complex and inconvenient to operate, and the invention does not provide relevant sterilization data. Summary of the Invention

[0004] The present invention aims to solve the above technical problems and provide a nano silver antibacterial agent with good stability and a green and pollution-free preparation process.

[0005] The technical solution of the present invention is:

[0006] A nano silver antibacterial agent is composed of the following raw materials in parts by weight: 85-95 parts of nano silver solution, 0.5-1 part of plant extract, and 2-6 parts of carboxymethyl dextran.

[0007] Preferably, the volume concentration of the nanosilver solution of the present invention is 6%, and the particle size of the nanosilver is 5nm to 15nm. The smaller the average particle size of the silver particles, the larger the surface area, and the greater the effect of the specific surface chemical composition. However, if the particles are too small, they will lose stability and may produce other interactions with other ions in the environment, thereby negatively affecting the product. The silver compounds invented in this product have excellent performance and are basically very stable in pure water without surfactants, etc. In addition, these materials are basically colorless, while other colloidal silver preparations (especially those with larger particle sizes) usually show color.

[0008] Preferably, the plant extract of the present invention is artemisinin. The addition of artemisinin not only significantly enhances the bactericidal ability, but also effectively inhibits the aggregation of nano silver ions and improves product stability.

[0009] In order to obtain the nano silver solution, preferably, the preparation method of the nano silver solution of the present invention comprises the following steps:

[0010] S1. Clean and dry two 99.99% pure silver electrodes.

[0011] S2. Place the dried silver electrode in a sealed electrolytic cell with a stirrer and add ultrapure water;

[0012] S3. Electrolyze to obtain nanosilver solution.

[0013] Preferably, during electrolysis, the initial voltage is 45V and the constant current is 1-2.0mA. The lower the electrolysis voltage, the larger the size of the electrolyzed silver particles, the more visible light absorbed, and the darker the color. If the voltage exceeds 45V, the size of the electrolyzed nanosilver particles will be smaller, but the energy consumed will be greater, which is uneconomical and environmentally unfavorable. To obtain a colorless, transparent nanoscale silver solution, the initial voltage must be properly controlled during electrolysis.

[0014] Preferably, after the electrolysis is started, the silver ion concentration is sampled and tested every 1 minute until the concentration of the nanosilver solution reaches 6%.

[0015] Preferably, the method for preparing the nano-silver antibacterial agent of the present invention comprises the following steps: uniformly mixing the nano-silver solution, the plant extract, and the carboxymethyl dextran, and stirring the mixture for 20 to 30 minutes to obtain the nano-silver antibacterial agent. The method of the present invention is simple and easy to operate.

[0016] The nano-silver antimicrobial agent of the present invention is used in the preparation of anticancer drugs. At a certain concentration, the prepared antimicrobial agent has no adverse effects on human cells and has a certain inhibitory effect on the growth of cancer cells. It has great application potential in the fields of medical treatment, health and so on.

[0017] Due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0018] 1. In the present invention, the addition of an appropriate amount of artemisinin not only significantly enhances the bactericidal ability, but also effectively inhibits the aggregation of nanosilver ions, making the product stability even better. In addition, carboxymethyl glucan (CM-glucan), a modified β-glucan with enhanced water solubility, not only protects the skin from UVA damage, but also accelerates the healing process of wounds, giving the product more practical functions.

[0019] 2. The silver particles produced by the method of the present invention have a particle size of only 5 to 15 nanometers, which is very small and does not produce color development. In addition, they are extremely stable and can be applied in many fields, effectively expanding the scope of application.

[0020] 3. The method of the present invention is simple, greatly reduces energy loss, provides convenient conditions for industrial large-scale production, and has extremely high industrial promotion value.

[0021] 4. Through a large number of experiments, the present invention has accurately determined the optimal concentration of nanosilver. The antibacterial agent prepared exhibits excellent bactericidal effect, has no adverse effects on human cells, and has a certain inhibitory effect on the growth of cancer cells. It has great application potential in the fields of medicine, health, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The electron microscope scanning images of the antibacterial agents obtained in Example 1 of the present invention and Comparative Example 1 are shown.

[0023] Figure 2 This is a graph showing the effects of the antibacterial agent of Example 1 of the present invention on human cells and cancer cells (A431). DETAILED DESCRIPTION

[0024] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0025] In the following embodiments:

[0026] Artemisinin was purchased from Xi'an Yanhao Biotechnology Co., Ltd.

