Antibacterial agent with synergistic antibacterial effect by encapsulating iodide ions in silver cage and preparation method and application of antibacterial agent

Abstract

The invention discloses an antibacterial agent with iodide ions encapsulated in a silver cage and a synergistic antibacterial effect as well as a preparation method and application of the antibacterial agent, and relates to the technical field of antibacterial materials. The antibacterial agent takes a 16-core silver cage as a basic structural unit, iodide ions are packaged in the silver cage, and mercaptan is taken as a connector to assemble a one-dimensional chain structure. According to the antibacterial agent, iodide ions are packaged in a silver cage, and diversification of the performance and the structure of an antibacterial material can be achieved through the synergistic effect of multiple antibacterial mechanisms.

Description

Technical Field

[0001] The invention relates to the technical field of antibacterial materials, and in particular to an antibacterial agent with synergistic antibacterial effect and iodine ions encapsulated in a silver cage, and a preparation method and application thereof. Background Art

[0002] Persistent infections caused by multidrug-resistant bacteria and the spread of foodborne pathogens pose major challenges to human and animal health. The World Health Organization considers bacterial resistance to be one of the most pressing threats to global public health and development. Superbugs such as multidrug-resistant Gram-negative bacteria Klebsiella pneumoniae, Escherichia coli, Acinetobacter baumannii and Gram-positive bacteria methicillin-resistant Staphylococcus aureus cause hundreds of thousands of deaths each year. Therefore, there is an urgent need to explore new antimicrobial agents with good safety and strong antibacterial activity without the development of bacterial resistance to treat and prevent bacterial infections.

[0003] At present, various organic, inorganic and organic-inorganic hybrid antibacterial materials have been widely studied to improve their antibacterial properties. Among them, silver ions are widely known for their broad-spectrum bactericidal properties. They not only have a high efficiency in killing bacteria, fungi and viruses, but also have relatively low toxicity to mammalian cells and a low risk of introducing bacterial resistance. Therefore, metallic silver and its compounds have been widely used in various biomedical fields as antibacterial agents. The activity of these antibacterial agents is mainly attributed to several bactericidal mechanisms, including physical contact, release of silver ions, oxidative stress, and photothermal effects. In recent years, bacterial resistance and various mutant viruses have been continuously generated, and a single antibacterial mechanism is not enough to fully cope with complex bacterial infections. Therefore, it is particularly important to develop an efficient silver antibacterial system based on multiple antibacterial mechanisms. Summary of the invention

[0004] One of the objects of the present invention is to provide an antibacterial agent which encapsulates iodine ions in a silver cage and can act synergistically through multiple antibacterial mechanisms.

[0005] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: an antibacterial agent with synergistic antibacterial effect that encapsulates iodide ions in a silver cage, the antibacterial agent uses a 16-core silver cage as a basic structural unit, and encapsulates iodide ions in the silver cage, uses thiol as a connector, and assembles into a one-dimensional chain structure.

[0006] Wherein, the antibacterial agent can generate hydroxyl radicals under light conditions, and the hydroxyl radicals react with I - 、Ag + Synergistic effect to kill bacteria.

[0007] Wherein, the molecular formula of the antibacterial agent is [Ag 14 ( m -S t Bu) 12 I2]n .

[0008] Another object of the present invention is to provide a method for preparing the above-mentioned antibacterial agent, which comprises the following steps: Silver metal salt, iodine salt, organic ligand and sodium alcoholate are dissolved in a solvent and placed in a reaction container, reacted at 105-130° C. for 24-72 hours, and after cooling, light yellow crystals are obtained, which are the antibacterial agent.

[0009] Among them, after cooling, filtering, washing, purification, drying and other operations (these operations can be performed in sequence) can be performed to improve the purity of the product.

[0010] The molar ratio of the silver metal salt, iodine salt, organic ligand and sodium alcoholate is 1:(1-2):(1-2):(1-2).

[0011] Wherein, the silver metal salt is a nitrate (such as silver nitrate).

[0012] Wherein, the iodine salt is selected from at least one (for example, one) of sodium iodide, potassium iodide, and tetraethylammonium iodide.

[0013] Wherein, the organic ligand is tert-butyl mercaptan.

