An indole acetic acid ester monomer and a polymer antibacterial material containing the monomer unit

Abstract

The present application relates to a kind of indole acetic acid ester monomer and the polymer antibacterial material containing the monomer unit, wherein indole acetic acid ester monomer has the following structure: Polymer antibacterial material has the following structure: The present application is with the biomass indole acetic acid of excellent biocompatibility as functional component, by Steglich esterification reaction, indole acetic acid ester monomer is synthesized;Again using RAFT polymerization technology successfully prepared polymer antibacterial material with excellent antibacterial activity, and the antibacterial material can be applied to antibacterial coating, agricultural antibacterial and the like.

Description

Technical Field

[0001] This invention relates to the fields of materials science and antibacterial technology, and in particular to an indoleacetic acid monomer and a polymeric antibacterial material containing the monomer unit. Background Technology

[0002] The widespread growth and spread of microorganisms has led to various pollution problems, which have become a significant constraint on the development of multiple fields such as materials protection and agricultural production. This not only causes substantial material waste and a significant reduction in production efficiency but may also trigger a chain of environmental problems. Therefore, the development of efficient, environmentally friendly, and adaptable antimicrobial materials has become a key research focus and urgent need in the fields of materials science and agricultural applications. Currently, naturally biodegradable materials are attracting increasing attention from researchers as an effective strategy to replace traditional petrochemical products (W. Wang, et al. Biodegradable cellulose / curcumin films with Janus structure for foodpackaging and freshnessmonitoring. Carbohydrate Polymers, 2024, 324: 121516.). Among various antimicrobial materials, natural antimicrobial elements possess unique advantages such as excellent biocompatibility, biodegradability, and low likelihood of inducing drug resistance in pathogenic microorganisms. Compared with traditional chemical bactericides and some inorganic antimicrobial agents, they are more in line with the current application needs of green and sustainable development, and have become the core research and development direction of new antimicrobial materials (S. Jin, et al. Versatile synthesis of cellulose film with excellent electroothermal / photothermal dual responsiveness by introducing MXene and small molecule self-assembled nanosphere. Carbohydrate Polymers, 2024, 343: 122441.).

[0003] Indole, also known as benzopyrrole, is a class of easily synthesized, low-toxicity nitrogen-containing heterocyclic compounds (A. Kumari, et al. Medicinal chemistry of indole derivatives: Current to future therapeutic prospects. Bioorganic Chemistry, 2019, 89: e103021.). It not only possesses excellent biological activity but also serves as a novel fluorescent dye, finding wide application in the biomedical field. Indole derivatives are widely found in various natural products and exhibit broad biological activities, including antibacterial, anticonvulsant, antifungal, anti-inflammatory, antimalarial, antituberculosis, antiviral, and antitumor effects. It has been proven to be a very important active scaffold (Y. Khetmalis, et al. Oxindole and its derivatives: Areview on recent progress in biological activities. Biomedicine & Pharmacotherapy, 2021, 141: el11842.). Indole-3-acetic acid, a naturally occurring indole-based active compound, possesses a unique antibacterial action site within its intramolecular indole ring. By interfering with microbial cell metabolism and membrane structure integrity, it effectively inhibits the proliferation of various common harmful microorganisms. Furthermore, it is biodegradable, environmentally friendly, and has no adverse effects on crop growth, making it a highly promising antibacterial building block. Invention patent CN 120732846 A provides the use of indoleacetic acid or a pharmaceutically acceptable salt thereof in the preparation of products for the prevention and / or treatment of hypertension. Effective doses of indoleacetic acid or its pharmaceutically acceptable salt can be effectively used to prevent or treat hypertension, opening up new avenues for hypertension treatment.Studies have reported that three types of feed containing indoleacetic acid (IAA), gibberellic acid (GA), and coumaric acid (CUM) are non-toxic to bee larvae and adult bees, avoiding problems such as antibiotic resistance and bee product contamination caused by synthetic antibiotics (N. Szawarski, et al. Short communication: Antimicrobial activity of indoleacetic, gibberellic and coumaric acids against Paenibacillus larvae and its toxicity against Apismellifera. Spanish Journal of Agricultural Research, 2020, 18 (1): e05SC01.). Invention patent CN121517347A discloses a class of indoleamide derivatives, their preparation methods, and uses. Using indole as the parent skeleton, amide bonds are introduced for structural diversity optimization and modification, and further functional groups such as methoxyamine are introduced. This series of compounds exhibits good antibacterial activity; among them, several compounds show good control effects against various important crop diseases. Furthermore, studies have found that spermine derivatives of indole-3-carboxylic acid, indole-3-acetic acid, and indole-3-acrylic acid can synergistically enhance the inhibitory effects of doxycycline on *Pseudomonas aeruginosa*, *Escherichia coli*, and *Klebsiella pneumoniae*, and exhibit good biocompatibility (M. Cadelis, et al. Spermine Derivatives of Indole-3-carboxylic Acid, Indole-3-acetic Acid and Indole-3-acrylic Acid as Gram-Negative Antibiotic Adjuvants. ChemMedChem, 2021, 16: 513-523). However, the long-lasting antibacterial effect of these small molecule derivative monomers is difficult to maintain, limiting their practical application. Invention patent CN119970724A discloses the application of 3-indoleacetic acid combined with temozolomide in the treatment of glioma. Specifically, 3-indoleacetic acid significantly enhances the inhibitory effect of temozolomide on glioma cells in both short and long-term effects, and also significantly enhances the apoptosis-inducing effect of temozolomide on glioma cells. When 3-indoleacetic acid combined with temozolomide is used in an animal model of glioma, it significantly inhibits glioma development and reduces weight loss induced by temozolomide administration. Therefore, 3-indoleacetic acid combined with temozolomide has the potential to develop anti-glioma drugs.Invention patent CN 103098586A discloses the application of indoleacetic acid in the enhanced remediation of polycyclic aromatic hydrocarbon (PAH) contaminated soil. This invention features a simple and low-cost process, enabling in-situ remediation of PAH-contaminated soil without impacting or damaging the surrounding environment. It also demonstrates good remediation effects on PAH-contaminated soil and is applicable to the remediation of organically contaminated soil. However, natural antibacterial building blocks such as indole-3-acetic acid possess significant structural defects, including insufficient physicochemical properties, poor interfacial bonding with substrates, poor molecular water solubility, difficulty in fully exerting antibacterial activity, and difficulty in maintaining long-term antibacterial effects. These problems greatly limit their application in practical production. In contrast, polymeric antibacterial materials, with their good chemical stability, excellent antibacterial properties, lower cost, and higher utilization rate, show broad application prospects. Therefore, how to conduct directional structural design and performance optimization of natural antibacterial building blocks through precise chemical modification and advanced polymerization technology has become a key technical means to overcome this bottleneck.

