An antibacterial polymer nanocomposite and a method for preparing the same

Abstract

The present application relates to the technical field of polymer preparation, in particular to an antibacterial polymer nanocomposite material and a preparation method thereof.The material takes polyhydroxybutyrate and polybutylene adipate terephthalate as a matrix, fuses a non-metallic organic framework antibacterial agent, a non-peptide antibacterial mimic and a photothermal response nanomaterial, wherein the non-metallic organic framework antibacterial agent and the non-peptide mimic synergistically play a chemical sterilization role, and the photothermal response nanomaterial improves the sterilization efficiency through physical thermal effect, so that the material provided by the present application can realize broad-spectrum, efficient and persistent antibacterial effect through the organic combination of multiple antibacterial mechanisms.The material provides a high-efficiency antibacterial solution of multiple mechanism synergy in view of the defects of single antibacterial mechanism and non-persistent effect of traditional materials, and is suitable for medical and packaging fields, and has significant economic value and application prospect.

Description

Technical Field

[0001] This invention relates to the field of polymer preparation technology, specifically to an antibacterial polymer nanocomposite material and its preparation method. Background Technology

[0002] Currently, bacterial infections have become a global public health challenge, especially with the emergence of drug-resistant strains, highlighting the limitations of traditional antibacterial materials. Existing antibacterial materials, such as composites containing silver, zinc, and other metal nanoparticles, while widely used in medical devices and food packaging, still have many shortcomings. First, their antibacterial mechanisms are singular, primarily relying on the slow release of metal ions or physical contact sterilization, which easily leads to adaptive drug resistance in bacteria. For example, silver-based antibacterial agents work by interfering with bacterial enzyme systems, but drug-resistant bacteria can rapidly evolve tolerance through efflux pumps or gene mutations. Simultaneously, the release rate of metal ions is difficult to precisely control; continuous release in non-infectious environments not only wastes active ingredients but may also promote increased bacterial resistance. Second, biosafety and environmental risks cannot be ignored. Accumulation of metal nanoparticles in vivo may induce cytotoxicity, and excessive silver ion intake can even lead to organ damage and metabolic disorders. Furthermore, the environmental leaching of metal ions has significant toxic effects on aquatic organisms, causing ecological damage. Third, the stability and durability of these materials are insufficient. Traditional antibacterial agents are easily deactivated by environmental factors (such as pH and temperature), and nanoparticles tend to aggregate in polymer matrices, leading to uneven distribution and reduced antibacterial efficiency. For example, inorganic nanoparticles such as titanium dioxide have poor dispersibility, requiring high addition levels (typically >5%) to maintain antibacterial effects, which in turn causes a decline in mechanical properties. Finally, processing compatibility and functional synergy are poor. Most antibacterial materials struggle to achieve a balance between antibacterial performance and material mechanical properties. Simple blending of nanofillers easily generates interfacial defects, increasing material brittleness; while complex multilayer structures can improve performance, their complex processes and high costs make large-scale production difficult. Furthermore, the lack of synergistic design among different antibacterial components prevents the coupling of multiple bactericidal pathways, limiting further improvements in antibacterial efficiency.

[0003] In summary, developing a novel antibacterial polymer nanocomposite material that combines multiple synergistic antibacterial mechanisms, controlled release, biocompatibility, and good processing performance has become an urgent need to address the shortcomings of existing technologies. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, the present invention aims to provide an antibacterial polymer nanocomposite material and its preparation method. This material uses polyhydroxybutyrate (PHB) and polybutylene adipate-terephthalate (PAT) as a matrix, incorporating a non-metallic organic framework antibacterial agent, a non-peptide antibacterial mimic, and photothermal responsive nanomaterials. The PHB and PAT synergistically exert chemical bactericidal effects, while the photothermal responsive nanomaterials enhance bactericidal efficiency through physical thermal effects. Thus, the material provided by this invention achieves broad-spectrum, highly efficient, and long-lasting antibacterial effects through the organic combination of multiple antibacterial mechanisms. This material addresses the shortcomings of traditional materials, such as single antibacterial mechanisms and short-lasting effects, providing a highly efficient antibacterial solution with multi-mechanism synergy. It is suitable for the medical and packaging fields and has significant economic value and application prospects.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] An antibacterial polymer nanocomposite material comprises the following components by weight: 40-50 parts polyhydroxybutyrate, 20-30 parts polybutylene adipate terephthalate, 4-7 parts non-metallic organic framework antibacterial agent, 5-9 parts non-peptide antibacterial mimic, 3-6 parts photothermal responsive nanomaterials, 3-5 parts interface compatibilizer, and 2-4 parts toughening agent;

