Aerogel-loaded thienyl conjugated polymer antibacterial agent as well as preparation method and application thereof

Abstract

The invention relates to the technical field of photocatalyst preparation, in particular to an aerogel-loaded thienyl conjugated polymer antibacterial agent as well as a preparation method and application thereof. The preparation method comprises the following steps: with 2, 5-bis (trimethyltin alkyl) thieno [3, 2-b] thiophene and carboxyl dibromide thiophene as raw materials, carrying out a coupling reaction in the presence of a catalyst and a solvent to obtain a carboxyl-modified thienyl conjugated polymer; the preparation method comprises the following steps: sequentially carrying out alkali treatment, oxidation treatment, freeze drying of straw cellulose sol and carbonization treatment on straw to obtain straw carbon aerogel; the straw carbon aerogel is soaked in a solution of the carboxyl modified thienyl conjugated polymer, and the aerogel loaded thienyl conjugated polymer antibacterial agent is obtained. The preparation method not only overcomes the defects that an existing aerogel composite material loaded polymer antibacterial agent is insufficient in light absorptivity, difficult to give full play to photocatalytic potential and poor in long-term use stability, but also solves the problem that an existing preparation method is high in cost.

Description

Technical Field

[0001] The present invention relates to the technical field of photocatalyst preparation, and in particular to an aerogel-loaded thiophene-based conjugated polymer antibacterial agent, a preparation method and application thereof. Background Art

[0002] Microbial contamination is a prominent root cause threatening global public health security. Although the development of antibiotics is an effective way to inhibit and kill pathogens, the excessive use of antibiotics can lead to significant drug resistance. Photocatalytic antibacterial technology, as a safer antibacterial method with no cytotoxicity or harmful effects, has received increasing attention. The antibacterial principle is that when photocatalytic materials are exposed to light, reactive oxygen species (ROS) are generated, which can destroy bacterial cell membranes, proteins and deoxyribonucleic acid (DNA).

[0003] Currently, antimicrobial materials are mainly divided into natural antimicrobial materials, composite antimicrobial materials, organic antimicrobial materials, and inorganic antimicrobial materials. Among them, organic photocatalysts avoid metal coordination chemistry, provide greater chemical stability, and show greater solubility in organic solvents. Polythiophene and its derivatives are considered promising photocatalytic candidates due to their unique electrical behavior, good environmental stability, low optical band gap, stability in doped or neutral states, and ease of synthesis.

[0004] Chinese patent CN118909301A discloses a high-temperature resistant polyimide aerogel composite material, its preparation method and application. On the basis of the chemical imidization-supercritical drying method, a metal oxide organic precursor or a non-metal oxide organic precursor is innovatively added as a reinforcing phase, and an effective and feasible aerogel and fiber preform unidirectional vacuum impregnation composite method is proposed for the first time, which is convenient for the modification and enhancement of polyimide aerogel. It has excellent high-temperature resistance, strong thermal stability, low density and high strength. Chinese patent CN117050372A discloses a high-performance thermal insulation material, specifically a shrinkage-resistant fiber-reinforced polyimide aerogel composite material. The fiber-reinforced PI aerogel composite material prepared therefrom has outstanding high-temperature resistance and high mechanical properties; and due to the reinforcement of the fiber, the shrinkage problem of the aerogel during the preparation process is greatly improved. Chinese patent CN108727818A discloses a silica / polyimide aerogel composite material, including hydrophobically modified silica aerogel and polyimide aerogel, which improves the mechanical strength of the composite thermal insulation material; the silica aerogel is a filler, which not only has a hydrophobic function, but also plays a thermal insulation role in the composite material by virtue of its superior thermal insulation performance, taking into account the advantages of high strength, high temperature resistance, low bulk density and low thermal conductivity, and good waterproof performance, meeting the performance requirements of thermal insulation materials in practical applications. Chinese patent CN113861682A discloses a preparation method and performance test of a low-density hydrophobic polyimide aerogel material with a greener and more convenient preparation process. It has the characteristics of hydrophobicity, adaptability to a variety of molding and casting processes, simple preparation process, and greatly reduces the volatilization of organic matter during the preparation process. The material is porous inside and has a density of less than 0.1g / cm 3 The water contact angle on the aerogel surface can reach over 120°, and it has good thermal properties. It has a wide range of applications in the fields of thermal insulation, catalysis, organic matter adsorption, and air filtration.

[0005] Currently, aerogel composites loaded with polymer antimicrobial agents produced by existing methods have a wide band gap, resulting in insufficient light absorption, making it difficult to fully realize their photocatalytic potential. Furthermore, their relatively high production costs limit their potential for large-scale application. Furthermore, existing aerogel composites loaded with polymer antimicrobial agents exhibit poor stability over long-term use, a drawback that severely hinders their practical application. Summary of the Invention