[0004] In recent years, covalent grafting modification of natural antibacterial active units with bio-based polymer backbones has become an important research direction for constructing efficient, safe, and environmentally friendly antibacterial materials, providing a feasible path for developing novel materials that combine biosafety, processing stability, and long-lasting antibacterial capabilities. Research has found that a novel soluble oxidized starch-based nonionic antibacterial polymer prepared by grafting indoleacetic acid monomers onto oxidized corn starch exhibits high antibacterial activity and non-leaching properties (X. Dang, et al. New indoleacetic acid-functionalized soluble oxidized starch-based nonionic biopolymers as natural antibacterial materials. International Journal of Biological Macromolecules, 2023, 242: 125071.). Invention patent CN114702618A discloses a method for preparing indoleacetic acid-modified acrylic fluoropolymer and its coating. It combines the low surface energy characteristics of fluoropolymers with the antifouling properties of indole derivatives. Through free radical polymerization and nucleophilic ring-opening reactions of epoxy groups and amino groups, indoleacetic acid-modified acrylic fluoropolymer is prepared. This polymer can improve the antifouling performance of the coating, reduce diatom adhesion, and has good antibacterial and anti-algae capabilities. Furthermore, research reports that grafting cellulose with indoleacetic acid as a functional unit has synthesized a soluble cellulose-based nonionic biopolymer for use in natural antimicrobial materials. This biopolymer exhibits good water solubility and nonionic properties, with inhibition zones larger than 22 mm in diameter against *Escherichia coli* and *Staphylococcus aureus*, demonstrating excellent antimicrobial performance and biocompatibility, without any leaching of antimicrobial components. It can be well blended with biodegradable polymers such as polyvinyl alcohol to prepare composite membrane materials with balanced mechanical and antimicrobial properties (X. Dang, et al. Sustainable one-pot synthesis of novel soluble cellulose-based nonionic biopolymers for natural antimicrobial materials. Chemical Engineering Journal, 2023, 468:143810.). Invention patent CN 116854830A discloses a starch-indoleacetic acid derivative, its preparation method, and its applications. Indoleacetic acid can activate aromatic hydrocarbon receptors to exert an immunomodulatory effect, which, combined with the regulatory effect of short-chain fatty acids released from starch through intestinal flora fermentation, provides a product that synergistically exerts immunomodulatory effects through multiple immune system signaling pathways.Invention patent CN 102702565A relates to a method for preparing an indoleacetic acid molecularly imprinted polymer and its application, which is suitable for the enrichment and analysis of auxins in plant samples. This molecularly imprinted polymer is simple to prepare, has controllable thickness, strong selectivity, good enrichment effect, and can be reused repeatedly. However, natural antibacterial materials still have many limitations in practical applications, such as insufficient structural stability, susceptibility of antibacterial effects to environmental influences, poor processing performance, and difficulty in large-scale preparation. These problems greatly restrict their promotion and application in the materials field. In contrast, synthetic polymeric antibacterial materials have shown broad application prospects due to their good chemical stability, excellent antibacterial properties, low cost, and high utilization rate. Therefore, how to conduct directional structural design and performance optimization of natural antibacterial building blocks through precise chemical modification and advanced polymerization technology, and achieve the organic combination of the advantages of natural products and the controllability of polymer structures, has become a key technical means to break through the bottleneck of the development of natural antibacterial materials. Furthermore, indole-3-acetic acid (IAA) lacks polymerization active sites in its molecular unit, making it unable to directly participate in polymerization reactions to form polymeric antibacterial materials. This difficulty in immobilizing and loading antibacterial active sites constitutes a core obstacle to its application in the field of antibacterial materials. How to impart polymerization activity to IAA through targeted molecular modification while fully preserving its antibacterial activity has become a crucial scientific problem that urgently needs to be solved.

[0005] Currently, research on the modification of indole-3-acetic acid (IAA) largely focuses on small-molecule grafting modification and polymerization. Existing antibacterial polymer materials are mostly prepared using traditional free radical polymerization techniques, which suffer from problems such as wide molecular weight distribution, uncontrollable chain segment structure, and uneven distribution of antibacterial active sites, making it difficult to achieve synergistic optimization of material antibacterial properties and substrate compatibility. Reversible addition-fragmentation chain transfer (RAFT) polymerization, as a living and controllable free radical polymerization technique, has advantages such as mild reaction conditions, a wide range of applicable monomers, and precise control over polymer molecular weight and chain segment structure. It can effectively overcome the shortcomings of traditional polymerization techniques, providing technical support for the preparation of structurally regular and performance-tunable antibacterial polymers. Based on this, using natural indole-3-acetic acid as the antibacterial building block, combined with esterification modification and RAFT polymerization techniques, to develop novel polymeric antibacterial materials suitable for agricultural antibacterial needs has become a research direction that combines scientific rigor and practicality, and also provides new ideas for solving the application challenges of natural antibacterial building blocks. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide an indole acetate monomer with excellent biocompatibility.

[0007] Another technical problem to be solved by the present invention is to provide a high-performance polymer antibacterial material containing the monomer unit (i.e., indole acetate monomer unit).

[0008] To solve the above problems, the present invention provides an indole acetate monomer, characterized in that the indole acetate monomer has the following structure: Where: R1 is -CH3 or -H; x = 2 ~ 4.

[0009] A polymeric antibacterial material containing the indoleacetic acid monomer unit as described above, characterized in that the polymeric antibacterial material has the following structure: Where: R1 is -CH3 or -H; R2 is -CN or -CH3; x = 2 ~ 4; n is the degree of polymerization.

[0010] The method for synthesizing an indoleacetic acid ester monomer as described above is characterized by the following steps: In a container equipped with heating and stirring devices, indoleacetic acid and a halogenated hydrocarbon solvent are added and thoroughly stirred until dissolved. Then, a condensing agent and a pyridine catalyst are added, and the mixture is stirred at 10–40 °C for 5–25 min to obtain a homogeneous mixed solution. Next, an acrylate reagent is added to the above mixed solution, and the reaction is continued at 30–50 °C for 15–30 h with stirring. The mixture is then cooled in an ice-water bath at -5–0 °C for 0.5–5 h. Finally, the cooled mixture is filtered, extracted 2–5 times with saturated NaCl solution, and the organic phase is collected. Excess solvent is removed by rotary evaporation, and the resulting pale yellow oily liquid after column chromatography purification is the indoleacetic acid ester monomer.

[0011] The halogenated hydrocarbon solvent is one of dichloromethane, chloroform, carbon tetrachloride, or 1-bromopropane, and the ratio of the halogenated hydrocarbon solvent to indoleacetic acid is 10.00~25.00 mL: 1.00~2.50 g; the condensing agent is a carbodiimide dehydrating condensing agent, namely one of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, N,N-diisopropylcarbodiimide, or N,N-dicyclohexylcarbodiimide, and the mass of the condensing agent is 50%~110% of the mass of indoleacetic acid; the pyridine catalyst is one of pyridine, 3-methylpyridine, or 4-dimethylaminopyridine, and the mass of the pyridine catalyst is 5%~15% of the mass of indoleacetic acid; the acrylate reagent is one of hydroxyethyl acrylate / hydroxypropyl acrylate / hydroxybutyl acrylate or hydroxyethyl methacrylate / hydroxypropyl acrylate / hydroxybutyl acrylate, and the mass ratio of the acrylate reagent to indoleacetic acid is 1.00~ 3.00 g: 1.00~2.50 g.