[0027] Example 1

[0028] A nano silver antibacterial agent is composed of the following raw materials in parts by weight: 85 parts of nano silver solution, 0.5 parts of artemisinin, and 2 parts of carboxymethyl dextran.

[0029] The preparation method of the nano silver antibacterial agent comprises the following steps:

[0030] S1. Clean two 99.99% pure silver electrodes with anhydrous ethanol and dry them.

[0031] S2. Place the silver electrode in a sealed electrolytic cell with a stirrer and add an appropriate amount of ultrapure water;

[0032] S3. Set the initial voltage to 45V and the constant current to 2.0mA;

[0033] S4. Electrolyze at room temperature for more than 3 hours, sampling and testing the silver ion concentration every 1 minute;

[0034] S5. After the volume concentration of the nanosilver solution in the electrolytic cell reached 6%, the solution was pumped out into the reactor in parts by weight;

[0035] S6. Artemisinin and carboxymethyl dextran were added to the reaction kettle in parts by weight and stirred for 30 minutes to obtain the nanosilver antibacterial agent.

[0036] Example 2

[0037] A nano silver antibacterial agent is composed of the following raw materials in parts by weight: 90 parts of nano silver solution, 0.75 parts of artemisinin, and 4 parts of carboxymethyl dextran.

[0038] The preparation method of the nano silver antibacterial agent comprises the following steps:

[0039] S1. Clean two 99.99% pure silver electrodes with anhydrous ethanol and dry them.

[0040] S2. Place the silver electrode in a sealed electrolytic cell with a stirrer and add an appropriate amount of ultrapure water;

[0041] S3. Set the initial voltage to 45V and the constant current to 2.0mA;

[0042] S4. Electrolyze at room temperature for more than 3 hours, sampling and testing the silver ion concentration every 1 minute;

[0043] S5. After the volume concentration of the nanosilver solution in the electrolytic cell reached 6%, the solution was pumped out into the reactor in parts by weight;

[0044] S6. Artemisinin and carboxymethyl dextran were added to the reaction kettle according to weight, and the mixture was stirred for 20 minutes to obtain the nanosilver antibacterial agent.

[0045] Example 3

[0046] A nano silver antibacterial agent comprises the following components in parts by weight: 90 parts of nano silver solution, 1 part of artemisinin and 6 parts of carboxymethyl dextran.

[0047] The preparation method of the nano silver antibacterial agent comprises the following steps:

[0048] S1. Clean two 99.99% pure silver electrodes with anhydrous ethanol and dry them.

[0049] S2. Place the silver electrode in a sealed electrolytic cell with a stirrer and add an appropriate amount of ultrapure water;

[0050] S3. Set the initial voltage to 45V and the constant current to 1-2.0mA;

[0051] S4. Electrolyze at room temperature for more than 3 hours, sampling and testing the silver ion concentration every 1 minute;

[0052] S5. After the volume concentration of the nanosilver solution in the electrolytic cell reached 6%, the solution was pumped out into the reactor in parts by weight;

[0053] S6. Add artemisinin and carboxymethyl dextran according to weight into the reaction kettle and stir for 25 minutes to obtain the nanosilver antibacterial agent.

[0054] In order to verify the excellence of the nano silver antibacterial agent formula of the present invention, the following comparative examples are set up, as follows:

[0055] Comparative Example 1: The difference from Example 1 is that the initial voltage is set to 20V, and the rest is the same as Example 1.

[0056] Comparative Example 2: The difference from Example 1 is that the concentration of nanosilver is 1%, and the rest is the same as Example 1.

[0057] Comparative Example 3: The difference from Example 1 is that the concentration of nanosilver is 2%, and the rest is the same as Example 1.

[0058] Comparative Example 4: The difference from Example 1 is that the concentration of nanosilver is 3%, and the rest is the same as Example 1.

[0059] Comparative Example 5: The difference from Example 1 is that the concentration of nanosilver is 4%, and the rest is the same as Example 1.

[0060] Comparative Example 6: The difference from Example 1 is that the concentration of nanosilver is 5%, and the rest is the same as Example 1.

