An antibacterial agent, its preparation method and use

Abstract

This invention relates to the field of antibacterial materials technology, specifically to an antibacterial agent, its preparation method, and its application. The preparation method of the antibacterial agent includes the following steps: (1) Ga microsphere preparation: obtaining a liquid gallium metal microsphere suspension; (2) Ag deposition to form a core-shell structure Ga@Ag antibacterial agent. This invention achieves complete Ag encapsulation for the first time through spontaneous reduction and complexation regulation, significantly improving the utilization rate of effective silver; the dual action mechanism of Ga and Ag can also effectively inhibit the growth of drug-resistant bacteria, and has advantages such as high antibacterial efficiency, strong stability, good dispersibility, and low cost, and is suitable for various application scenarios such as antibacterial coatings, polymer materials, and medical protective materials.

Description

Technical Field

[0001] This invention relates to the field of antibacterial materials technology, specifically to an antibacterial agent, its preparation method, and its application. Background Technology

[0002] Silver (Ag) has long been widely used in medical devices, public health materials, textile modification, and functional coatings due to its excellent broad-spectrum antibacterial properties. However, with the continuous increase in demand for traditional silver-based antibacterial materials, the price of silver raw materials has risen significantly in recent years, leading to a continuous increase in the cost of silver nanoparticle antibacterial agents, which restricts their widespread use in large-scale industrial systems. Furthermore, Ag nanoparticles exhibit a significant aggregation tendency during use, easily agglomerating into large particles in the system, resulting in a decrease in specific surface area and a reduced silver ion release rate, ultimately causing the antibacterial efficiency to fall below the theoretical value. Simultaneously, Ag nanoparticles are prone to oxidation and sulfidation in air and solution environments, further affecting their stability and antibacterial lifespan.

[0003] Currently, in order to solve the problems of high cost, easy agglomeration, and poor stability of Ag antibacterial agents, the academic and industrial communities have begun to try to use other metals as carriers and structural templates. Recent studies have shown that Ga has certain antibacterial effects. However, in the existing antibacterial material system, although Ag or Ga alone has certain effects, common antibacterial agents still generally have the following shortcomings: (1) Poor material dispersibility: Traditional metal nanopowders are easy to agglomerate in polymer or water systems; (2) Short antibacterial lifespan: The release rate of metal ions is uncontrollable, and there is often a problem of "excessive release in the early stage - insufficient release in the later stage"; (3) High cost and non-scalability: Especially silver-based materials, which put economic pressure on large-scale industrial applications; (4) Poor interfacial bonding: The compatibility between metal powder and matrix (coating, resin, fiber) is insufficient, which leads to easy migration or detachment of antibacterial agents; (5) Uncontrollable structure: Core-shell structure or alloy structure is difficult to prepare stably and uniformly, which affects the stability of material performance.

[0004] To reduce costs and improve stability and antibacterial properties, some studies have attempted to deposit Ag on the surface of Ga microspheres to construct Ga@Ag structures. However, in existing literature and publicly available technologies, Ag is often deposited discontinuously on the Ga surface in island-like or patchy forms, resulting in insufficient Ag coverage and uneven distribution, leading to low surface area utilization and significant fluctuations in antibacterial performance. Furthermore, a large amount of Ag in the island-like structures is partially embedded in the recessed areas of the Ga surface, failing to fully participate in the antibacterial action and further reducing the effectiveness of each unit of silver dosage. In view of these problems, this invention provides an antibacterial agent, its preparation method, and its application. Summary of the Invention

[0005] The technical problem to be solved by this invention is to provide an antibacterial agent, its preparation method, and its application. The aim is to construct a Ga@Ag core-shell structured antibacterial agent with low silver content, lower cost, uniform structure, multiple antibacterial mechanisms, stable performance, and scalable preparation.