[0012] The method for synthesizing a polymeric antibacterial material as described above is characterized by the following steps: First, a RAFT small molecule chain transfer agent is prepared. Then, the RAFT small molecule chain transfer agent, indole acetate monomer, oil-soluble initiator, and amide solvent are added to a Schlenk tube and magnetically stirred to ensure uniform mixing of the reaction substrate. Next, the sealed Schlenk tube is immersed in liquid nitrogen and subjected to several freeze-thaw cycles, with the final cycle involving filling the system with an inert gas. The specific freeze-thaw process is as follows: after the solvent is completely frozen, the stopcock is opened to create a vacuum for 1-5 minutes. The reaction flask is then closed, and thawing is allowed until the solvent is completely thawed. This process is repeated 2-5 times. Then, the reaction is stirred at 60-80 °C for 12-36 h. After the reaction is complete, the Schlenk tube is immersed in liquid nitrogen to quench the reaction. After thawing, the reaction mixture is dialyzed against deionized water for 1-4 days, and the product is collected and freeze-dried at -70--50 °C to obtain the precipitate, which is the polymeric antibacterial material containing indole acetate monomer units.

[0013] The RAFT small molecule chain transfer agent is prepared by the following method: In a container equipped with a pre-cooling, stirring, and nitrogen protection device, n-dodecyl mercaptan is dissolved in a ketone solvent at 0-5 °C, and a phase transfer catalyst is added. The mixture is stirred magnetically until homogeneous. Subsequently, an alkaline aqueous solution is added dropwise, and stirring is continued for 15-30 min. Then, a carbon disulfide solution, a haloalkane reagent, and an aqueous solution of an alkaline reagent are added sequentially. After all substances have been added, the reaction is stirred under a nitrogen atmosphere for 12-36 h. After the reaction is completed, distilled water is added to quench the reaction and completely dissolve the precipitate in the solution. Then, an acidic solvent is added dropwise to adjust the pH of the solution to 2-6. The resulting mixed solution is vacuum filtered to obtain a precipitate. This precipitate is dissolved in an alcohol solvent, filtered, rotary evaporated, and pre-dried. The pre-dried solid is dissolved in a precipitant. After partial precipitation, the product is further cooled and crystallized at -20 to -5 °C. The solid product is obtained by vacuum filtration. This solid product is then subjected to 40-85 °C... After vacuum drying at ℃ to constant weight, a yellow solid is obtained, which is the RAFT small molecule chain transfer agent.

[0014] The ketone solvent is one of acetone, butanone, or cyclohexanone, and the mass ratio of the ketone solvent to n-dodecyl mercaptan is 50.00~65.00 g: 15.00~30.00 g; the phase transfer catalyst is one of hexadecyltrimethylammonium bromide, benzyltriethylammonium chloride, or methyltrioctylammonium chloride, and the mass of the phase transfer catalyst is 3.0%~8.0% of the mass of n-dodecyl mercaptan; both the alkaline aqueous solution and the aqueous solution of the alkaline reagent refer to aqueous solutions prepared with sodium hydroxide, potassium hydroxide, or triethylamine, with a mass concentration of 35%~55%; the mass ratio of the alkaline aqueous solution to n-dodecyl mercaptan is 5g~20g: 15.00~30.00 g; the mass ratio of the aqueous solution of the alkaline reagent to n-dodecyl mercaptan is 30.00~45.00g: 15.00~30.00g. g; the carbon disulfide solution refers to a solution with a concentration of 40.00% to 50.00% formed by dissolving carbon disulfide in a ketone solvent, wherein the mass of carbon disulfide is 20% to 40% of the mass of n-dodecyl mercaptan; the halogenated hydrocarbon solvent is one of dichloromethane, chloroform, carbon tetrachloride, or 1-bromopropane, wherein the mass of the halogenated hydrocarbon solvent is 75% to 90% of the mass of n-dodecyl mercaptan; the acid solvent is one of concentrated acid, concentrated nitric acid, or concentrated sulfuric acid; the alcohol solvent is one of anhydrous ethanol, isopropanol, or methanol, wherein the ratio of the alcohol solvent to n-dodecyl mercaptan is 100 to 250 mL: 15.00 to 30.00 g; the precipitant is one of n-hexane, n-octane, or petroleum ether, wherein the ratio of the precipitant to n-dodecyl mercaptan is 150 to 250 mL: 15.00 to 30.00 g.

[0015] The mass of the indoleacetic acid ester monomer is 2000% to 3500% of the mass of the RAFT small molecule chain transfer agent; the oil-soluble initiator is one of benzoyl peroxide, azobisisobutyronitrile, or azobisisoheptanenitrile, and the mass of the oil-soluble initiator is 1.0% to 5.0% of the mass of the RAFT small molecule chain transfer agent; the amide solvent is one of N-methylformamide, N,N-dimethylformamide, or N,N-dimethylacetamide, and the mass ratio of the amide solvent to the RAFT small molecule chain transfer agent is 5.00 to 20.00 g: 50 to 250 mg.

[0016] The inert gas refers to nitrogen or argon.

[0017] Compared with the prior art, the present invention has the following advantages: 1. This invention uses biomass indoleacetic acid, which is biocompatible, widely available, and renewable, as a raw material to synthesize a novel indoleacetic acid ester monomer via Steglich esterification.

[0018] 2. This invention uses indoleacetic acid monomer with excellent biocompatibility as the functional component and employs RAFT polymerization to prepare a polymer antibacterial material with excellent antibacterial activity. The preparation process of this material is simple, the process is highly controllable, and it is easy to scale up production.

[0019] 3. The antibacterial material prepared by this invention uses green, non-toxic, widely available, and renewable raw materials. Its excellent biocompatibility and antibacterial properties have broad application prospects in antibacterial coatings, agricultural antibacterial applications, and other fields. Attached Figure Description

[0020] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0021] Figure 1 The proton nuclear magnetic resonance spectrum of the indoleacetic acid ester monomer prepared in Example 1 of this invention ( 1 (H NMR) image.

[0022] Figure 2 The image shows the Fourier transform infrared (FT-IR) spectrum of the indole acetate monomer prepared in Example 1 of this invention.

[0023] Figure 3 The proton nuclear magnetic resonance spectrum of the RAFT small molecule chain transfer agent prepared in Example 1 of this invention ( 1 (H NMR) image.

[0024] Figure 4 The image shows the infrared spectrum (FT-IR) of the RAFT small molecule chain transfer agent prepared in Example 1 of this invention.

[0025] Figure 5 The nuclear magnetic resonance hydrogen spectrum of the polymer antibacterial material prepared in Example 1 of this invention ( 1 (H NMR) image.

[0026] Figure 6 The image shows the Fourier transform infrared (FT-IR) spectrum of the polymer antibacterial material prepared in Example 1 of this invention.

[0027] Figure 7 This is a scanning electron microscope (SEM) image of the polymer antibacterial material prepared in Example 1 of the present invention.