[0014] Wherein, the sodium alkoxide is selected from at least one (for example, one) of sodium methoxide and sodium ethoxide.

[0015] Wherein, the solvent is selected from at least one of acetone, ethanol and water.

[0016] Wherein, the cooling rate is 10°C / h.

[0017] In addition, the aforementioned antibacterial agents can be used in the preparation of drugs with enhanced antibacterial activity.

[0018] At the same time, the aforementioned antimicrobial agent can also be used to improve the synergistic antimicrobial efficiency against Escherichia coli. Specifically, the antimicrobial agent crystals are ground into fine powder, and the antimicrobial agent powder is added to a culture dish containing a culture medium (e.g., nutrient agar culture medium), shaken and poured into a plate, and the plate is solidified, and the Escherichia coli liquid is evenly coated, and cultured at a constant temperature under light conditions (e.g., cultured at a constant temperature of 37°C for 18 hours under light).

[0019] Among them, every 2 to 8 mg of antibacterial agent corresponds to 10 mL of culture medium and 100 μL of Escherichia coli liquid.

[0020] Wherein, the concentration of the antibacterial agent is 0-0.8 mg / mL (preferably 0.8 mg / mL).

[0021] Wherein, the illumination is white light LED illumination.

[0022] The present invention constructs Ag 16 Silver nanocages are used to encapsulate iodide ions in the silver cages, and then thiol is used as a connector to assemble an antibacterial agent with a one-dimensional chain structure. The antibacterial agent has simple synthesis steps, is cheap and easy to obtain, has suitable stability, and can continuously and stably release I - and Ag + , and produces hydroxyl radicals under light, which has good synergistic antibacterial activity. Moreover, the antibacterial agent can synergize through three antibacterial mechanisms to achieve the diversification of antibacterial material performance and structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A microscopic diagram of the antimicrobial agent encapsulating iodine ions in a silver cage; Figure 2 is an X-ray powder diffraction pattern of an antimicrobial agent encapsulating iodide ions in a silver cage; Figure 3 Thermogravimetric curve of the antimicrobial agent encapsulating iodine ions in silver cages; Figure 4 The antibacterial effect of the antibacterial agent encapsulating iodine ions in silver cages at different concentrations; Figure 5 Schematic diagram of the synergistic antibacterial effects of the three antibacterial mechanisms of the antibacterial agent encapsulating iodine ions in silver cages; Figure 6 The EPR image of the antimicrobial agent encapsulating iodide ions in a silver cage; Figure 7 This is a SEM image of the antimicrobial agent encapsulating iodine ions in silver cages killing Escherichia coli. DETAILED DESCRIPTION

[0024] In order to facilitate the understanding of those skilled in the art, the present invention is further described below in conjunction with the examples, and the contents mentioned in the examples are not limitations of the present invention. It should be noted in advance that the following examples were completed in the laboratory, and those skilled in the art should understand that the amounts of the components given in the examples only represent the ratio relationship between the components, rather than specific limitations.

[0025] The present invention aims to develop a highly effective antibacterial agent with multiple antibacterial mechanisms to address the problem of persistent infection caused by complex bacterial infections and multi-drug resistant bacteria. Among them, metallic silver and its compounds are widely used in various biomedical fields due to their versatility and effectiveness, and are one of the commonly used antibacterial agents. Iodine, as an efficient and inexpensive topical bactericide, can cause irreversible and nonspecific damage to microbial cells, help overcome the problem of drug resistance, and is also widely used in the antibacterial field. Studies have shown that adding iodine to antibacterial agents can significantly improve the overall antibacterial efficacy.

[0026] Based on the above concept, the present invention provides an antibacterial agent that encapsulates iodine ions in a silver cage and can act synergistically through multiple antibacterial mechanisms. The antibacterial agent uses a 16-nuclear silver cage as a basic structural unit, and encapsulates iodine ions in the silver cage, using thiol as a connector to assemble into a one-dimensional chain structure. The molecular formula of the antibacterial agent is [Ag 14 ( m -S t Bu) 12 I2] n .

[0027] Among them, the above antibacterial agent can generate hydroxyl radicals under light conditions, and the hydroxyl radicals react with I - 、Ag + Synergistic effect to kill bacteria.