[0006] To address the shortcomings of the prior art, the present invention provides an aerogel-loaded thienyl conjugated polymer antimicrobial agent, its preparation method, and application. The present invention uses straw as a raw material, sequentially treating it with alkali and oxidation to obtain straw cellulose. The straw cellulose is then subjected to a sol-freeze drying method to obtain a porous straw cellulose aerogel, which is then carbonized to obtain a straw carbon aerogel. Finally, the straw carbon aerogel is impregnated with a solution of a carboxyl-modified thienyl conjugated polymer and dried to obtain an aerogel-loaded thienyl conjugated polymer antimicrobial agent. The present invention utilizes hydrogen bonding to load a carboxyl-modified thienyl conjugated polymer with a narrow band gap onto the porous structure of the straw carbon aerogel. This not only overcomes the problem of existing aerogel composite-loaded polymer antimicrobial agents with insufficient light absorption due to a wide band gap, making it difficult to fully realize their photocatalytic potential, but also addresses the high cost of existing preparation methods and the poor long-term stability of existing gel composite-loaded polymer antimicrobial agents. This results in a low-cost aerogel-loaded thienyl conjugated polymer antimicrobial agent with excellent photocatalytic performance and long-term stability.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] The first object of the present invention is to provide a method for preparing an aerogel-loaded thiophene-based conjugated polymer antibacterial agent, comprising the following steps:

[0009] S1. Using 2,5-bis(trimethylstannyl)thieno[3,2-b]thiophene and dibromocarboxythiophene as raw materials, a Stille coupling reaction is carried out in the presence of a catalyst and a solvent. During the coupling reaction, the trimethyltin group of 2,5-bis(trimethylstannyl)thiophene and the bromine atom of dibromocarboxythiophene undergo condensation reaction to obtain a carboxyl-modified thienyl conjugated polymer.

[0010] S2. The straw is mixed with a NaOH aqueous solution and subjected to alkali treatment to dissolve lignin and hemicellulose and expose cellulose, thereby obtaining alkali-treated straw.

[0011] S3. Under acidic conditions, the alkali-treated straw is placed in an aqueous solution of sodium hypochlorite for oxidation treatment to remove lignin and part of hemicellulose to obtain straw cellulose.

[0012] S4. First, the straw cellulose is dispersed in water to form a straw cellulose sol, which is then freeze-dried to obtain a porous straw cellulose aerogel. The porous straw cellulose aerogel is then carbonized to obtain a straw carbon aerogel.

[0013] S5. Immerse the straw carbon aerogel in a solution of a carboxyl-modified thienyl conjugated polymer. During the impregnation process, the carboxyl group of the carboxyl-modified thienyl conjugated polymer forms a hydrogen bond interaction with the hydroxyl group of the straw carbon aerogel and is loaded on the porous structure of the straw carbon aerogel. After drying, an aerogel-loaded thienyl conjugated polymer antibacterial agent is obtained.

[0014] Preferably, the mass ratio of the carboxyl-modified thienyl conjugated polymer to the straw carbon aerogel is 1:3-10.

[0015] Preferably, the mass ratio of 2,5-bis(trimethylstannyl)thieno[3,2-b]thiophene to dibromocarboxythiophene is 4 to 6:3.

[0016] Preferably, the dibrominated carboxythiophene is selected from 2,5-dibromo-3-carboxythiophene or 2,5-dibromo-3,4-dicarboxythiophene.

[0017] Preferably, when the dibrominated carboxythiophene is 2,5-dibromo-3-carboxythiophene, the obtained thiophene-based polymer is poly-2-(thieno[3,2-b]thiophene-2-yl)thiophene-3-carboxylic acid, abbreviated as NK-COOH; when the dibrominated carboxythiophene is 2,5-dibromo-3,4-dicarboxythiophene, the obtained thiophene-based polymer is poly-2-(thieno[3,2-b]thiophene-2-yl)thiophene-3,4-dicarboxylic acid, abbreviated as NK-(COOH)2.

[0018] Preferably, the solvent is deoxygenated anhydrous toluene and dehydrated and deoxygenated DMF.

[0019] Preferably, the mass ratio of straw to NaOH aqueous solution is 1:45-55, wherein the concentration of NaOH aqueous solution is 1 mol / L-2 mol / L.

[0020] Preferably, the acidic condition is provided by glacial acetic acid, and in the mixed aqueous solution of sodium hypochlorite and glacial acetic acid, the mass volume ratio of sodium hypochlorite, glacial acetic acid and water is 9g-11g:2mL-3mL:150mL.

[0021] Preferably, the conditions for the Stille coupling reaction are: under N2 protection, at 100°C to 120°C, with a stirring rate of 800 r / min, for 48h to 72h.

[0022] Preferably, the freeze-drying conditions are: freezing at -40°C to -18°C for 24 hours to 48 hours.

[0023] Preferably, the carbonization treatment conditions are: under N2 protection, raising the temperature to 460°C to 550°C at 5°C / min and maintaining for 1.5h to 3h.

[0024] Preferably, the immersion conditions are: stirring at 60° C. to 80° C. for 9 h to 12 h.

[0025] Preferably, the oxidation treatment conditions are: stirring the reaction at 60° C. to 100° C. for 2 h to 3 h.

[0026] Preferably, the drying conditions are: drying at 90° C. to 110° C. for 3 h to 4 h.

[0027] Preferably, the straw is cleaned and crushed before the alkali treatment to remove impurities and dust on the surface of the straw and reduce interference with subsequent reactions. At the same time, the specific surface area of the straw is increased by crushing so that it can be more fully contacted with the alkali solution during the alkali treatment process.

[0028] Preferably, in the solution of the carboxyl-modified thienyl conjugated polymer, the solvent is o-dichlorobenzene, and the carboxyl-modified thienyl conjugated polymer is slightly soluble in o-dichlorobenzene.

[0029] The second object of the present invention is to provide an aerogel-loaded thienyl conjugated polymer antibacterial agent prepared by the above preparation method.