[0028] Figure 8 This is a photograph of an antibacterial plate of the indoleacetic acid monomer and polymer antibacterial material prepared in Example 1 of the present invention. Detailed Implementation

[0029] An indole acetate monomer having the following structure: Where: R1 is -CH3 or -H; x = 2 ~ 4.

[0030] The synthesis method is as follows: In a container equipped with a heating and stirring device, indoleacetic acid and a haloalkanes solvent are added and stirred thoroughly to dissolve. Then, a condensing agent and a pyridine catalyst are added, and the mixture is stirred at 10-40 °C for 5-25 min to obtain a homogeneous mixed solution. Next, acrylate reagents are added to the above mixed solution, and the reaction is continued to be stirred at 30-50 °C for 15-30 h. Then, the mixture is cooled in an ice-water bath at -5-0 °C for 0.5-5 h. Finally, the cooled mixture is filtered, extracted 2-5 times with saturated NaCl solution, the organic phase is collected, excess solvent is removed by rotary evaporation, and purified by column chromatography. The resulting pale yellow oily liquid is the indoleacetic acid monomer.

[0031] The solvent is selected from the following: a halogenated hydrocarbon solvent, specifically dichloromethane, chloroform, carbon tetrachloride, or 1-bromopropane, with a ratio of 10.00–25.00 mL to 1.00–2.50 g of indoleacetic acid; a carbodiimide dehydrating condensing agent, specifically 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, N,N-diisopropylcarbodiimide, or N,N-dicyclohexylcarbodiimide, with a mass of 50%–110% of the mass of indoleacetic acid; a pyridine catalyst, specifically pyridine, 3-methylpyridine, or 4-dimethylaminopyridine, with a mass of 5%–15% of the mass of indoleacetic acid; and an acrylate reagent, specifically hydroxyethyl acrylate / hydroxypropyl acrylate / hydroxybutyl acrylate or hydroxyethyl methacrylate / hydroxypropyl acrylate / hydroxybutyl acrylate, with a mass ratio of 1.00–2.50 g to indoleacetic acid. 3.00 g: 1.00 ~ 2.50 g.

[0032] A polymeric antibacterial material containing the above-mentioned indoleacetic acid monomer unit, the polymeric antibacterial material having the following structure: Where: R1 is -CH3 or -H; R2 is -CN or -CH3; x = 2 ~ 4; n is the degree of polymerization.

[0033] Its synthesis method refers to: First, prepare the RAFT small molecule chain transfer agent: In a container equipped with pre-cooling, stirring, and nitrogen protection devices, dissolve n-dodecyl mercaptan in a ketone solvent at 0-5 °C, and continue to add the phase transfer catalyst, stirring magnetically to ensure uniform mixing; then, gradually add an alkaline aqueous solution, stirring for 15-30 min; then add carbon disulfide solution, haloalkane reagent, and aqueous solution of alkaline reagent in sequence, and after all substances have been added, stir the reaction under a nitrogen atmosphere for 12-36 h; after the reaction is complete, add distilled water to quench the reaction and completely dissolve the precipitate in the solution, then add an acidic solvent to adjust the pH of the solution to 2-6; the resulting mixed solution is vacuum filtered to obtain the precipitate, which is dissolved in an alcohol solvent, filtered, and the filtrate is rotary evaporated to remove the solvent, and the mixture is pre-dried; then, the pre-dried solid is dissolved in the precipitant, and after partial precipitation, it is further cooled and crystallized at -20 to -5 °C, and the solid product is obtained by vacuum filtration. This solid product is then subjected to 40- After vacuum drying at 85℃ to constant weight, a yellow solid is obtained, which is the RAFT small molecule chain transfer agent.

[0034] Then, RAFT small molecule chain transfer agent, indole acetate monomer, oil-soluble initiator, and amide solvent are added to a Schlenk tube and magnetically stirred to ensure uniform mixing of the reaction substrate. Next, the sealed Schlenk tube is immersed in liquid nitrogen and subjected to several freeze-thaw cycles, with the final cycle filled with an inert gas (nitrogen or argon). The specific freeze-thaw process is as follows: after the solvent is completely frozen, the stopcock is opened to evacuate for 1 to 5 minutes; the reaction flask is closed, and thawing is allowed until the solvent is completely thawed, repeating this process 2 to 5 times; then, the reaction is stirred at 60 to 80 °C for 12 to 36 hours; after the reaction is complete, the Schlenk tube is immersed in liquid nitrogen to quench the reaction; after thawing, the reaction mixture is dialyzed against deionized water for 1 to 4 days, the product is collected, and freeze-dried at -70 to -50 °C to obtain the precipitate, which is the polymer antibacterial material containing indole acetate monomer units.

[0035] Wherein: the ketone solvent is one of acetone, butanone, or cyclohexanone, and the mass ratio of the ketone solvent to n-dodecyl mercaptan is 50.00~65.00 g: 15.00~30.00 g; the phase transfer catalyst is one of hexadecyltrimethylammonium bromide, benzyltriethylammonium chloride, or methyltrioctylammonium chloride, and the mass of the phase transfer catalyst is 3.0%~8.0% of the mass of n-dodecyl mercaptan; the alkaline aqueous solution and the aqueous solution of the alkaline reagent both refer to aqueous solutions prepared with sodium hydroxide, potassium hydroxide, or triethylamine, with a mass concentration of 35%~55%; the mass ratio of the alkaline aqueous solution to n-dodecyl mercaptan is 5 g~20 g: 15.00~30.00 g; the mass ratio of the aqueous solution of the alkaline reagent to n-dodecyl mercaptan is 30.00~45.00 g: 15.00~30.00 g; the carbon disulfide solution refers to a solution of carbon disulfide dissolved in a ketone solvent with a concentration of 40.00%~ The solution is 50.00% in volume, with carbon disulfide accounting for 20% to 40% of the mass of n-dodecyl mercaptan; the halogenated hydrocarbon solvent is one of dichloromethane, chloroform, carbon tetrachloride, or 1-bromopropane, accounting for 75% to 90% of the mass of n-dodecyl mercaptan; the acid solvent is one of concentrated acid, concentrated nitric acid, or concentrated sulfuric acid; the alcohol solvent is one of anhydrous ethanol, isopropanol, or methanol, with the ratio of the alcohol solvent to n-dodecyl mercaptan being 100 to 250 mL: 15.00 to 30.00 g; the precipitant is one of n-hexane, n-octane, or petroleum ether, with the ratio of the precipitant to n-dodecyl mercaptan being 150 to 250 mL: 15.00 to 30.00 g.

[0036] The mass of the indoleacetic acid ester monomer is 2000% to 3500% of the mass of the RAFT small molecule chain transfer agent; the oil-soluble initiator is one of benzoyl peroxide, azobisisobutyronitrile, or azobisisoheptanenitrile, and the mass of the oil-soluble initiator is 1.0% to 5.0% of the mass of the RAFT small molecule chain transfer agent; the amide solvent is one of N-methylformamide, N,N-dimethylformamide, or N,N-dimethylacetamide, and the mass ratio of the amide solvent to the RAFT small molecule chain transfer agent is 5.00 to 20.00 g: 50 to 250 mg.