[0007] The non-metallic organic framework antibacterial agent is prepared through the following steps:

[0008] Tetra(4-aminophenyl)porphyrin and dimethylacetamide were dissolved in a mixed solvent of mesitylene and 1,4-dioxane at a molar ratio of 1-2:2-4, and acetic acid at a concentration of 3-6M was added as a catalyst. The reaction was carried out at 100-120℃ for 72-80 h. The purple precipitate was collected by centrifugation, washed, and dried to obtain the non-metallic organic framework antibacterial agent.

[0009] The non-peptide antimicrobial mimicry is prepared by the following steps:

[0010] S11. Dissolve monomethoxy polyethylene glycol and cholic acid in anhydrous dichloromethane at a molar ratio of 1-2:2-4, and stir until a homogeneous solution is formed;

[0011] S12. Add N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine to the above solution, and stir the reaction at room temperature for 12-24 h under nitrogen protection. After the reaction is completed, filter to remove the byproduct dicyclohexylurea, precipitate the filtrate with ice-cold ether, collect the precipitate by centrifugation, wash it with cold ether 3-4 times, and dry it to obtain the cholic acid-polyethylene glycol copolymer.

[0012] S13. Dissolve the cholic acid-polyethylene glycol copolymer in anhydrous N,N-dimethylformamide, add iodomethane and potassium carbonate, and react at 60-80°C for 6-8 hours to quaternize all hydroxyl groups on the cholic acid backbone. After the reaction is complete, drop the solution into anhydrous diethyl ether to precipitate, collect the product by centrifugation, wash with diethyl ether 3-4 times, and dry to obtain the non-peptide antibacterial mimic.

[0013] The photothermal responsive nanomaterial is prepared through the following steps:

[0014] S21. Place the vanadium powder in an air atmosphere and heat-treat it at 350-400℃ for 2-3 hours to allow its surface to oxidize naturally and form a layer of vanadium oxide.

[0015] S22. Disperse the heat-treated vanadium powder in N-methylpyrrolidone at a concentration of 1-3 mg / mL, sonicate it in an ice bath at 0-3℃ for 4-6 h under argon protection using a probe sonicator, then centrifuge for 10-15 min to remove the unpeeled thick-layer particles, wash with ethanol and water alternately 3-4 times, and then vacuum dry at 60-80℃ to constant weight to obtain the photothermal responsive nanomaterial.

[0016] Preferably, in the mixed solvent, the volume ratio of tricresylbenzene to 1,4-dioxane is 1-2:1-2.

[0017] Preferably, the amount of acetic acid added accounts for 1-2% of the total liquid volume of the mixed solvent.

[0018] Preferably, in step S12, the molar ratio of N,N'-dicyclohexylcarbodiimide to cholic acid is 1:1.1-1.3; and the molar ratio of 4-dimethylaminopyridine to cholic acid is 1:0.1-0.2.

[0019] In step S13, the molar ratio of iodomethane to bile acid is 1:5-6; the molar ratio of potassium carbonate to bile acid is 1:0.5-0.6.

[0020] Preferably, the interface compatibilizer is further defined as a maleic anhydride-grafted interface compatibilizer; and the toughening agent is further defined as a polyolefin elastomer-type toughening agent.

[0021] A method for preparing an antibacterial polymer nanocomposite material, comprising the following steps:

[0022] S1. Solution blending and pre-dispersion:

[0023] S101. Take half a part by weight of polyhydroxybutyrate and polybutylene adipate-terephthalate respectively, dissolve them in chloroform, and mechanically stir in a water bath at 60-80℃ to prepare a polymer solution with a total concentration of 5-7 wt%.