[0030] The third object of the present invention is to provide the use of the above-mentioned aerogel-loaded thienyl conjugated polymer antibacterial agent in the preparation of a photocatalytic antibacterial agent, which can inhibit methicillin-resistant Staphylococcus aureus and Escherichia coli.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The present invention provides a method for preparing an aerogel-loaded thiophene-based conjugated polymer antibacterial agent. First, 2,5-bis(trimethylstannyl)thieno[3,2-b]thiophene and dibromocarboxylthiophene are used as raw materials, and a Stille coupling reaction is carried out in the presence of a catalyst and a solvent. The trimethyltin group of 2,5-bis(trimethylstannyl)thiophene and the bromine atom of dibromocarboxylthiophene undergo a condensation reaction to obtain a carboxyl-modified thiophene-based conjugated polymer. The straw is subjected to an alkali treatment and an oxidation treatment in sequence to obtain straw cellulose; the straw cellulose sol is first freeze-dried to obtain a porous straw cellulose aerogel, and the porous straw cellulose aerogel is then carbonized to obtain a straw carbon aerogel; the straw carbon aerogel is impregnated in a solution of a carboxyl-modified thienyl conjugated polymer, during which the carboxyl group of the carboxyl-modified thienyl conjugated polymer forms a hydrogen bond with the hydroxyl group of the straw carbon aerogel and is loaded on the porous structure of the straw carbon aerogel, and is dried to obtain an aerogel-loaded thienyl conjugated polymer antibacterial agent. The preparation method of the present invention not only overcomes the problem that the existing aerogel composite material-loaded polymer antibacterial agent has insufficient light absorption rate due to a wide band gap and is difficult to fully exert its photocatalytic potential, but also solves the high cost of the existing preparation method and the poor long-term stability of the existing gel composite material-loaded polymer antibacterial agent, thereby achieving a low-cost preparation of an aerogel-loaded thienyl conjugated polymer antibacterial agent with excellent photocatalytic performance and long-term stability.

[0033] The Stille coupling reaction is a one-step process with high yields and mild reaction conditions. Compared to other polymerization reactions involving complex steps and demanding conditions, the preparation method of the present invention is simple and efficient, offering significant cost advantages and a high performance-to-price ratio. Furthermore, the method utilizes agricultural waste straw as raw material, significantly reducing production costs.

[0034] In addition, the thienyl conjugated polymer with a conjugated structure used in the present invention is itself a star photocatalytic material with a narrow band gap (1eV to 3eV). In particular, the thienyl conjugated polymer in the present invention adopts a difused ring structure, which can further narrow its band gap, thereby significantly improving the photocatalytic performance of the material. In the aerogel-loaded thienyl conjugated polymer antibacterial agent of the present invention, a stable chemical bonding system is constructed through the hydrogen bond interaction formed between the carboxyl group of the carboxyl-modified thienyl conjugated polymer and the hydroxyl group of the straw carbon aerogel. This interaction not only enhances the structural stability of the antibacterial agent, but also effectively ensures its performance stability during long-term use.

[0035] 2. Compared with existing aerogel composite materials, hybrid aerogels and aerogel-loaded inorganic material photocatalytic antibacterial agents, the aerogel-loaded thienyl conjugated polymer antibacterial agent of the present invention has high light utilization efficiency, stable properties and can perform long-term and stable antibacterial activities multiple times, giving the aerogel-loaded thienyl conjugated polymer antibacterial agent an extremely high cost-effectiveness, enabling it to be applied to photocatalytic antibacterial in multiple fields and multiple occasions. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 These are SEM images of NK-COOH, CSCA, and CSCA-NK-COOH prepared in Example 1, where a is NK-COOH, b is CSCA, and c is CSCA-NK-COOH.

[0037] Figure 2 This is a graph showing the antibacterial efficiency of CSCA-NK-COOH prepared in Example 1 against MRSA under full-band LED cool white light irradiation and its 10-cycle stability.

[0038] Figure 3 This is a graph showing the antibacterial efficiency of CSCA-NK-COOH prepared in Example 1 against E. coli under full-band LED cold white light irradiation and its 8-cycle stability.

[0039] Figure 4 This is a graph showing the antibacterial efficiency of CSCA-NK-COOH prepared in Example 1 against MRSA under full-band LED cool white light irradiation for one month.

[0040] Figure 5 This is a graph showing the antibacterial efficiency of CSCA-NK-COOH prepared in Example 1 against E. coli under full-band LED cool white light irradiation for one month. DETAILED DESCRIPTION

[0041] The following will clearly and completely describe the technical solution of the present invention in conjunction with the data in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0042] It should be noted that the professional terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the following embodiments of the present invention can be purchased from the market or prepared by existing methods. Among them, the Tin reagent is 2,5-bis(trimethylstannyl)thieno[3,2-b]thiophene.

[0043] In the existing technology, although certain progress has been made in the research on antibacterial aerogel composite materials, how to effectively improve the photocatalytic antibacterial performance, reduce the preparation cost and enhance the long-term stability while ensuring their excellent thermal insulation, mechanical and other properties remains a key issue that needs to be solved urgently.