[0037] Example 1: A method for synthesizing an indoleacetic acid monomer and a polymeric antibacterial material containing the monomer unit, comprising the following steps: (1) Preparation of indoleacetic acid ester monomer: In a flask equipped with a heating bath and a stirring device, 1.65 g of indoleacetic acid and 15 mL of 1-bromopropane were added and stirred thoroughly to dissolve. Then, 1.25 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and 0.20 g of 3-methylpyridine were added, and the mixture was stirred at 20 °C for 7 min to obtain a homogeneous mixed solution. Next, 1.75 g of hydroxyethyl acrylate was added to the above mixed solution, and the reaction was carried out by continuous stirring at 30 °C for 22 h. Then, the mixture was cooled in an ice-water bath at -5 °C for 0.5 h. Subsequently, the mixture was filtered, extracted twice with saturated NaCl solution, and the organic phase was collected after liquid-liquid extraction. Excess solvent was removed by rotary evaporation, and the mixture was purified by column chromatography to obtain a pale yellow oily liquid, which is the indoleacetic acid monomer.

[0038] (2) Preparation of polymer antibacterial materials: First, the RAFT small molecule chain transfer agent was prepared: In a three-necked flask equipped with a pre-cooling, stirring, and nitrogen protection device, 19.75 g of n-dodecyl mercaptan, 58.35 g of butanone, and 0.95 g of methyltrioctylammonium chloride were added. The mixture was pre-cooled to 0 °C and magnetically stirred until homogeneous. Then, 8.50 g of potassium hydroxide aqueous solution was added dropwise. After stirring for 15 min, a mixture of carbon disulfide and butanone, 16.50 g of carbon tetrachloride, and 39.00 g of potassium hydroxide aqueous solution were added sequentially. After all substances were added, the reaction was stirred under a nitrogen atmosphere for 20 h. After the reaction was completed, 170 mL of distilled water was added to stop the reaction and to completely dissolve the precipitate in the solution. Then, 60 mL of concentrated hydrochloric acid was added dropwise to adjust the pH of the solution to 2. The resulting mixed solution was vacuum filtered, the precipitate was collected, and dissolved in 100 mL of water. The mixture was filtered through mL of methanol, and the solvent was removed by rotary evaporation. The mixture was then pre-dried. Subsequently, the pre-dried solid was dissolved in 150 mL of n-octane and cooled to crystallize at -20 °C. The product was obtained by vacuum filtration and then dried under vacuum at 40 °C to constant weight to obtain a yellow solid, which is the RAFT small molecule chain transfer agent.

[0039] Next, 65 mg of RAFT small molecule chain transfer agent, 1300 mg of indoleacetic acid monomer, 1.5 mg of azobisisobutyronitrile, and 10.00 g of N-methylformamide were added to a Schlenk tube and magnetically stirred to mix the reaction substrate evenly. Subsequently, the sealed Schlenk tube was immersed in liquid nitrogen and subjected to several freeze-thaw cycles, with the last cycle filling the system with inert gas. The specific freeze-thaw process was as follows: after the solvent was completely frozen, the stopcock was opened to evacuate for 1 min; the reaction flask was closed, and thawing was carried out until the solvent was completely thawed, repeating this process 2 to 5 times; then, the reaction was stirred at 65 °C for 21 h; after the reaction was completed, the Schlenk tube was immersed in liquid nitrogen to quench the reaction; after thawing, the reaction mixture was dialyzed with deionized water for 2 days, the product was collected, and the precipitate was obtained by freeze-drying at -70 °C, which is the polymer antibacterial material.

[0040] The indole acetate monomer and polymer antibacterial materials prepared in Example 1 were characterized and analyzed, and their antibacterial properties were tested.

[0041] [Hydrogen NMR Spectroscopy] By nuclear magnetic resonance hydrogen spectrum ( 1 The chemical structure of the indoleacetic acid monomer was analyzed by 1H NMR, and the results are as follows: Figure 1 As shown in the figure, the singlet at 12.87 ppm corresponds to the elution of hydrogen (-NH-) on the indole ring; the multiplets in the 7.0–7.8 ppm range correspond to the elution of aromatic hydrogen (b–f positions -H-) on the indole ring, benzene ring, and pyrrole ring; the two singlets at 6.1–6.2 ppm and 5.6–5.7 ppm are attributed to the elution of double-bonded hydrogen (=CH-) on the methacrylic acid side chain; the two sets of triplets in the 4.1–4.3 ppm range correspond to the elution of methylene hydrogen (-OCH2CH2O-); and the strong peak near 2.5 ppm is the elution of residual hydrogen from the solvent DMSO. This demonstrates the successful synthesis of the indole acetate monomer.

[0042] pass 1 The prepared RAFT small molecule chain transfer agent was characterized by H NMR, such as Figure 3 As shown. 1In the 1H NMR spectrum, the singlet at 12.87 ppm corresponds to the carboxyl hydrogen (-COOH); the triplet at 3.26–3.29 ppm corresponds to the thiomethylene hydrogen (-CH2S-); the singlet at 1.60 ppm corresponds to the methyl hydrogen (-C(CH3)2); the multiplet at 1.22 ppm corresponds to the methylene hydrogen (-CH2-); and the triplet at 0.83–0.85 ppm corresponds to the typical terminal methyl hydrogen (-CH3). This demonstrates the successful synthesis of the RAFT small chain transfer agent.

[0043] Finally, through 1 H NMR was used to characterize the structure of the prepared polymer antibacterial materials, such as Figure 5 As shown. 1 In the 1H NMR spectrum, the singlet at 12.87 ppm corresponds to the elution of carboxyl hydrogen (-COOH); the singlet near 11.0 ppm corresponds to the elution of hydrogen on the indole ring (-NH-); the multiplets in the 7.0 ~ 7.8 ppm range correspond to the elution of aromatic hydrogen on the indole ring (i ~ m positions -H- on the indole benzene ring and pyrrole ring); the weak peak near 6.0 ppm is attributed to the elution of methine hydrogen (-CH(S-)-) connected to the thiocarbonyl group on the main chain; the two sets of multiplets in the 4.0 ~ 4.3 ppm range correspond to the elution of methylene hydrogen (-OCH2CH2O-) connected by the ester bond; the strong peak near 3.3 ppm is the elution of residual hydrogen from the solvent DMSO; the multiplets in the 1.8 ~ 2.0 ppm range correspond to the elution of alkyl methine and methyl hydrogen (-C(CH3)-) on the main chain of the polymer antibacterial material; and the peaks in the 1.2 ~ 1.4 ppm range correspond to the elution of the alkyl methine and methyl hydrogen (-C(CH3)-) on the main chain of the polymer antibacterial material. The multiplets in the ppm range are due to the methylene hydrogen (-(CH2) in the long-chain alkyl group at the RAFT terminal. 10 The peak at -) indicates the presence of methyl hydrogen (-CH3) at the terminal alkyl group of the RAFT terminal group, and the triplet in the 0.8 ~ 0.9 ppm range indicates the presence of methyl hydrogen (-CH3) at the terminal alkyl group of the RAFT terminal group. This confirms the successful synthesis of the polymer antibacterial material.