[0028] The above antibacterial agent can be prepared by the following preparation method, the steps are as follows: (1) Dissolve silver metal salt, iodine salt, organic ligand and sodium alcoholate in a solvent for later use; (2) transferring the mixed solution of step (1) into a reaction vessel (e.g., a reactor), reacting at a temperature of 105 to 130° C. (e.g., 105° C., 120° C., or 130° C.) for 24 to 72 hours (e.g., 24 hours, 33 hours, or 72 hours), and cooling (e.g., programmed cooling) to room temperature; (3) Filtration and washing; (4) Purify and dry to obtain light yellow crystals, which are antibacterial crystal materials.

[0029] Furthermore, the above preparation method comprises the following steps: First, add sodium alcoholate and organic ligand to solvent A and stir (30 minutes) to fully dissolve them. Next, dissolve the silver metal salt in solvent B and then add it dropwise to the previous solution. At this point, the mixture will turn milky white and begin to form flocculent precipitates. After that, add iodine salt and solvent C to the reaction system in sequence. Transfer the resulting turbid mixture to a high-pressure reactor, react at a temperature of 105-130°C for 24-72 hours, program cooling to room temperature, and after the reactor is cooled, filter, wash, purify (remove white impurities), and dry to obtain a light yellow crystalline antibacterial agent.

[0030] In step (1), the molar ratio of silver metal salt, iodine salt, organic ligand and sodium alkoxide is 1:(1-2):(1-2):(1-2). For example, the molar ratio is 1:1:1:1 or 1:1.5:1.5:1.5 or 1:2:2:2.

[0031] In step (1), the silver metal salt is a nitrate (such as silver nitrate), the iodide salt is selected from at least one (for example, one) of sodium iodide, potassium iodide, and tetraethylammonium iodide, the organic ligand is tert-butyl mercaptan, and the sodium alkoxide is selected from at least one (for example, one) of sodium methoxide and sodium ethoxide.

[0032] In step (1), the solvent is selected from at least one of acetone, ethanol and water. The solvent includes solvents used in three stages, the solvent A in the first stage is ethanol, the solvent B in the second stage is a mixed solution of water and ethanol, and the solvent C in the third stage includes acetone and ethanol. The solvents used in the three stages, namely solvent A, solvent B, and solvent C, are used in a ratio (volume ratio) of 2:1:1. In the second stage, the ratio (volume ratio) of water to ethanol is 1:2. In the third stage, the ratio (volume ratio) of acetone to ethanol is 2:1.

[0033] In step (2), the cooling rate is 10°C / h.

[0034] The present invention is achieved by combining I with excellent antibacterial properties - and Ag + , self-assembled with organic ligands to obtain a molecular formula of [Ag 14 ( m -S t Bu) 12 I2] n An antibacterial agent comprising I - and Ag + , can achieve joint antibacterial, and can also achieve the diversification of antibacterial material performance and structure. Moreover, the antibacterial agent constructs a Ag-based 16 The one-dimensional chain structure of the silver nanocage encapsulates iodide ions in the silver cage, which has suitable stability and can continuously and stably release I - and Ag + , and produces hydroxyl radicals under light, with good synergistic antibacterial activity. At the same time, the antibacterial agent has a good synergistic antibacterial effect on Escherichia coli, its preparation process is simple, the raw materials have good biocompatibility, and it is cheap and easy to obtain, easy to transform into clinical direction, and has good application prospects.

[0035] The present invention is further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto. Example 1

[0036] In this example, antimicrobial crystals encapsulating iodide ions in silver cages were prepared according to the following method.

[0037] First, 0.014 g (0.2 mmol) of sodium ethoxide and 0.022 mL (0.2 mmol) of tert-butyl mercaptan were added to 6 mL of ethanol and stirred for 30 minutes to fully dissolve. Next, 0.034 g (0.2 mmol) of silver nitrate was dissolved in a mixed solution of 1 mL of water and 2 mL of ethanol, and then slowly added to the previous solution. At this time, the mixture will turn milky white and begin to form flocculent precipitates. After that, 0.029 g (0.2 mmol) of sodium iodide, 2 mL of acetone, and 1 mL of ethanol were added to the reaction system in sequence. The obtained turbid mixture was transferred to a high-pressure reactor and heated at 105 ° C for 24 hours. The temperature was programmed to cool (10 ° C / min) to room temperature. After the reactor was cooled, it was filtered, washed with DMF, water, and ethanol three times to remove white impurities, and dried to obtain a light yellow crystalline antibacterial agent. Example 2

[0038] In this example, antimicrobial crystals encapsulating iodide ions in silver cages were prepared according to the following method.