[0061] Comparative Example 7: The difference from Example 1 is that it does not contain carboxymethyl dextran, and the rest is the same as Example 1.

[0062] Comparative Example 8: The difference from Example 1 is that it does not contain artemisinin, and the rest is the same as Example 1.

[0063] Comparative Example 9: The difference from Example 1 is that it does not contain artemisinin and carboxymethyl glucan, and the rest is the same as Example 1.

[0064] Comparative Example 10: The difference from Example 1 is that artemisinin is replaced with forsythiaside.

[0065] Comparative Example 11: The difference from Example 1 is that carboxymethyl dextran is replaced by dextran.

[0066] Test Example 1: The above Example 1 and the comparative example were tested, and the results are as follows:

[0067] The antibacterial agents obtained in Example 1 and Comparative Example 1 were scanned by electron microscope, and the results were as follows: Figure 1 As shown. Figure 1 It can be seen that the smaller the electrolysis voltage, the larger the size of the electrolyzed silver particles, the more visible light they absorb, and the darker the color. In order to obtain nano-scale silver solution, the initial test voltage needs to be controlled during electrolysis.

[0068] Test Example 2: Antibacterial performance test was conducted on Example 1 and Comparative Examples 2-6. The test method was as follows:

[0069] S1. Place 9.9 ml of the antimicrobial agent in a sterile test tube and place the tube in a 20°C curing chamber.

[0070] S2. Place the bacterial strain into the sterile test tube in S1 and incubate the test tube in a 20°C incubator.

[0071] After 3.5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, and 20 hours, add one milliliter of the bacterial / antimicrobial suspension to a test tube containing 9 milliliters of neutralizer and mix the test tube thoroughly;

[0072] S4. After two minutes, dilute the neutralized suspension with saline at a ratio of 1:10.

[0073] S5. Determine the number of viable organisms in the selected dilution tubes by membrane filtration. Take duplicate one-ml aliquots. Rinse the filter with approximately 100 ml of sterile saline and transfer to a nutrient agar plate. Incubate the plate at 37°C in a humidified incubator for 20 hours.

[0074] S6. Count the number of colonies on each filter membrane and calculate the log reduction rate. The results are as follows:

[0075] Table 1

[0076]

[0077] Table 2

[0078]

[0079] Table 3

[0080]

[0081] Table 4

[0082]

[0083]

[0084] From Tables 1 to 4, we can see that when the concentration of colloidal silver is 6%, the sterilization effect is rapid and effective. If the concentration is too high, it will not only increase the cost but also cause certain harm to the human body.

[0085] Test Example 3: In order to explore the effect of the antibacterial agent of Example 1 of the present invention on human cells and cancer cells (A431) when the volume concentration of the nanosilver solution is 6%, the experimenters used sterile water and the antibacterial agent of Example 1 at a volume concentration of 6% of the nanosilver solution as the medium for testing. The test method is as follows:

[0086] S1. Place 9.9 ml aliquots of each of the two antimicrobial agents and two sterile water into sterile test tubes and equilibrate the tubes in a 20°C water bath.

[0087] S2. Place normal cells and cancer cells into sterile test tubes in S1 and place the test tubes in a 20°C water bath.

[0088] S3. After 24 hours, take 1 ml of S2 suspension into a test tube containing 9 ml of neutralizer and mix the test tube thoroughly;

[0089] S4. After two minutes, dilute the neutralized suspension with saline at a ratio of 1:10.

[0090] S5. Determine the number of viable cells in the selected dilution tubes by membrane filtration. Take duplicate 1-ml aliquots. Rinse the filter with approximately 100 ml of sterile saline and transfer to a nutrient agar plate. Incubate the plate at 37°C for 20 hours.

[0091] S6. Count the number of cells on each filter and calculate the cell viability.

[0092] The results are shown in Figure 2 .

[0093] from Figure 2 The experimental data clearly demonstrates that, in the presence of sterile water and a 6% concentration of nanosilver in Example 1, normal human cells continued to divide and grow normally. However, due to the high susceptibility of cancer cells (A431) and their dependence on a limited number of enzymes, the nanosilver antimicrobial exhibited a more significant inhibitory effect on them, highlighting their potential value in anticancer applications.