[0044] Infrared Spectroscopy The structure of the prepared indole acetate monomer was characterized by Fourier transform infrared spectroscopy (FT-IR), such as... Figure 2 As shown. Among them, at 3417 cm... -1 The strong absorption peak is attributed to the stretching vibration of NH on the indole ring, proving the existence of the indole ring structure in the molecule; 2958 cm⁻¹ -1 and 2885 cm -1 The absorption peak corresponds to the saturated CH stretching vibrations of -CH2 and -CH3; 1725 cm⁻¹ -1 The strong absorption peak at 1637 cm⁻¹ is due to the stretching vibration of C=O, proving the presence of C=O in the molecule; -1The absorption peak is attributed to the stretching vibration of C=C, where the double bond is conjugated with C=O, causing a slight shift in peak position to a lower wavenumber; 1550 ~ 1450 cm⁻¹ -1 The multiple peaks in the interval correspond to the skeletal vibrations of the aromatic C=C ring of the indole ring; 1175 cm⁻¹ -1 and 1077 cm -1 The stretching vibrations attributed to COC, together with C=O, prove the existence of the ester bond structure; 742 cm -1 This is an out-of-plane bending vibration of the aromatic CH group of the indole ring. In summary, the indole acetate monomer has been successfully synthesized.

[0045] via FT-IR ( Figure 4 This further validated the successful synthesis of the RAFT small molecule chain transfer agent. In the FT-IR spectrum, 3407 cm⁻¹ -1 The absorption peak at 2924 cm⁻¹ corresponds to the stretching vibration of -OH. -1 With 2852 cm -1 The absorption peaks at 1720 cm⁻¹ are attributed to the saturated CH stretching vibrations of -CH₃ and -CH₂-, respectively; -1 The strong absorption peak at 1282 cm⁻¹ is a characteristic stretching vibration of C=O. -1 The absorption peak at 1065 cm⁻¹ corresponds to the stretching vibration of the -CS- structure of the dithioester; -1 The absorption peak at that point is attributed to the characteristic vibration of C=S. In conclusion, the RAFT small molecule chain transfer agent has been successfully synthesized.

[0046] The characteristic absorption peaks of the polymer antibacterial material were analyzed by FT-IR, and the results are as follows: Figure 6 As shown. Among them, at 3428cm -1 The broad and strong absorption peaks appearing in the region are attributed to the stretching vibrations of NH on the indole ring and the stretching vibrations of OH on the carboxyl group, which overlap to form the broad peaks; 2931 cm⁻¹ -1 and 2869 cm -1 The absorption peak corresponds to the long-chain alkyl (-C) 12 H 25 The stretching vibrations of saturated CH groups in the main chain of polymer antibacterial materials; 1685 cm⁻¹ -1 The strong absorption peak at 1600 ~ 1400 cm⁻¹ is attributed to the C=O stretching vibration of the ester group. -1 The multiple peaks in the region mainly originate from the aromatic C=C skeleton vibration of the indole ring; 1257 cm⁻¹ -1 The absorption peak at 1250 ~ 1000 cm⁻¹ is attributed to the stretching vibration of the SCS. -1The strong multiplets in the range are attributed to the stretching vibration of COC. In summary, the chemical structures of both the indole acetate monomer and the RAFT chain transfer agent are present, and the disappearance of the C=C peak of the indole acetate monomer after polymerization indicates that the polymer antibacterial material was successfully prepared.

[0047] Microscopic morphology The microstructure of the polymer antibacterial material prepared in this invention was tested using scanning electron microscopy (SEM). Figure 7 The results showed that the material consists of spherical nanoparticles with a diameter of 100-300 nm. After aggregation and stacking, the nanoparticles further form a loose porous network structure with a size of several micrometers. There are obvious connection sites and interconnected pores between the particles, and the constructed three-dimensional network framework significantly increases the specific surface area of ​​the material, providing a structural basis for the full exposure of antibacterial active sites. Combined with its chemical structure analysis, it is believed that this morphology may originate from the self-assembly behavior of linear copolymers in the organic phase through hydrophobic association. The high specific surface area and the fully exposed active sites produce a synergistic effect, providing structural protection for the material to efficiently bind to bacteria, disrupt bacterial cell membranes, and interfere with bacterial metabolic processes, thereby significantly improving its antibacterial properties.

[0048] [Antibacterial properties] Select Gram-negative bacteria (Escherichia coli, E. coli ) and Gram-positive bacteria (Staphylococcus aureus, S. aureus Using this strain as a test strain, the antibacterial activity of indoleacetic acid monomer and its polymeric antibacterial materials was semi-quantitatively evaluated using the plate colony counting method. The results are as follows: Figure 8 As shown in the figure, both bacteria grew vigorously on the control group plates, with numerous and evenly distributed colonies. The colony count in the indole acetate monomer treatment group was somewhat reduced compared to the control group, exhibiting a weak to moderate antibacterial effect. However, almost no colonies grew on the plates treated with the novel polymer antibacterial material prepared in this invention, indicating that it exhibits extremely strong antibacterial ability against both bacteria. This demonstrates that the polymer antibacterial material obtained after polymerization has significantly enhanced antibacterial activity compared to the indole acetate monomer, and its antibacterial effect against... E. coli and S. aureus The antibacterial rates were 99.9% and 100%, respectively, demonstrating their broad-spectrum and highly effective antibacterial potential.

[0049] It is worth noting that indole acetate monomers only exhibit limited antibacterial activity, while polymer antibacterial materials obtained through polymerization reactions show excellent antibacterial properties. This indicates that the assembly and enrichment effect of polymer chains is the key to achieving efficient antibacterial activity.

[0050] Example 2 A method for synthesizing an indoleacetic acid monomer and a polymeric antibacterial material containing the monomer unit, comprising the following steps: (1) Preparation of indoleacetic acid ester monomer: In a flask equipped with a heating bath and a stirring device, 1.95 g of indoleacetic acid and 20 mL of dichloromethane were added and stirred thoroughly to dissolve. Then, 1.45 g of N,N-diisopropylcarbodiimide and 0.25 g of pyridine were added, and the mixture was stirred at 24 °C for 10 min to obtain a homogeneous mixed solution. Next, 2.15 g of hydroxypropyl methacrylate was added to the above mixed solution, and the mixture was stirred continuously at 35 °C for 25 h, and then cooled in an ice-water bath at -2 °C for 1 h. Subsequently, the mixture was filtered, extracted four times with saturated NaCl solution, and the organic phase was collected after separation extraction. Excess solvent was removed by rotary evaporation, and the mixture was purified by column chromatography to obtain a pale yellow oily liquid, which is the indoleacetic acid monomer.