[0006] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: In a first aspect, a method for preparing an antibacterial agent includes the following steps: (1) Preparation of Ga microspheres: Add metallic gallium to a mixed solvent of ethanol and deionized water, then add polyvinylpyrrolidone (PVP), and sonicate to form gallium microspheres to obtain a liquid metallic gallium microsphere suspension; (2) Ag deposition to form an antibacterial agent: A silver ammonia complex solution and ascorbic acid were added to the liquid gallium microsphere suspension. Under the condition of maintaining ultrasound and stirring, the silver ammonia complex solution was deposited with [Ag(NH3)2]. + (Diammine silver complex ions) spontaneously reduce and uniformly deposit on the surface of the gallium microspheres to form composite particles with Ga as the core and Ag as the shell, which are antibacterial agents.

[0007] Based on the above technical solution, the present invention can be further improved as follows.

[0008] Furthermore, the Ga microspheres mentioned in step (1) have a particle size of 100 nm to 2 μm.

[0009] Furthermore, in step (1), the volume ratio of ethanol to deionized water in the mixed solvent is 1:1 to 1:5; The solid-liquid ratio of polyvinylpyrrolidone to the mixed solvent in step (1) is (0.1~2) g: 100 mL; The mass concentration of gallium in the liquid gallium microsphere suspension in step (1) is 0.2 g / mL to 1.0 g / mL.

[0010] Furthermore, the silver ammonia complex solution described in step (2) is prepared by the following steps: adding ammonia water to silver nitrate solution to generate silver ammonia complex solution.

[0011] Furthermore, the silver nitrate solution contains Ag + The concentration ranges from 1 mM to 50 mM; The silver ammonia complex solution contains [Ag(NH3)2] + The concentration ranges from 1 mM to 50 mM.

[0012] Furthermore, the ascorbic acid and the silver ammonia complex solution contain [Ag(NH3)2]. + The molar ratio is 1.2~5:1.

[0013] Furthermore, while maintaining ultrasound and stirring, the [Ag(NH3)2] in the silver ammonia complex solution was further [dissolved]. + The conditions for reduction and uniform deposition on the surface of the gallium microspheres are as follows: temperature 20~40℃, time 0.5~3h, ultrasonic power 100 W~500W, and stirring speed 200 rpm~800 rpm.

[0014] Secondly, an antibacterial agent, said antibacterial agent being prepared by the preparation method described above.

[0015] Furthermore, in the composite particles of the antibacterial agent, Ga accounts for 20% to 80% of the mass of the composite particles, and the Ag shell thickness is 5 nm to 80 nm.

[0016] Thirdly, the application of an antimicrobial agent, wherein the antimicrobial agent is used in the antimicrobial modification of coatings, adhesives, plastics, fibers and medical devices.

[0017] This invention utilizes metallic gallium (Ga) and silver ions (Ag) ＋ Significant electrode potential difference (Ga) between 3＋ / Ga: –0.53V; Ag ＋ / Ag: +0.80 V), making Ag ＋ Without the need for an external current, it can be spontaneously reduced by liquid Ga metal. With the aid of PVP coordination protection, silver ammonia complex ion regulation of the reduction rate, and ultrasonic surface renewal, uniform nucleation and dense growth are achieved on the surface of its microspheres, constructing continuous and stable Ga@Ag core-shell composite particles. The Ag shell provides the main antibacterial activity, while the Ga core plays a crucial role in electron supply, nucleation template, and synergistic antibacterial action. The Ag shell achieves rapid antibacterial activity by disrupting bacterial membrane structure and inhibiting the bacterial respiratory chain; the Ga core interferes with bacterial iron metabolism (Ga@Ag core-shell structure) through a "pseudo-iron effect." 3＋ Can simulate Fe 3＋ While Ga enters the bacterial metabolic system, it cannot perform the biological functions of iron ions, leading to the inhibition of bacterial energy metabolism and DNA synthesis, thus achieving the "pseudo-iron effect" of bacterial inhibition. This inhibits DNA synthesis and enzyme activity from within the cell. At the same time, Ga's liquid properties make Ag nucleation more uniform, avoiding the problems of easy aggregation and inactivation of traditional Ag nanoparticles, thereby significantly improving the stability of the material. In addition, unlike the island-like and discontinuous deposition of silver on the Ga surface in existing literature, this invention achieves complete Ag encapsulation for the first time through spontaneous reduction and complexation regulation, greatly improving the utilization rate of effective silver. The dual action mechanism of Ga and Ag can also effectively inhibit the growth of drug-resistant bacteria.