[0024] S102. Mix the non-metallic organic framework antibacterial agent, non-peptide antibacterial mimic, and photothermal responsive nanomaterials according to the mass ratio and add them to chloroform. Perform preliminary dispersion in an ice-water bath at 0-4℃ to obtain a nano slurry.

[0025] S103. The nano-slurry is added dropwise to the polymer solution, and ultrasonically treated at 40-50℃ for 1-2 hours while stirring, so that the nanoparticles are fully deagglomerated and uniformly dispersed.

[0026] S104. The uniformly dispersed solution obtained in step S103 is poured into a disc container and left to stand for 24-48 hours. Then it is dried at 40-50℃ for 24-48 hours to completely remove the residual solvent. The dried blend is then crushed into fine particles using a pulverizer to obtain a pre-dispersed composite masterbatch.

[0027] S2. Melt blending granulation:

[0028] S201. Add the pre-dispersed masterbatch, the remaining polyhydroxybutyrate, the remaining polybutylene adipate terephthalate, the interface compatibilizer, and the toughening agent to a high-speed mixer and mix for 5-10 minutes to make the components initially uniformly mixed.

[0029] S202. The premixed material is added to a twin-screw extruder for extrusion. The extrudate is water-cooled, air-dried, and granulated by a pelletizer. After drying, it is hot-pressed to obtain the antibacterial polymer nanocomposite material.

[0030] Preferably, in step S202, the temperatures of each zone of the twin-screw extruder are set as follows: zone 1 is 140-150℃, zone 2 is 155-160℃, zone 3 is 165-170℃, and zone 4 is 155-160℃; the process parameters for hot pressing are: temperature 160-170℃, pressure 10-15MPa, and hot pressing time 5-10min.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] The antibacterial polymer nanocomposite material provided by this invention significantly improves the antibacterial properties and mechanical stability of the material through the synergistic effect of multiple components. The material uses polyhydroxybutyrate and polybutylene adipate-terephthalate as the matrix to construct a good polymer network structure, ensuring the basic physical properties and processing adaptability of the composite material. The introduced non-metallic organic framework antibacterial agent, through its unique coordination structure, can efficiently convert oxygen in the environment into highly oxidizing singlet oxygen (¹O2) and other reactive oxygen species under visible light irradiation. These ROS can indiscriminately attack the bacterial cell membrane, proteins, and nucleic acids, inducing oxidative death of bacteria, thereby exerting a stable and long-lasting chemical antibacterial effect. The non-peptide antibacterial mimic mimic mimics the structural characteristics of natural antibacterial peptides. The quaternary ammonium salt cations in its molecular structure can be strongly adsorbed onto the negatively charged bacterial cell membrane through electrostatic interactions. Subsequently, its hydrophobic segment inserts into and disrupts the arrangement of the phospholipid bilayer, directly forming pores on the membrane, leading to leakage of cell contents, enhancing the ability to destroy bacterial cell membranes, and improving the broad spectrum and efficiency of antibacterial activity. Meanwhile, photothermal responsive nanomaterials can generate localized thermal effects when exposed to light or other excitation conditions, directly denaturing and inactivating bacterial proteins through physical means. Furthermore, they can increase the fluidity of bacterial cell membranes, significantly enhancing the membrane-breaking efficiency of non-peptide antibacterial mimics and the penetration and killing effects of ROS generated by non-metallic organic framework antibacterial agents, thereby strengthening overall antibacterial activity and effectively preventing the development of bacterial resistance. The rational design of the interface compatibilizer improves the interfacial bonding between components, promotes the uniform dispersion of nano-antibacterial components in the polymer matrix, and prevents nanoparticle aggregation, thus improving the activity release efficiency of the antibacterial components and the mechanical properties of the material. The addition of toughening agents improves the toughness and ductility of the material, enhancing the mechanical stability and durability of the composite material in practical applications. During the preparation process, a combination of solution blending and melt blending is used, ensuring not only the full deagglomeration and uniform dispersion of the nano-components but also achieving high-quality molding of the composite material, guaranteeing the structural integrity and performance consistency of the material. Attached Figure Description

[0033] Figure 1 This is a flowchart illustrating the preparation process of the antibacterial polymer nanocomposite material described in this invention.