[0044] In response to the problems existing in the above-mentioned prior art, the present invention provides a method for preparing an aerogel-loaded thiophene-based conjugated polymer antibacterial agent, comprising the following steps: using 2,5-bis(trimethylstannyl)thieno[3,2-b]thiophene and dibromocarboxylthiophene as raw materials, carrying out a Stille coupling reaction in the presence of a catalyst and a solvent, and the trimethyltin group of 2,5-bis(trimethylstannyl)thiophene and the bromine atom of dibromocarboxylthiophene undergo a condensation reaction to obtain a carboxyl-modified thiophene-based conjugated polymer; impregnating straw carbon aerogel in a solution of the carboxyl-modified thiophene-based conjugated polymer, during the impregnation process, the carboxyl group of the carboxyl-modified thiophene-based conjugated polymer forms a hydrogen bond with the hydroxyl group of the straw carbon aerogel, and is loaded on the porous structure of the straw carbon aerogel, and is dried to obtain an aerogel-loaded thiophene-based conjugated polymer antibacterial agent.

[0045] To address the problem of aerogel composites loaded with polymer antimicrobial agents produced by existing preparation methods, which suffer from a wide band gap, resulting in insufficient light absorption and limited photocatalytic potential, the present invention utilizes a conjugated thienyl conjugated polymer, which itself possesses a narrow band gap (1eV to 3eV) and is a star photocatalytic structure. Furthermore, the thienyl conjugated polymer in the present invention utilizes a difused ring structure, further narrowing its band gap and significantly enhancing its photocatalytic performance.

[0046] To address the relatively high costs of existing methods for preparing aerogel composites loaded with polymer antimicrobial agents, which limits their large-scale application, the Stille coupling reaction employed in this invention is a one-step process with high yields and mild reaction conditions. Compared to other polymerization reactions involving complex steps and demanding conditions, this method offers significant cost advantages and a high performance-to-price ratio.

[0047] To address the problem of poor long-term stability of existing gel composite-loaded polymer antimicrobial agents, which seriously hinders their practical application, the aerogel-loaded thienyl conjugated polymer antimicrobial agent prepared by the present invention comprises a carboxyl-modified thienyl conjugated polymer containing carboxyl groups, while the straw-carbon aerogel contains hydroxyl groups. During the impregnation process, the carboxyl groups of the carboxyl-modified thienyl conjugated polymer form hydrogen bonds with the hydroxyl groups of the straw-carbon aerogel, thereby ensuring the long-term stability of the aerogel-loaded thienyl conjugated polymer antimicrobial agent.

[0048] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments:

[0049] Example 1

[0050] A method for preparing an aerogel-loaded thiophene-based conjugated polymer antibacterial agent comprises the following steps:

[0051] S1. Under nitrogen protection, 120 mg of Tin reagent, 90 mg of 2,5-dibromo-3-carboxythiophene, 30 mg of tetrakis(triphenylphosphine)palladium, 40 mL of dehydrated and deoxygenated toluene and 8 mL of DMF were added to a double-necked flask, and stirred at 100°C at a stirring rate of 800 r / min for 48 hours. After the reaction was completed, it was naturally cooled to room temperature and transferred to an eggplant-shaped flask for rotary evaporation. Subsequently, ethanol was added to the residual concentrated solution for precipitation, and then filtered to obtain a solid; then, ethanol and acetone were used to Soxhlet remove impurities from the solid in turn, and after drying, a monocarboxyl-modified thienyl conjugated polymer was obtained, which was recorded as NK-COOH.

[0052] S2. First, the corn stalks were cut into small pieces, washed with deionized water, dried and crushed to obtain stalk powder; then, the stalk powder and 1 mol / L NaOH aqueous solution were mixed at a mass ratio of 1:50, and stirred at 80°C for 3 hours. After the stirring reaction, the stalks were washed with deionized water until neutral to obtain alkali-treated stalks; finally, the alkali-treated stalks were immersed in 150 mL of an aqueous solution containing 10 g of sodium hypochlorite and 2.5 mL of glacial acetic acid, stirred at 80°C for 3 hours, washed with deionized water, placed in an oven, and dried at 80°C for 4 hours to obtain stalk cellulose.

[0053] S3. First, the straw cellulose was dispersed in 200 mL of deionized water and ultrasonically treated for 30 min to form a uniform sol to obtain a straw cellulose sol; then, the straw cellulose sol was poured into a beaker, placed in a refrigerator and frozen at -18°C for 24 h, and then freeze-dried for 48 h to obtain a porous straw cellulose aerogel; finally, the porous straw cellulose aerogel was placed in a corundum crucible, and nitrogen was introduced into a tubular furnace at a flow rate of 80 mL / min for protection, and the temperature was raised to 500°C at a heating rate of 5°C / min and maintained for 2 h to obtain a straw carbon aerogel, which was recorded as CSCA.

[0054] S4. Add 2 mg of NK-COOH to o-dichlorobenzene and ultrasonicate for 0.5 h. After heating to 60°C, immerse 10 mg of CSCA and stir for 9 h. After filtering, apply it on a glass plate and dry it at 100°C for 3 h to obtain an aerogel-loaded thienyl conjugated polymer antibacterial agent, which is recorded as CSCA-NK-COOH.