[0051] (2) Preparation of polymer antibacterial materials: First, the RAFT small molecule chain transfer agent was prepared: In a three-necked flask equipped with a pre-cooling, stirring, and nitrogen gas protection device, 20.50 g of n-dodecyl mercaptan, 59.65 g of acetone, and 1.00 g of benzyltriethylammonium chloride were added. The mixture was pre-cooled to 2 °C and magnetically stirred until homogeneous. Then, 9.00 g of sodium hydroxide aqueous solution was added dropwise. After stirring for 20 min, a mixture of 20.00 g of carbon disulfide and acetone, 17.50 g of dichloromethane, and 39.50 g of sodium hydroxide aqueous solution were added sequentially. After all substances were added, the reaction was stirred under a nitrogen atmosphere for 26 h. After the reaction was completed, 200 mL of distilled water was added to stop the reaction and to completely dissolve the precipitate in the solution. Then, 75 mL of concentrated sulfuric acid was added dropwise to adjust the pH of the solution to 3. The resulting mixed solution was vacuum filtered, the precipitate was collected, and dissolved in 150 mL of water. The mixture was filtered in mL of isopropanol, and the solvent was removed by rotary evaporation. The mixture was then pre-dried. Subsequently, the pre-dried solid was dissolved in 200 mL of petroleum ether, cooled and crystallized at -10 °C, and the product was obtained by vacuum filtration. The product was then dried under vacuum at 55 °C to constant weight to obtain a yellow solid, which is the RAFT small molecule chain transfer agent.

[0052] Next, 175 mg of RAFT small molecule chain transfer agent, 4375 mg of indole acetate monomer, 3 mg of azobisisobutyronitrile, and 15.00 g of N,N-dimethylacetamide were added to a Schlenk tube and magnetically stirred to mix the reaction substrate evenly. Subsequently, the sealed Schlenk tube was immersed in liquid nitrogen and subjected to several freeze-thaw cycles, with the last cycle filling the system with inert gas. The specific freeze-thaw process was as follows: after the solvent was completely frozen, the stopcock was opened to evacuate for 3 minutes; the reaction flask was closed, and thawing was carried out until the solvent was completely thawed, repeating this process 2 to 5 times; then, the reaction was stirred at 70 °C for 23 h; after the reaction was completed, the Schlenk tube was immersed in liquid nitrogen to quench the reaction; after thawing, the reaction mixture was dialyzed against deionized water for 3 days, the product was collected, and the precipitate was obtained by freeze-drying at -65 °C, which is the polymer antibacterial material.

[0053] The prepared polymer antibacterial material showed inhibition rates of 99.9% and 100% against Escherichia coli and Staphylococcus aureus, respectively.

[0054] Example 3 A method for synthesizing an indoleacetic acid monomer and a polymeric antibacterial material containing the monomer unit, comprising the following steps: (1) Preparation of indoleacetic acid ester monomer: In a flask equipped with a heating bath and a stirrer, 2.35 g of indoleacetic acid and 25 mL of chloroform were added and stirred thoroughly to dissolve. Then, 1.65 g of N,N-dicyclohexylcarbodiimide and 0.30 g of 4-dimethylaminopyridine were added, and the mixture was stirred at 30 °C for 13 min to obtain a homogeneous mixed solution. Next, 2.25 g of hydroxybutyl acrylate was added to the above mixed solution, and the reaction was carried out by continuous stirring at 40 °C for 27 h, followed by cooling in an ice-water bath at 0 °C for 1.5 h. Subsequently, the mixture was filtered, extracted five times with saturated NaCl solution, and the organic phase was collected after separation extraction. Excess solvent was removed by rotary evaporation, and the solution was purified by column chromatography to obtain a pale yellow oily liquid, which is the indoleacetic acid monomer.

[0055] (2) Preparation of polymer antibacterial materials: First, the RAFT small molecule chain transfer agent was prepared: In a three-necked flask equipped with a pre-cooling, stirring, and nitrogen gas protection device, 21.00 g of n-dodecyl mercaptan, 60.25 g of cyclohexanone, and 1.05 g of hexadecyltrimethylammonium bromide were added. The flask was pre-cooled to 4°C and magnetically stirred until homogeneous. Then, 9.35 g of triethylamine aqueous solution was added dropwise. After stirring for 25 min, a mixture of 25.00 g of carbon disulfide and cyclohexanone, 18.20 g of chloroform, and 41.35 g of triethylamine aqueous solution were added sequentially. After all substances were added, the flask was sealed and stirred under a nitrogen atmosphere for 30 h. After the reaction was completed, 230 mL of distilled water was added to stop the reaction and to completely dissolve the precipitate in the solution. Then, 90 mL of concentrated nitric acid was added dropwise to adjust the pH of the solution to 5. The resulting mixed solution was vacuum filtered, the precipitate was collected, and dissolved in 180 mL of water. The mixture was filtered through 240 mL of anhydrous ethanol, and the solvent was removed by rotary evaporation. The mixture was then pre-dried. Subsequently, the pre-dried solid was dissolved in 240 mL of n-hexane and cooled to crystallize at -5 °C. The product was obtained by vacuum filtration and then dried under vacuum at 65 °C to constant weight to obtain a yellow solid, which is the RAFT small molecule chain transfer agent.

[0056] Next, 235 mg of RAFT small molecule chain transfer agent, 7050 mg of indoleacetic acid monomer, 4 mg of benzoyl peroxide, and 20.00 g of N,N-dimethylformamide were added to a Schlenk tube and magnetically stirred to mix the reaction substrate evenly. Subsequently, the sealed Schlenk tube was immersed in liquid nitrogen and subjected to several freeze-thaw cycles, with the last cycle filling the system with inert gas. The specific freeze-thaw process was as follows: after the solvent was completely frozen, the stopcock was opened to evacuate for 5 min; the reaction flask was closed, and thawing was carried out until the solvent was completely thawed, repeating this process 2 to 5 times; then, the reaction was stirred at 80 °C for 32 h; after the reaction was completed, the Schlenk tube was immersed in liquid nitrogen to quench the reaction; after thawing, the reaction mixture was dialyzed against deionized water for 4 days, the product was collected, and the precipitate was obtained by freeze-drying at -55 °C, which is the polymer antibacterial material.

[0057] The prepared polymer antibacterial material showed inhibition rates of 99.9% and 100% against Escherichia coli and Staphylococcus aureus, respectively.

Claims

1. An indoleacetic acid ester monomer, characterized in that: The indoleacetic acid ester monomer has the following structure: Where: R1 is -CH3 or -H; x = 2 ~ 4.

2. A polymeric antibacterial material containing the indoleacetic acid monomer unit as described in claim 1, characterized in that: The polymer antibacterial material has the following structure: Where: R1 is -CH3 or -H; R2 is -CN or -CH3; x = 2 ~ 4; n is the degree of polymerization.