[0034] Figure 2 This is a flowchart illustrating the preparation process of the non-peptide antibacterial mimicry described in this invention.

[0035] Figure 3 This is a flowchart illustrating the preparation process of the photothermal responsive nanomaterials described in this invention. Detailed Implementation

[0036] The present invention will now be clearly and completely described in conjunction with embodiments thereof. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0037] Please see Figure 1-3 The present invention provides a technical solution:

[0038] Example 1

[0039] This embodiment provides an antibacterial polymer nanocomposite material, comprising the following components by weight (one part by weight is defined as 100g):

[0040]

[0041] The polyhydroxybutyrate was purchased from Shanghai Mairui Biochemical Technology Co., Ltd., with product number M69249.

[0042] The poly(butylene adipate) terephthalate (PAT) is designated Ecoflex® F Blend C1200 and was purchased from BASF.

[0043] The non-metallic organic framework antibacterial agent is prepared through the following steps:

[0044] Tetra(4-aminophenyl)porphyrin and dimethylacetamide were dissolved in a mixed solvent of mesitylene and 1,4-dioxane at a molar ratio of 1:2 (solute / solvent mass ratio of 1:10), and acetic acid at a concentration of 3M was added as a catalyst. The reaction was carried out at 100°C for 72 h. The purple precipitate was collected by centrifugation, washed, and dried to obtain the non-metallic organic framework antibacterial agent.

[0045] In the mixed solvent, the volume ratio of pyromellitic acid and 1,4-dioxane is 1:2;

[0046] The amount of acetic acid added accounts for 2% of the total liquid volume of the mixed solvent;

[0047] The non-peptide antimicrobial mimicry is prepared by the following steps:

[0048] S11. Dissolve monomethoxy polyethylene glycol and cholic acid in anhydrous dichloromethane at a molar ratio of 1:2 (solute / solvent mass ratio of 1:15), and stir until a homogeneous solution is formed.

[0049] S12. Add N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine to the above solution, and stir the reaction at room temperature for 12 h under nitrogen protection. After the reaction is completed, filter to remove the byproduct dicyclohexylurea, precipitate the filtrate with ice-cold ether, collect the precipitate by centrifugation, wash it 3 times with cold ether, and dry it to obtain the cholic acid-polyethylene glycol copolymer.

[0050] S13. The cholic acid-polyethylene glycol copolymer was dissolved in anhydrous N,N-dimethylformamide (solute / solvent mass ratio of 1:10), and iodomethane and potassium carbonate were added. The reaction was carried out at 60°C for 8 hours to quaternize all hydroxyl groups on the cholic acid backbone. After the reaction was completed, the solution was dropped into anhydrous diethyl ether to precipitate the product. The product was collected by centrifugation, washed three times with diethyl ether, and dried to obtain the non-peptide antibacterial mimic.

[0051] In step S12, the molar ratio of N,N'-dicyclohexylcarbodiimide to cholic acid is 1:1.1;

[0052] In step S12, the molar ratio of 4-dimethylaminopyridine to cholic acid is 1:0.1;

[0053] In step S13, the molar ratio of iodomethane to bile acid is 1:5;

[0054] In step S13, the molar ratio of potassium carbonate to bile acid is 1:0.5;

[0055] The photothermal responsive nanomaterial is prepared through the following steps:

[0056] S21. Place the vanadium powder in an air atmosphere and heat-treat it at 350°C for 3 hours to allow its surface to oxidize naturally and form a layer of vanadium oxide.

[0057] S22. The heat-treated vanadium metal powder was dispersed in N-methylpyrrolidone at a concentration of 3 mg / mL (solid-liquid ratio 1:10). Under argon protection, the mixture was sonicated in an ice bath at 3°C ​​for 4 h using a probe sonicator (power: 600 W, on for 2 s and off for 3 s). Then, it was centrifuged (2000 rpm, 10 min) to remove the unpeeled thick-layer particles. After washing with ethanol and water alternately 3 times, it was vacuum dried at 60°C to constant weight to obtain the photothermal responsive nanomaterial.