[0055] Example 2

[0056] A method for preparing an aerogel-loaded thiophene-based conjugated polymer antibacterial agent, which has the same preparation steps as Example 1, except that the 2,5-dibromo-3-carboxythiophene in S1 is replaced with 2,5-dibromo-3,4-dicarboxythiophene, comprising the following steps:

[0057] S1. Under nitrogen protection, 120 mg of Tin reagent, 90 mg of 2,5-dibromo-3-carboxythiophene, 30 mg of tetrakis(triphenylphosphine)palladium, 40 mL of dehydrated and deoxygenated toluene and 8 mL of DMF were added to a double-necked flask, and stirred at 100°C at a stirring rate of 800 r / min for 48 hours. After the reaction was completed, it was naturally cooled to room temperature and transferred to an eggplant-shaped flask for rotary evaporation. Subsequently, ethanol was added to the residual concentrated solution for precipitation, and then filtered to obtain a solid; then, ethanol and acetone were used to Soxhlet remove impurities from the solid in turn, and after drying, a monocarboxyl-modified thienyl conjugated polymer was obtained, which was recorded as NK-(COOH)2.

[0058] S2. First, the corn stalks were cut into small pieces, washed with deionized water, dried and crushed to obtain stalk powder; then, the stalk powder and 1 mol / L NaOH aqueous solution were mixed at a mass ratio of 1:50, and stirred at 80°C for 3 hours. After the stirring reaction, the stalks were washed with deionized water until neutral to obtain alkali-treated stalks; finally, the alkali-treated stalks were immersed in 150 mL of an aqueous solution containing 10 g of sodium hypochlorite and 2.5 mL of glacial acetic acid, stirred at 80°C for 3 hours, washed with deionized water, placed in an oven, and dried at 80°C for 4 hours to obtain stalk cellulose.

[0059] S3. First, the straw cellulose was dispersed in 200 mL of deionized water and ultrasonically treated for 30 min to form a uniform sol to obtain a straw cellulose sol; then, the straw cellulose sol was poured into a beaker, placed in a refrigerator and frozen at -18°C for 24 h, and then freeze-dried for 48 h to obtain a porous straw cellulose aerogel; finally, the porous straw cellulose aerogel was placed in a corundum crucible, and nitrogen was introduced into a tubular furnace at a flow rate of 80 mL / min for protection, and the temperature was raised to 500°C at a heating rate of 5°C / min and maintained for 2 h to obtain a straw carbon aerogel, which was recorded as CSCA.

[0060] S4. Add 2 mg of NK-(COOH)2 to o-dichlorobenzene and ultrasonicate for 0.5 h. After heating to 60 °C, immerse 10 mg of CSCA and stir for 9 h. After filtering, apply it on a glass plate and dry it at 100 °C for 3 h to obtain an aerogel-loaded thienyl conjugated polymer antibacterial agent, which is recorded as CSCA-NK-COOH.

[0061] Example 3

[0062] A method for preparing an aerogel-loaded thiophene-based conjugated polymer antibacterial agent comprises the following steps:

[0063] S1. Under nitrogen protection, 180 mg of Tin reagent, 90 mg of 2,5-dibromo-3-carboxythiophene, 30 mg of tetrakis(triphenylphosphine)palladium, 40 mL of dehydrated and deoxygenated toluene and 8 mL of DMF were added to a double-necked flask, and stirred at 120°C at a stirring rate of 800 r / min for 72 hours. After the reaction was completed, it was naturally cooled to room temperature and transferred to an eggplant-shaped flask for rotary evaporation. Subsequently, ethanol was added to the residual concentrated solution for precipitation, and then filtered to obtain a solid; then, ethanol and acetone were used to Soxhlet remove impurities from the solid in turn, and after drying, a monocarboxyl-modified thienyl conjugated polymer was obtained, which was recorded as NK-COOH.

[0064] S2. First, the corn stalks were cut into small pieces, washed with deionized water, dried and crushed to obtain straw powder; then, the straw powder was mixed with a 2 mol / L NaOH aqueous solution at a mass ratio of 1:45, and stirred at a constant speed at 80°C for 3 h. After the stirring reaction, the straw was washed with deionized water until neutral to obtain alkali-treated straw; finally, the alkali-treated straw was immersed in 150 mL of an aqueous solution containing 9 g of sodium hypochlorite and 2 mL of glacial acetic acid, stirred at 60°C for 3 h, washed with deionized water, placed in an oven, and dried at 80°C for 4 h to obtain straw cellulose.

[0065] S3. First, the straw cellulose was dispersed in 200 mL of deionized water and ultrasonically treated for 30 min to form a uniform sol to obtain a straw cellulose sol; then, the straw cellulose sol was poured into a beaker, placed in a refrigerator and frozen at -18°C for 48 h, and then freeze-dried for 48 h to obtain a porous straw cellulose aerogel; finally, the porous straw cellulose aerogel was placed in a corundum crucible, and nitrogen was introduced into a tubular furnace at a flow rate of 80 mL / min for protection, and the temperature was raised to 460°C at a heating rate of 5°C / min and maintained for 3 h to obtain a straw carbon aerogel, which was recorded as CSCA.

[0066] S4. Add 1 mg of NK-COOH to o-dichlorobenzene and ultrasonicate for 0.5 h. After heating to 60 °C, immerse 10 mg of CSCA and stir for 9 h. After filtering, apply it on a glass plate and dry it at 90 °C for 4 h to obtain an aerogel-loaded thienyl conjugated polymer antibacterial agent, which is recorded as CSCA-NK-COOH.