[0094] Test Example 4: Example 1 and Comparative Examples 7-8 were tested. The effects of the nanosilver antibacterial agent on Escherichia coli and Staphylococcus aureus were as follows:

[0095] Table 5

[0096]

[0097]

[0098] As shown in Figure 5, the antibacterial effect of nanosilver antibacterial agent is improved after adding artemisinin and carboxymethyl dextran.

[0099] Test Example 5: Stability tests were conducted on Example 1, Example 2, Example 3 and Comparative Example 9. The results are shown in Table 6:

[0100] Table 6

[0101]

[0102] Test Example 6: Stability tests were conducted on Example 1, Comparative Example 10, and Comparative Example 11. The results are shown in Table 7:

[0103] Table 7

[0104]

[0105] As can be seen from Tables 6 and 7, artemisinin and carboxymethyl dextran help improve the stability of nanosilver antimicrobial agents. In a colloidal system, a single small colloidal silver particle has a large specific surface area, so when interacting with other substances in the system, it reacts more violently, making it very easy to lose stability. In the present invention, the innovative addition of artemisinin and carboxymethyl dextran not only significantly improves the antibacterial efficacy of the antimicrobial agent, but also effectively increases the particle size structure of the system, thereby significantly enhancing the stability of the system.

[0106] Artemisinin mainly produces free radicals, destroying the biofilm of malarial parasites, thereby achieving antimalarial effects. This unique mechanism of action makes it less susceptible to oxidative mutation. In the present invention, an attempt was made to add artemisinin to an antibacterial agent. Through testing, it was found that it also has excellent antibacterial effects and high stability.

[0107] Carboxymethyl dextran has good water solubility and dissolves quickly in water to form a uniform solution. This facilitates better mixing with other ingredients and evenly dispersing the nanosilver particles during the preparation of nanosilver antimicrobial agents. However, dextran can only dissolve in some acidic solutions and has poor solubility under neutral and alkaline conditions. Therefore, when used in antimicrobial agents, its antimicrobial stability is poor.

[0108] In summary, the unique formulation and preparation method of the present invention have been combined to successfully produce a nanosilver antimicrobial agent. This antimicrobial agent effectively overcomes the numerous challenges faced by traditional products, including poor stability, limited application scenarios, complex ingredients, and low antimicrobial efficiency. Furthermore, the product of the present invention possesses a high degree of industrial feasibility, achieving zero emissions and pollution-free production throughout the entire process, conforming to the concept of green production and possessing broad market prospects and application value.

[0109] The above description is a detailed description of the preferred embodiments of the present invention, but the embodiments are not intended to limit the scope of the patent application of the present invention. Any equivalent changes or modifications completed under the technical spirit suggested by the present invention should fall within the patent scope covered by the present invention.

Claims

1. A nano silver antibacterial agent, characterized in that: The invention is composed of the following raw materials in parts by weight: 85-95 parts of nano silver solution, 0.5-1 part of plant extract and 2-6 parts of carboxymethyl dextran.

2. The nano silver antibacterial agent according to claim 1, wherein: The volume concentration of the nanosilver solution is 6%.

3. The nano silver antibacterial agent according to claim 1, wherein: The particle size of the nanosilver is 5nm to 15nm.

4. The nano silver antibacterial agent according to claim 1, wherein: The plant extract is artemisinin.

5. The nano silver antibacterial agent according to claim 1, wherein The preparation method of the nano silver solution comprises the following steps: S1. Clean and dry two 99.99% pure silver electrodes. S2. The dried silver electrode was placed in a sealed electrolytic cell with a stirrer and ultrapure water was added; S3. Electrolyze to obtain nanosilver solution.

6. The nano silver antibacterial agent according to claim 5, wherein: During electrolysis, the initial voltage was 45 V and the constant current was 1 to 2.0 mA.

7. The nano silver antibacterial agent according to claim 5, wherein: After the electrolysis started, samples were taken every 1 minute to test the silver ion concentration until the concentration of the nanosilver solution reached 6%.

8. The method for preparing the nano silver antibacterial agent according to any one of claims 1 to 7, wherein: The method comprises the following steps: uniformly mixing nano silver solution, plant extract and carboxymethyl dextran, stirring and reacting for 20 to 30 minutes to obtain the nano silver antibacterial agent.

9. Use of the nano silver antibacterial agent according to any one of claims 1 to 7 in the preparation of anticancer drugs.

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