[0058] The interface compatibilizer is a maleic anhydride-grafted interface compatibilizer, specifically model PP-g-MAH;

[0059] The toughening agent is further defined as a polyolefin elastomer toughening agent, specifically TAFMER™.

[0060] This embodiment also provides a method for preparing an antibacterial polymer nanocomposite material, including the following steps:

[0061] S1. Solution blending and pre-dispersion:

[0062] S101. Take half a part by weight of polyhydroxybutyrate and poly(butylene adipate-terephthalate) and dissolve them in chloroform. Stir mechanically in a water bath at 60°C to prepare a polymer solution with a total concentration of 5 wt%.

[0063] S102. Mix the non-metallic organic framework antibacterial agent, non-peptide antibacterial mimic, and photothermal responsive nanomaterials according to the mass ratio and add them to chloroform (solid-liquid ratio 1:15). Perform preliminary dispersion in an ice-water bath at 4°C to obtain a nano slurry.

[0064] S103. After adding the nano-slurry dropwise to the polymer solution under magnetic stirring (stirring speed 300 rpm), the polymer solution is heated to 40°C and ultrasonically treated for 1 hour while stirring (power: 300 W) to fully deagglomerate and uniformly disperse the nanoparticles.

[0065] S104. The uniformly dispersed solution obtained in step S103 is poured into a polytetrafluoroethylene pan and left to stand for 24 hours. Then it is dried at 40°C for 48 hours to completely remove the residual solvent. The dried blend is crushed into fine particles by a pulverizer to obtain a pre-dispersed composite masterbatch.

[0066] S2. Melt blending granulation

[0067] S201. Add the pre-dispersed masterbatch, the remaining polyhydroxybutyrate, the remaining polybutylene adipate terephthalate, the interface compatibilizer, and the toughening agent to a high-speed mixer and mix at 600 rpm for 10 min to make the components initially uniformly mixed.

[0068] S202. The premixed material is added to a twin-screw extruder for extrusion. The extrudate is water-cooled, air-dried, and granulated by a pelletizer. After drying, it is hot-pressed to obtain the antibacterial polymer nanocomposite material.

[0069] In step S202, the temperatures of each zone of the twin-screw extruder are set as follows: zone 1 is 140℃, zone 2 is 155℃, zone 3 is 165℃, and zone 4 is 155℃; the screw speed is set to 200 rpm; and the hot pressing process parameters are: temperature is 170℃, pressure is 15 MPa, and hot pressing time is 10 min.

[0070] Example 2: Example 2 differs from Example 1 in that, in Example 2, the antibacterial polymer nanocomposite material comprises the following components by weight (one part by weight is defined as 100g):

[0071]

[0072] The remaining steps are exactly the same as in Example 2 and Example 1.

[0073] Example 3: Example 3 differs from Example 1 in that, in Example 3, the antibacterial polymer nanocomposite material comprises the following components by weight (one part by weight is defined as 100g):

[0074]

[0075] The remaining steps are exactly the same as in Example 3 and Example 1.

[0076] Comparative Example

[0077] Comparative Example 1: The only difference between Comparative Example 1 and Example 1 is that the non-metallic organic framework antibacterial agent originally present in Example 1 was omitted in Comparative Example 1. The remaining steps are exactly the same in Comparative Example 1 and Example 1.

[0078] Comparative Example 2: The only difference between Comparative Example 2 and Example 1 is that the non-peptide antimicrobial mimicry originally present in Example 1 was removed in Comparative Example 2. The remaining steps are exactly the same in Comparative Example 2 and Example 1.

[0079] Comparative Example 3: The only difference between Comparative Example 3 and Example 1 is that the use of photothermal responsive nanomaterials, which were present in Example 1, was omitted in Comparative Example 3. The remaining steps are exactly the same in Comparative Example 3 and Example 1.

[0080] Comparative Example 4: The only difference between Comparative Example 4 and Example 1 is that the non-metallic organic framework antibacterial agent and non-peptide antibacterial mimic that were present in Example 1 were removed in Comparative Example 4. The remaining steps are exactly the same in Comparative Example 4 and Example 1.