[0018] In summary, the Ga@Ag core-shell structured antibacterial material of the present invention has advantages such as high antibacterial efficiency, strong stability, good dispersibility and low cost, and is suitable for various application scenarios such as antibacterial coatings, polymer materials and medical protective materials.

[0019] The beneficial effects of this invention are: (1) This invention achieves complete and continuous coating of Ag on Ga surface for the first time, significantly improving antibacterial efficiency: This invention utilizes the liquid metal properties of Ga as a nucleation template, enabling Ag to form a complete and continuous coating on Ga surface, significantly improving antibacterial efficiency. ＋ It can uniformly deposit on its surface, forming a dense, continuous core-shell structure. Unlike traditional Ag / Ga composite systems where Ag is deposited in island-like, sheet-like, or incomplete forms, this invention achieves a complete Ag shell for the first time, increasing the exposed area and effective utilization rate of silver, thereby significantly enhancing antibacterial properties. The dense and stable Ag shell is not easily detached, enabling the material to exhibit good stability and high dispersibility in various liquid, plastic, coating, and fiber systems.

[0020] (2) This invention reduces material costs while maintaining strong antibacterial ability and stability: By using metallic Ga as a supporting core, the amount of precious metal Ag used can be significantly reduced, so that the material can maintain excellent antibacterial ability while reducing costs, making it suitable for large-scale production. The liquid properties of the Ga core endow the material with excellent interfacial wettability and adhesion, so that the Ga@Ag particle antibacterial agent is evenly dispersed in matrix materials such as coatings, resins, and rubbers, and is difficult to agglomerate. Its stability is significantly better than that of traditional Ag nanoparticles.

[0021] (3) The synergistic antibacterial effect of the present invention is significantly enhanced, and it is particularly suitable for the inhibition of drug-resistant bacteria: Ag exerts a rapid antibacterial effect by destroying the bacterial membrane structure, while Ga inhibits bacterial metabolism through the "pseudo-iron effect". The two mechanisms complement each other and can effectively inhibit common pathogens such as Pseudomonas aeruginosa and Staphylococcus aureus. This dual-mechanism antibacterial mode can significantly improve the broad-spectrum antibacterial performance and long-term antibacterial life of the material.

[0022] (4) The process of this invention is simple, the conditions are mild, and it is easy to scale up industrially: The preparation process of this invention does not require high temperature, high pressure or electrochemical equipment. The reduction of Ag is spontaneously completed by Ga. The system formula is simple, the reaction is mild, and the operation is easy to control. Compared with the complex process of existing antibacterial additives, this invention has higher operability and industrial adaptability. It can be directly used in the production lines of coatings, plastics, rubber and medical materials, so as to achieve rapid promotion and application. Detailed Implementation

[0023] The principles and features of this invention are described below. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they should be performed according to the techniques or conditions described in the literature in this field, or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased through legitimate channels.

[0024] Example 1 A method for preparing an antibacterial agent based on a Ga@Ag core-shell structure includes the following steps: (1) Preparation of liquid gallium microsphere suspension: metallic gallium (Ga) was added to a mixed solvent of ethanol / deionized water, wherein the volume ratio of ethanol to deionized water in the mixed solvent was 1:1; polyvinylpyrrolidone (PVP) was then added, and the mixture was treated in an ultrasonic device for 2 h. After gradient centrifugation, a liquid metallic gallium microsphere suspension was obtained; the average particle size of the gallium microspheres was measured to be approximately 300~800 nm; the concentration of Ga in the suspension was 0.5 g / mL, and the solid-liquid ratio (g:mL) of PVP to the mixed solvent was 0.2:100.