3. The method for synthesizing an indole acetate monomer as described in claim 1, characterized in that: The method involves adding indoleacetic acid and a halogenated hydrocarbon solvent to a container equipped with heating and stirring devices, stirring thoroughly to dissolve them, then adding a condensing agent and a pyridine catalyst, and stirring at 10-40 °C for 5-25 min to obtain a homogeneous mixed solution. Next, an acrylate reagent is added to the above mixed solution, and the reaction is continued to be stirred at 30-50 °C for 15-30 h, followed by cooling in an ice-water bath at -5-0 °C for 0.5-5 h. Finally, the cooled mixture is filtered, extracted 2-5 times with saturated NaCl solution, the organic phase is collected, excess solvent is removed by rotary evaporation, and purified by column chromatography to obtain a pale yellow oily liquid, which is the indoleacetic acid ester monomer.

4. The method for synthesizing an indoleacetic acid ester monomer as described in claim 3, characterized in that: The halogenated hydrocarbon solvent is one of dichloromethane, chloroform, carbon tetrachloride, or 1-bromopropane, and the ratio of the halogenated hydrocarbon solvent to indoleacetic acid is 10.00~25.00 mL: 1.00~2.50 g; the condensing agent is a carbodiimide dehydrating condensing agent, namely one of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, N,N-diisopropylcarbodiimide, or N,N-dicyclohexylcarbodiimide, and the mass of the condensing agent is 50%~110% of the mass of indoleacetic acid; the pyridine catalyst is one of pyridine, 3-methylpyridine, or 4-dimethylaminopyridine, and the mass of the pyridine catalyst is 5%~15% of the mass of indoleacetic acid; the acrylate reagent is one of hydroxyethyl acrylate / hydroxypropyl acrylate / hydroxybutyl acrylate or hydroxyethyl methacrylate / hydroxypropyl acrylate / hydroxybutyl acrylate, and the mass ratio of the acrylate reagent to indoleacetic acid is 1.00 g. ~ 3.00 g: 1.00 ~ 2.50 g.

5. The method for synthesizing a polymer antibacterial material as described in claim 2, characterized in that: This method involves first preparing a RAFT small molecule chain transfer agent, then adding the RAFT small molecule chain transfer agent, indole acetate monomer, oil-soluble initiator, and amide solvent to a Schlenk tube and magnetically stirring to ensure uniform mixing of the reaction substrate. Next, the sealed Schlenk tube is immersed in liquid nitrogen and subjected to several freeze-thaw cycles, with the final cycle involving filling the system with inert gas. The specific freeze-thaw process is as follows: after the solvent is completely frozen, the stopcock is opened to create a vacuum for 1-5 minutes; the reaction flask is then closed, and thawing continues until the solvent is completely thawed, repeating this process 2-5 times. The reaction is then stirred at 60-80 °C for 12-36 h. After the reaction is complete, the Schlenk tube is immersed in liquid nitrogen to quench the reaction. After thawing, the reaction mixture is dialyzed against deionized water for 1-4 days, and the product is collected and freeze-dried at -70 to -50 °C to obtain the precipitate, which is the polymer antibacterial material containing indole acetate monomer units.

6. The method for synthesizing a polymer antibacterial material as described in claim 5, characterized in that: The RAFT small molecule chain transfer agent is prepared by the following method: In a container equipped with a pre-cooling, stirring, and nitrogen protection device, n-dodecyl mercaptan is dissolved in a ketone solvent at 0-5 °C, and a phase transfer catalyst is added. The mixture is stirred magnetically until homogeneous. Subsequently, an alkaline aqueous solution is added dropwise, and stirring is continued for 15-30 min. Then, a carbon disulfide solution, a haloalkane reagent, and an aqueous solution of an alkaline reagent are added sequentially. After all substances have been added, the reaction is stirred under a nitrogen atmosphere for 12-36 h. After the reaction is completed, distilled water is added to quench the reaction and completely dissolve the precipitate in the solution. Then, an acidic solvent is added dropwise to adjust the pH of the solution to 2-6. The resulting mixed solution is vacuum filtered to obtain a precipitate. This precipitate is dissolved in an alcohol solvent, filtered, rotary evaporated, and pre-dried. The pre-dried solid is dissolved in a precipitant, and after partial precipitation, it is further cooled and crystallized at -20 to -5 °C. The solid product is obtained by vacuum filtration. This solid product is then subjected to 40-85 °C... After vacuum drying at ℃ to constant weight, a yellow solid is obtained, which is the RAFT small molecule chain transfer agent.

7. The method for synthesizing a polymer antibacterial material as described in claim 6, characterized in that: The ketone solvent is one of acetone, butanone, or cyclohexanone, and the mass ratio of the ketone solvent to n-dodecyl mercaptan is 50.00~65.00 g: 15.00~30.00 g; the phase transfer catalyst is one of hexadecyltrimethylammonium bromide, benzyltriethylammonium chloride, or methyltrioctylammonium chloride, and the mass of the phase transfer catalyst is 3.0%~8.0% of the mass of n-dodecyl mercaptan; both the alkaline aqueous solution and the aqueous solution of the alkaline reagent refer to aqueous solutions prepared with sodium hydroxide, potassium hydroxide, or triethylamine, with a mass concentration of 35%~55%; the mass ratio of the alkaline aqueous solution to n-dodecyl mercaptan is 5 g~20 g: 15.00~30.00 g; the mass ratio of the aqueous solution of the alkaline reagent to n-dodecyl mercaptan is 30.00~45.00 g: 15.00~30.00 g. g; the carbon disulfide solution refers to a solution with a concentration of 40.00% to 50.00% formed by dissolving carbon disulfide in a ketone solvent, wherein the mass of carbon disulfide is 20% to 40% of the mass of n-dodecyl mercaptan; the halogenated hydrocarbon solvent is one of dichloromethane, chloroform, carbon tetrachloride, or 1-bromopropane, wherein the mass of the halogenated hydrocarbon solvent is 75% to 90% of the mass of n-dodecyl mercaptan; the acid solvent is one of concentrated acid, concentrated nitric acid, or concentrated sulfuric acid; the alcohol solvent is one of anhydrous ethanol, isopropanol, or methanol, wherein the ratio of the alcohol solvent to n-dodecyl mercaptan is 100 to 250 mL: 15.00 to 30.00 g; the precipitant is one of n-hexane, n-octane, or petroleum ether, wherein the ratio of the precipitant to n-dodecyl mercaptan is 150 to 250 mL: 15.00 to 30.00 g.

8. The method for synthesizing a polymer antibacterial material as described in claim 5, characterized in that: The mass of the indoleacetic acid ester monomer is 2000% to 3500% of the mass of the RAFT small molecule chain transfer agent; the oil-soluble initiator is one of benzoyl peroxide, azobisisobutyronitrile, or azobisisoheptanenitrile, and the mass of the oil-soluble initiator is 1.0% to 5.0% of the mass of the RAFT small molecule chain transfer agent; the amide solvent is one of N-methylformamide, N,N-dimethylformamide, or N,N-dimethylacetamide, and the mass ratio of the amide solvent to the RAFT small molecule chain transfer agent is 5.00 to 20.00 g: 50 to 250 mg.

9. The method for synthesizing a polymer antibacterial material as described in claim 5, characterized in that: The inert gas refers to nitrogen or argon.

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