[0039] First, 0.017 g (0.3 mmol) of sodium methoxide and 0.033 mL (0.3 mmol) of tert-butyl mercaptan were added to 6 mL of ethanol and stirred for 30 minutes to fully dissolve. Next, 0.034 g (0.2 mmol) of silver nitrate was dissolved in a mixed solution of 1 mL of water and 2 mL of ethanol, and then slowly added to the previous solution. At this time, the mixture will turn milky white and begin to form flocculent precipitates. After that, 0.771 g (0.3 mmol) of tetraethylammonium iodide, 2 mL of acetone, and 1 mL of ethanol were added to the reaction system in sequence. The obtained turbid mixture was transferred to a high-pressure reactor and heated at 120 ° C for 72 hours. The temperature was programmed to cool (10 ° C / min) to room temperature. After the reactor was cooled, it was filtered, washed with DMF, water, and ethanol three times to remove white impurities, and dried to obtain a light yellow crystalline antibacterial agent. Example 3

[0040] In this example, antimicrobial crystals encapsulating iodide ions in silver cages were prepared according to the following method.

[0041] First, 0.028 g (0.4 mmol) of sodium ethoxide and 0.043 mL (0.4 mmol) of tert-butyl mercaptan were added to 6 mL of ethanol and stirred for 30 minutes to fully dissolve. Next, 0.034 g (0.2 mmol) of silver nitrate was dissolved in a mixed solution of 1 mL of water and 2 mL of ethanol, and then slowly added to the previous solution. At this time, the mixture will turn milky white and begin to form flocculent precipitates. After that, 0.066 g (0.4 mmol) of potassium iodide, 2 mL of acetone, and 1 mL of ethanol were added to the reaction system in sequence. The obtained turbid mixture was transferred to a high-pressure reactor and heated at 130 ° C for 33 hours. The temperature was programmed to cool (10 ° C / min) to room temperature. After the reactor was cooled, it was filtered, washed with DMF, water, and ethanol three times to remove white impurities, and dried to obtain a light yellow crystalline antibacterial agent.

[0042] The antibacterial crystals prepared in Example 1 and encapsulating iodine ions in silver cages were used for data collection using a single crystal X-ray diffractometer and structural analysis was performed using Olex2 software. Figure 1 As shown, the antibacterial agent is composed of 16-nuclear silver cage basic units encapsulating iodide ions, which are self-assembled into a stable one-dimensional chain structure through tert-butylthiol linkers. Figure 2 As shown in Figure 2, the simulated peaks of XRD are consistent with the test peaks, indicating that the obtained antibacterial agent is a pure phase and can be used for structural characterization and antibacterial performance testing. Figure 3 As shown, the antibacterial agent crystal material has good thermal stability and can exist stably before 285°C.

[0043] The subsequent antibacterial properties of the antibacterial materials prepared in Examples 1-3 are basically the same. Antibacterial test

[0044] The antibacterial agent crystals prepared in Example 1 were selected to carry out the following experiment.

[0045] The strain selected for this experiment is Escherichia coli MG1655. First, grind the antimicrobial crystals into very fine powder, add 10 mL of nutrient agar medium to each culture dish, then add 2 mg, 4 mg, 6 mg, 7 mg, and 8 mg of antimicrobial powder respectively, shake well, pour the plate, and evenly apply 10 6 The Escherichia coli solution (100 μL) was cultured at 37°C for 18 h under light conditions and compared with a blank plate without antimicrobial agents. The growth of Escherichia coli colonies was observed and photographed. The antibacterial effect of the antimicrobial agents at different concentrations was investigated by colony counting.