[0025] (2) Preparation of silver ammonia complex ion solution: Add ammonia water dropwise to a 20 mM silver nitrate solution until the precipitate is completely dissolved to obtain a transparent silver ammonia complex ion solution [Ag(NH3)2]. ＋ The silver ammonia complex ion can stabilize Ag. ＋ To avoid uneven deposition caused by excessively rapid reduction; (3) Preparation of ascorbic acid reducing agent solution: Dissolve ascorbic acid in deionized water to obtain an ascorbic acid solution with a concentration of 20 mM for later use; (4) Antibacterial agent for constructing Ga@Ag core-shell structure: The gallium microsphere suspension obtained in step (1) was placed under the combined action of ultrasound and mechanical stirring. At room temperature (about 25°C), the silver ammonia complex ion solution from step (2) and the ascorbic acid solution from step (3) were added to the gallium suspension at an equal rate. As the addition proceeded, the solution gradually turned light gray, indicating that the Ag ＋ Gallium metal was spontaneously reduced and deposited on its surface. After reacting for another 1 h, the product was collected by centrifugation, washed successively with ethanol and deionized water, and finally dried under vacuum at 40 °C for 8 h to obtain uniform Ga@Ag core-shell structured antibacterial particles.

[0026] Test case (1) Antibacterial performance test: The antibacterial agent of Ga@Ag core-shell structured particles prepared according to the method of the present invention was added to the water-based coating at a mass fraction of 0.2 wt%. After being fully dispersed, it was uniformly coated on the surface of the glass substrate and dried at 60°C to constant weight.

[0027] Subsequently, inhibition zone tests were conducted against *Pseudomonas aeruginosa* and *Staphylococcus aureus* according to the standard method of GB / T 21866-2023 to evaluate the antibacterial properties of the material. For *Pseudomonas aeruginosa*, the inhibition zone diameter of Ag nanoparticles (Ag NPs) was 2–4 mm, and that of Ga nanoparticles (Ga NPs) was 2 mm. However, the inhibition zone diameter of the Ga@Ag core-shell structured antibacterial particles obtained in this invention was significantly increased to 5–7 mm. For *Staphylococcus aureus*, the inhibition zone diameter of Ag NPs was 2 mm, that of Ga NPs was 1 mm, while the inhibition zone diameter of the Ga@Ag core-shell structured antibacterial particles reached 7–8 mm.

[0028] The results clearly show that the inhibition zone diameter of the Ga@Ag core-shell structured antibacterial particles prepared in this invention is much larger than that of the control group Ag NPs and Ga NPs in both typical strains; the antibacterial activity of the Ga@Ag core-shell structure material is significantly improved, exhibiting a clear synergistic effect; the inhibition zone diameter of Ga@Ag is about 2 to 4 times larger than that of Ag NPs and about 5 to 8 times larger than that of Ga NPs, indicating that the effective antibacterial effect of Ga@Ag material is greatly enhanced; the significantly expanded inhibition zone range indicates that the continuous coating structure of the Ag shell on the Ga core surface prepared in this invention can effectively increase the available antibacterial active sites, thereby significantly enhancing the antibacterial ability.

[0029] In summary, (1) this invention achieves complete and continuous coating of Ag on the Ga surface for the first time, significantly improving antibacterial efficiency: this invention utilizes the liquid metal properties of Ga as a nucleation template, enabling Ag to... ＋It can be uniformly deposited on its surface to form a dense and continuous core-shell structure. Unlike the traditional Ag / Ga composite system where Ag is deposited in island, sheet or incomplete form, this invention achieves a complete Ag shell for the first time, increasing the exposed area and effective utilization rate of silver, thereby significantly enhancing antibacterial performance. The Ag shell is dense and stable and not easy to fall off, so that the material exhibits good stability and high dispersibility in various liquid, plastic, coating and fiber systems. (2) This invention reduces material cost while maintaining strong antibacterial ability and stability: by using metallic Ga as a supporting core, the amount of precious metal Ag used can be significantly reduced, so that the material can maintain excellent antibacterial ability while reducing cost, making it suitable for large-scale production. The liquid properties of the Ga core give the material excellent interfacial wettability and adhesion, so that Ga@Ag particle antibacterial agent is uniformly dispersed in matrix materials such as coatings, resins, and rubbers, and is difficult to agglomerate, with significantly better stability than traditional Ag nanoparticles. (3) The synergistic antibacterial effect of this invention is significantly enhanced, especially suitable for inhibiting drug-resistant bacteria: Ag exerts a rapid antibacterial effect by disrupting the bacterial membrane structure, while Ga inhibits bacterial metabolism through the "pseudo-iron effect." The two mechanisms complement each other and can effectively inhibit common pathogens such as Pseudomonas aeruginosa and Staphylococcus aureus. This dual-mechanism antibacterial mode can significantly improve the broad-spectrum antibacterial performance and long-term antibacterial lifespan of the material. (4) The process of this invention is simple, the conditions are mild, and it is easy to scale up industrially: The preparation process of this invention does not require high temperature, high pressure, or electrochemical equipment. The reduction of Ag is spontaneously completed by Ga. The system formulation is simple, the reaction is mild, and the operation is easy to control. Compared with the complex processes of existing antibacterial additives, this invention has higher operability and industrial adaptability. It can be directly used in the production lines of coatings, plastics, rubber, and medical materials to achieve rapid promotion and application.