[0067] Example 4

[0068] A method for preparing an aerogel-loaded thiophene-based conjugated polymer antibacterial agent comprises the following steps:

[0069] S1. Under nitrogen protection, 120 mg of Tin reagent, 90 mg of 2,5-dibromo-3-carboxythiophene, 30 mg of tetrakis(triphenylphosphine)palladium, 40 mL of dehydrated and deoxygenated toluene and 8 mL of DMF were added to a double-necked flask, and stirred at 120°C at a stirring rate of 800 r / min for 48 hours. After the reaction was completed, it was naturally cooled to room temperature and transferred to an eggplant-shaped flask for rotary evaporation. Subsequently, ethanol was added to the residual concentrated solution for precipitation, and then filtered to obtain a solid; then, ethanol and acetone were used to Soxhlet remove impurities from the solid in turn, and after drying, a monocarboxyl-modified thienyl conjugated polymer was obtained, which was recorded as NK-COOH.

[0070] S2. First, the corn stalks were cut into small pieces, washed with deionized water, dried and crushed to obtain straw powder; then, the straw powder was mixed with a 1 mol / L NaOH aqueous solution at a mass ratio of 1:55, and stirred at a constant speed at 80°C for 3 h. After the stirring reaction, the mixture was washed with deionized water until neutral to obtain alkali-treated straw; finally, the alkali-treated straw was immersed in 150 mL of an aqueous solution containing 11 g of sodium hypochlorite and 3 mL of glacial acetic acid, stirred at 100°C for 2 h, washed with deionized water, placed in an oven, and dried at 80°C for 4 h to obtain straw cellulose.

[0071] S3. First, the straw cellulose was dispersed in 200 mL of deionized water and ultrasonically treated for 30 min to form a uniform sol to obtain a straw cellulose sol; then, the straw cellulose sol was poured into a beaker, placed in a refrigerator and frozen at -40 ° C for 48 h, and then freeze-dried for 48 h to obtain a porous straw cellulose aerogel; finally, the porous straw cellulose aerogel was placed in a corundum crucible, and nitrogen was introduced into a tubular furnace at a flow rate of 80 mL / min for protection, and the temperature was increased to 550 ° C at a rate of 5 ° C / min and maintained for 1.5 h to obtain a straw carbon aerogel, which was recorded as CSCA.

[0072] S4. Add 3 mg of NK-COOH to o-dichlorobenzene and sonicate for 0.5 h. Heat to 80 °C and immerse 10 mg of CSCA in it and stir for 12 h. After filtering, apply it on a glass plate and dry it at 110 °C for 3 h to obtain an aerogel-loaded thienyl conjugated polymer antibacterial agent, which is recorded as CSCA-NK-COOH.

[0073] Comparative Example 1

[0074] A method for preparing an aerogel-loaded thiophene-based conjugated polymer antibacterial agent comprises the following steps:

[0075] S1. Under nitrogen protection, 120 mg of Tin reagent, 90 mg of 2,5-dibromo-3-carboxythiophene, 30 mg of tetrakis(triphenylphosphine)palladium, 40 mL of dehydrated and deoxygenated toluene and 8 mL of DMF were added to a double-necked flask, and stirred at 100°C at a stirring rate of 800 r / min for 48 hours. After the reaction was completed, it was naturally cooled to room temperature and transferred to an eggplant-shaped flask for rotary evaporation. Subsequently, ethanol was added to the residual concentrated solution for precipitation, and then filtered to obtain a solid; then, ethanol and acetone were used to Soxhlet remove impurities from the solid in turn, and after drying, a monocarboxyl-modified thienyl conjugated polymer was obtained, which was recorded as NK-COOH.

[0076] S2. First, the corn stalks were cut into small pieces, washed with deionized water, dried and crushed to obtain stalk powder; then, the stalk powder and 1 mol / L NaOH aqueous solution were mixed at a mass ratio of 1:50, and stirred at 80°C for 3 hours. After the stirring reaction, the stalks were washed with deionized water until neutral to obtain alkali-treated stalks; finally, the alkali-treated stalks were immersed in 150 mL of an aqueous solution containing 10 g of sodium hypochlorite and 2.5 mL of glacial acetic acid, stirred at 80°C for 3 hours, washed with deionized water, placed in an oven, and dried at 80°C for 4 hours to obtain stalk cellulose.

[0077] S3. First, the straw cellulose was dispersed in 200 mL of deionized water and ultrasonically treated for 30 min to form a uniform sol to obtain a straw cellulose sol; then, the straw cellulose sol was poured into a beaker, placed in a refrigerator and frozen at -18°C for 24 h, and then freeze-dried for 48 h to obtain a porous straw cellulose aerogel, which was recorded as CSFA.

[0078] S4. Add 2 mg of NK-COOH to o-dichlorobenzene and ultrasonicate for 0.5 h. After heating to 60°C, immerse 10 mg of CSFA and stir for 9 h. After filtering, apply it on a glass plate and dry it at 100°C for 3 h to obtain an aerogel-loaded thienyl conjugated polymer antibacterial agent, which is recorded as CSFA-NK-COOH.