[0046] Result analysis: Figure 4As shown, with the increase of the powder concentration of the antibacterial agent prepared in Example 1, it can be clearly seen that the colony count is significantly reduced, and the inhibitory effect on the growth of Escherichia coli is gradually enhanced. When the antibacterial agent concentration is 0.8 mg / mL, the bacteria can be completely killed. In the antibacterial experiment determination, the relevant data analysis of the antibacterial performance of Escherichia coli was selected, but in fact, it was concluded in other tests that the antibacterial agent also has strong antibacterial performance against multiple strains such as Streptococcus mutans, Actinomyces viscous, and Lactobacillus paracasei.

[0047] like Figure 5 As shown in the schematic diagram of the antibacterial mechanism, the antibacterial agent kills bacteria through the synergistic action of three antibacterial mechanisms. The antibacterial agent can continuously and stably release silver ions and iodine ions, and produce hydroxyl free radicals (such as Figure 6 As shown in Figure 2), the three work synergistically to kill bacteria. Figure 7 As can be seen from the SEM image of E. coli shown, the cells of E. coli are completely destroyed.

[0048] Since the above antibacterial agent has strong antibacterial properties against Escherichia coli, Streptococcus mutans, Actinomyces viscosus, Lactobacillus paracasei and other bacterial species, the antibacterial agent can be used in the preparation of drugs with enhanced antibacterial activity and has good application prospects.

[0049] The above embodiments are preferred implementation schemes of the present invention. In addition, the present invention may also be implemented in other ways. Any obvious replacement without departing from the concept of the present technical solution is within the protection scope of the present invention.

[0050] Finally, it should be emphasized that in order to allow ordinary technicians in the field to more easily understand the improvements of the present invention over the prior art, some descriptions of the present invention have been simplified, and for the sake of clarity, some other elements are omitted in this application document. Those skilled in the art should realize that these omitted elements may also constitute the content of the present invention.

Claims

1. An antibacterial agent having a synergistic antibacterial effect by encapsulating iodine ions in a silver cage, characterized in that: The antibacterial agent uses a 16-nuclear silver cage as a basic structural unit, encapsulates iodide ions in the silver cage, and uses thiol as a connector to assemble into a one-dimensional chain structure.

2. The antibacterial agent according to claim 1, characterized in that: The antibacterial agent can generate hydroxyl radicals under light conditions, and the hydroxyl radicals react with I - 、Ag + Synergistic effect to kill bacteria.

3. The method for preparing the antibacterial agent according to claim 1 or 2, characterized in that: The following steps are involved: Silver metal salt, iodine salt, organic ligand and sodium alcoholate are dissolved in a solvent and placed in a reaction container, reacted at 105-130° C. for 24-72 hours, and after cooling, light yellow crystals are obtained, which are the antibacterial agent.

4. The method for preparing the antibacterial agent according to claim 3, characterized in that: The molar ratio of the silver metal salt, iodine salt, organic ligand and sodium alcoholate is 1:(1-2):(1-2):(1-2).

5. The method for preparing the antibacterial agent according to claim 3, characterized in that: The silver metal salt is nitrate, the iodine salt is selected from at least one of sodium iodide, potassium iodide, and tetraethylammonium iodide, the organic ligand is tert-butyl mercaptan, the sodium alcoholate is selected from at least one of sodium methoxide and sodium ethoxide, and the solvent is selected from at least one of acetone, ethanol, and water.

6. Use of the antibacterial agent according to claim 1 or 2 in the preparation of drugs with enhanced antibacterial activity.

7. Use of the antibacterial agent according to claim 1 or 2 in improving the synergistic antibacterial efficiency against Escherichia coli.

8. The use of the antibacterial agent according to claim 7 in improving the synergistic antibacterial efficiency against Escherichia coli, characterized in that: The antimicrobial agent crystals are ground into fine powder, added to a culture dish containing a culture medium, shaken and poured onto a plate, and after the plate solidifies, the Escherichia coli liquid is evenly coated and cultured at a constant temperature under light conditions.

9. The use of the antibacterial agent according to claim 8 in improving the synergistic antibacterial efficiency against Escherichia coli, characterized in that: Every 2-8 mg of antimicrobial agent corresponds to 10 mL of culture medium and 100 μL of E. coli solution.

10. The use of the antibacterial agent according to claim 8 in improving the synergistic antibacterial efficiency against Escherichia coli, characterized in that: The concentration of the antibacterial agent is 0-0.8 mg / mL.

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