[0030] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing an antibacterial agent, characterized in that, Includes the following steps: (1) Preparation of Ga microspheres: Add metallic gallium to a mixed solvent of ethanol and deionized water, then add polyvinylpyrrolidone, and sonicate to form gallium microspheres to obtain a liquid metallic gallium microsphere suspension; (2) Ag deposition to form an antibacterial agent: A silver ammonia complex solution and ascorbic acid are added dropwise to the liquid gallium microsphere suspension. Under the condition of maintaining ultrasound and stirring, the silver ammonia complex solution contains [Ag(NH3)2]. + The Ga microspheres are reduced and uniformly deposited on their surface to form composite particles with Ga as the core and Ag as the shell, which are the antibacterial agents.

2. The method for preparing an antibacterial agent according to claim 1, characterized in that, The Ga microspheres mentioned in step (1) have a particle size of 100 nm to 2 μm.

3. The method for preparing an antibacterial agent according to claim 1, characterized in that, In step (1), the volume ratio of ethanol to deionized water in the mixed solvent is 1:1 to 1:5; The solid-liquid ratio of polyvinylpyrrolidone to the mixed solvent in step (1) is (0.1~2) g: 100 mL; The mass concentration of gallium in the liquid gallium microsphere suspension in step (1) is 0.2 g / mL to 1.0 g / mL.

4. The method for preparing an antibacterial agent according to claim 1, characterized in that, The silver ammonia complex solution described in step (2) is prepared by the following steps: adding ammonia water to silver nitrate solution to generate silver ammonia complex solution.

5. The method for preparing an antibacterial agent according to claim 4, characterized in that, Ag in silver nitrate solution + The concentration ranges from 1 mM to 50 mM; The silver ammonia complex solution contains [Ag(NH3)2] + The concentration ranges from 1 mM to 50 mM.

6. A method for preparing an antibacterial agent according to any one of claims 1 to 5, characterized in that, The ascorbic acid and the silver ammonia complex solution contain [Ag(NH3)2]. + The molar ratio is 1.2~5:

1.

7. A method for preparing an antibacterial agent according to any one of claims 1 to 5, characterized in that, While maintaining ultrasound and stirring, [Ag(NH3)2] in the silver ammonia complex solution was... + The conditions for reduction and uniform deposition on the surface of the gallium microspheres are as follows: temperature 20~40℃, time 0.5~3h, ultrasonic power 100 W~500 W, and stirring speed 200 rpm~800 rpm.

8. An antibacterial agent, characterized in that, The antibacterial agent is prepared by the preparation method according to any one of claims 1 to 7.

9. The antibacterial agent according to claim 8, characterized in that, In the composite particles of the antibacterial agent, Ga accounts for 20% to 80% of the mass of the composite particles, and the Ag shell thickness is 5 nm to 80 nm.

10. The application of an antibacterial agent, characterized in that, The antimicrobial agent according to any one of claims 8 to 9 is used in the antimicrobial modification of coatings, adhesives, plastics, fibers and medical devices.