[0079] Comparative Example 2

[0080] A method for preparing an aerogel-loaded thiophene-based conjugated polymer antibacterial agent, which has the same preparation steps as Example 2, except that the 2,5-dibromo-3-carboxythiophene in S1 is replaced with 2,5-dibromo-3,4-dicarboxythiophene, comprises the following steps:

[0081] S1. Under nitrogen protection, 120 mg of Tin reagent, 90 mg of 2,5-dibromo-3-carboxythiophene, 30 mg of tetrakis(triphenylphosphine)palladium, 40 mL of dehydrated and deoxygenated toluene and 8 mL of DMF were added to a double-necked flask, and stirred at 100°C at a stirring rate of 800 r / min for 48 hours. After the reaction was completed, it was naturally cooled to room temperature and transferred to an eggplant-shaped flask for rotary evaporation. Subsequently, ethanol was added to the residual concentrated solution for precipitation, and then filtered to obtain a solid; then, ethanol and acetone were used to Soxhlet remove impurities from the solid in turn, and after drying, a monocarboxyl-modified thienyl conjugated polymer was obtained, which was recorded as NK-COOH.

[0082] S2. First, the corn stalks were cut into small pieces, washed with deionized water, dried and crushed to obtain straw powder; then, the straw powder was mixed with a 1 mol / L NaOH aqueous solution at a mass ratio of 1:50, and the mixture was stirred at a constant speed at 80°C for 3 h. After the stirring reaction, the mixture was washed with deionized water until neutral to obtain alkali-treated straw; finally, the alkali-treated straw was immersed in 150 mL of an aqueous solution containing 10 g of sodium hypochlorite and 2.5 mL of glacial acetic acid, stirred at 80°C for 3 h, washed with deionized water, placed in an oven, and dried at 80°C for 4 h to obtain straw cellulose.

[0083] S3. First, the straw cellulose was dispersed in 200 mL of deionized water and ultrasonically treated for 30 min to form a uniform sol to obtain a straw cellulose sol; then, the straw cellulose sol was poured into a beaker, placed in a refrigerator and frozen at -18°C for 24 h, and then freeze-dried for 48 h to obtain a porous straw cellulose aerogel, which was recorded as CSFA.

[0084] S4. Add 2 mg of NK-COOH to o-dichlorobenzene and ultrasonicate for 0.5 h. After heating to 60°C, immerse 10 mg of CSFA and stir for 9 h. After filtering, apply it on a glass plate and dry it at 100°C for 3 h to obtain an aerogel-loaded thienyl conjugated polymer antibacterial agent, which is recorded as CSFA-NK-COOH.

[0085] The aerogel-loaded thiophene-based conjugated polymer antibacterial agent of Examples 1 to 2 and Comparative Examples 1 to 2 was subjected to a photocatalytic antibacterial test. The test conditions were a full-band LED cold white light source with a light intensity of 150 mW / cm 2 .

[0086] The specific operation steps are as follows: Methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli (E. coli) were cultured in a sterile condition at 37°C for 18 h, centrifuged to remove metabolites, and then diluted with 0.01 mol / L PBS, pH 7.4, to obtain approximately 10 7cfu of bacterial suspension.

[0087] The bacterial suspension was controlled at 20 mL, and 2 mg and 0.1 mg / mL of the aerogel-loaded thienyl conjugated polymer antimicrobial agent from Examples 1 and 2 and Comparative Examples 1 and 2 were added, respectively. The desired LED white light was then adjusted for irradiation. Samples were taken at designated time intervals of 0, 20 min, 40 min, 60 min, 80 min, 100 min, 120 min, and 140 min. The reaction solution was gradiently diluted with PBS solution, and 100 μL of the final diluted bacterial suspension was plated onto a freshly prepared TSA plate. The plate was incubated in an incubator at 37°C ± 0.5°C for 16 h, and the colonies were counted and photographed.

[0088] The cyclic test involved centrifuging the reaction mixture, sterilizing it at high temperature, washing it three times with deionized water, and then drying it. The mixture was then re-tested in the antibacterial experiment under the same experimental conditions. For the antibacterial efficiency test one month later, the prepared material was subjected to one photocatalytic antibacterial test, then centrifuged, sterilized, washed, and dried for later use. After storage for one month, the material was re-tested in the photocatalytic sterilization reaction system under the same experimental conditions. The results are shown in Table 1.

[0089] Table 1 Bactericidal time, inhibition rate and cyclic stability of aerogel-loaded thiophene-based conjugated polymer antibacterial agents for MRSA and E. coli in Examples 1 to 2 and Comparative Examples 1 to 2

[0090]

[0091]

[0092] From the results in Table 1, it can be seen that Example 1 has the best antibacterial effect and the best cyclic stability. After 40 minutes of visible light irradiation, the killing rate of methicillin-resistant Staphylococcus aureus (MRSA) is close to 100%, and the antibacterial effect can be basically unchanged after 10 cycles; after 120 minutes of visible light irradiation, the killing rate of Escherichia coli (E. coli) exceeds 90%, and the antibacterial effect can be tested 8 times and is still above 85%. In addition, the photocatalytic antibacterial efficiency of the aerogel-loaded thienyl conjugated polymer antibacterial agent of Example 1 can still be maintained at a high sterilization rate level after one month. After 40 minutes of visible light irradiation, the killing rate of methicillin-resistant Staphylococcus aureus (MRSA) is as high as 86%; after 120 minutes of visible light irradiation, the killing rate of Escherichia coli (E. coli) is about 80%.

[0093] observe Figure 1It was concluded that the monocarboxylthiophene-based conjugated polymer NK-COOH particles prepared in Example 1 were successfully loaded on the straw carbon aerogel CSCA, thereby constructing CSCA-NK-COOH.

[0094] observe Figure 2 The results showed that the CSCA-NK-COOH prepared in Example 1 had the best antibacterial effect and the best cyclic stability. After 40 minutes of visible light irradiation, the killing rate against methicillin-resistant Staphylococcus aureus was close to 100%, and the antibacterial effect showed little significant decline after 10 cycles.

[0095] observe Figure 3 It was found that the CSCA-NK-COOH prepared in Example 1 had a killing rate of over 90% against Escherichia coli after 120 minutes of visible light irradiation, and the antibacterial effect was still above 85% after 8 cycles of testing.

[0096] observe Figure 4 The antibacterial properties of CSCA-NK-COOH prepared in Example 1 demonstrated excellent long-term stability. Specifically, after a one-month storage period, the aerogel-loaded thienyl conjugated polymer antimicrobial agent maintained a high kill rate with no significant degradation. After 40 minutes of visible light irradiation, CSCA-NK-COOH achieved an 86% kill rate against methicillin-resistant Staphylococcus aureus (MRSA), demonstrating the high efficacy and durability of the aerogel-loaded thienyl conjugated polymer antimicrobial agent in antimicrobial applications.

[0097] observe Figure 5 The long-term stability of the antibacterial properties of CSCA-NK-COOH prepared in Example 1 was particularly outstanding. After a one-month storage period, the photocatalytic antibacterial efficiency of the aerogel-loaded thiophene-based conjugated polymer antibacterial agent remained stable at a high kill rate, with no significant performance degradation. Under continuous visible light irradiation for 120 minutes, CSCA-NK-COOH achieved an approximately 80% kill rate against E. coli, further demonstrating the material's high efficacy and long-term effectiveness in antibacterial applications.

[0098] It should be noted that when the present invention involves numerical ranges, it should be understood that both endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as those in the embodiments, in order to avoid redundancy, the present invention describes preferred embodiments. Although preferred embodiments of the present invention have been described, those skilled in the art will be able to make additional changes and modifications to these embodiments once they understand the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0099] It is obvious that those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications of the present invention fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for preparing an aerogel-loaded thiophene-based conjugated polymer antibacterial agent, characterized in that: The following steps are involved: Using 2,5-bis(trimethylstannyl)thieno[3,2-b]thiophene and dibromocarboxythiophene as raw materials, a Stille coupling reaction is carried out in the presence of a catalyst and a solvent. The trimethyltin group of 2,5-bis(trimethylstannyl)thiophene and the bromine atom of dibromocarboxythiophene undergo a condensation reaction to obtain a carboxyl-modified thienyl conjugated polymer. The straw carbon aerogel is immersed in a solution of carboxyl-modified thienyl conjugated polymer. During the impregnation process, the carboxyl group of the carboxyl-modified thienyl conjugated polymer forms hydrogen bonds with the hydroxyl group of the straw carbon aerogel and is loaded on the porous structure of the straw carbon aerogel. After drying, an aerogel-loaded thienyl conjugated polymer antibacterial agent is obtained.

2. The method for preparing the aerogel-loaded thienyl conjugated polymer antibacterial agent according to claim 1, characterized in that: The mass ratio of the carboxyl-modified thienyl conjugated polymer to the straw carbon aerogel is 1:3-10.

3. The method for preparing the aerogel-loaded thienyl conjugated polymer antibacterial agent according to claim 1, characterized in that: The mass ratio of 2,5-bis(trimethylstannyl)thieno[3,2-b]thiophene to dibromocarboxythiophene is 4-6:

3.

4. The method for preparing the aerogel-loaded thienyl conjugated polymer antibacterial agent according to claim 3, characterized in that: The dibrominated carboxythiophene is selected from 2,5-dibromo-3-carboxythiophene or 2,5-dibromo-3,4-dicarboxythiophene.

5. The method for preparing the aerogel-loaded thienyl conjugated polymer antibacterial agent according to claim 1, characterized in that: The immersion conditions are: stirring at 60°C to 80°C for 9h to 12h.

6. The method for preparing the aerogel-loaded thienyl conjugated polymer antibacterial agent according to claim 1, characterized in that: The conditions for the Stille coupling reaction are: under N2 protection, stirring the reaction at 100°C to 120°C for 48h to 72h.

7. The method for preparing the aerogel-loaded thienyl conjugated polymer antibacterial agent according to claim 1, characterized in that: Straw carbon aerogel was prepared according to the following steps: The straw is first subjected to an alkali treatment and then to an oxidation treatment to remove lignin and part of hemicellulose and expose cellulose to obtain straw cellulose, and the straw cellulose is dispersed in water to obtain a straw cellulose sol; The straw cellulose sol is first freeze-dried to obtain porous straw cellulose aerogel, and then the porous straw cellulose aerogel is carbonized to obtain straw carbon aerogel.

8. The method for preparing the aerogel-loaded thienyl conjugated polymer antibacterial agent according to claim 7, characterized in that: The carbonization treatment conditions are: under N2 protection, increase the temperature to 460°C~550°C at 5°C / min and maintain for 1.5h~3h.

9. An aerogel-loaded thienyl conjugated polymer antibacterial agent prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the aerogel-loaded thienyl conjugated polymer antibacterial agent according to claim 9 in the preparation of a photocatalytic antibacterial agent, characterized in that: The photocatalytic antibacterial agent can inhibit methicillin-resistant Staphylococcus aureus and Escherichia coli.

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