[0081] Performance testing:

[0082] Referring to the test scheme specified in Chinese National Standard GB / T 31402-2015 "Test Methods and Antibacterial Effects of Plastics", the antibacterial properties of Examples 1-3 and Comparative Examples 1-4 were tested. The specific steps are as follows:

[0083] Sample preparation: The composite materials prepared in each example and comparative example were hot-pressed into square sheet-like specimens with a thickness of (2.0±0.1) mm and a side length of (50±2) mm. All specimens were surface sterilized by ultraviolet irradiation (30 W, 1 m distance, 30 min) before testing;

[0084] Bacterial strains and culture: The test strains were *Escherichia coli* (ATCC 25922) and *Staphylococcus aureus* (ATCC 6538), representing Gram-negative and Gram-positive bacteria, respectively. The strains were activated and subcultured according to *GB 4789.28-2013 Quality Requirements for Culture Media and Reagents for Microbiological Testing in Food*, and cultured in nutrient broth at (37 ± 1)℃ until the logarithmic growth phase. The cultures were then diluted with phosphate-buffered saline (PBS) to a concentration of approximately 1 × 10⁻⁶. 6 CFU / mL bacterial suspension;

[0085] Inoculation and contact: 0.1 mL of bacterial suspension was evenly dropped onto the sample surface and covered with a sterile polyethylene film (40 mm × 40 mm) to prevent evaporation. The sample was then incubated at (37 ± 1) °C and relative humidity >90% for 24 h. A blank control (PBS solution only) and a positive control (pure PHB / PBAT substrate without antibacterial treatment) were also set up.

[0086] Viable cell count: After contact, the sample was placed in a test tube containing 10 mL of neutralizing agent (PBS solution containing 0.5% sodium thiosulfate and 1.0% Tween 80), and vortexed for 1 min to fully elute the bacteria. The eluent was serially diluted and incubated on nutrient agar plates at (37 ± 1) °C for 24 h using the pour plate method. Colony-forming units were then counted, and the antibacterial rate (%) was calculated according to the formula:

[0087] Antibacterial rate = [(A - B) / A] × 100%;

[0088] Where A represents the average viable bacterial count (CFU / tablet) of the blank control sample after 24 hours of incubation, and B represents the average viable bacterial count (CFU / tablet) of the antibacterial material sample after 24 hours of incubation. According to GB / T 31402-2015, an antibacterial rate ≥ 90% indicates that the material has an antibacterial effect, and ≥ 99% is considered to have a strong antibacterial effect. The relevant test results are shown below:

[0089]

[0090] As can be seen from the above, the antibacterial rates of Examples 1 to 3 all far exceed 99%, demonstrating strong antibacterial effects. Their high performance stems from a multi-layered synergistic antibacterial mechanism formed by the non-metallic organic framework antibacterial agent, the non-peptide antibacterial mimic, and the photothermal responsive nanomaterials. Under ambient light, the non-metallic organic framework antibacterial agent can catalyze the generation of reactive oxygen species (ROS), such as singlet oxygen (¹O2), causing irreversible oxidative damage to bacterial proteins, lipids, and DNA. The non-peptide antibacterial mimic, due to the positive charge of its quaternary ammonium salt groups, adsorbs onto the negatively charged bacterial cell membrane through electrostatic interactions. Its hydrophobic segments then insert and physically disrupt the phospholipid bilayer structure, leading to leakage of cell contents. Under near-infrared light irradiation, the photothermal responsive nanomaterials can generate localized high temperatures (photothermal effect), which not only directly denatures bacterial proteins but, more importantly, enhances cell membrane fluidity, thereby significantly promoting the penetration efficiency of the aforementioned ROS and the membrane-breaking efficiency of the non-peptide mimic. The synergistic effect of these three antibacterial mechanisms forms a three-dimensional attack network, making it difficult for bacteria to develop effective drug resistance pathways. Therefore, the examples demonstrate highly efficient and broad-spectrum antibacterial properties.

[0091] In contrast, Comparative Example 1 (lacking non-metallic organic framework antibacterial agents) showed a significant decrease in antibacterial rate to around 85%. This is because the material lost the core chemical attack mechanism of photocatalytic generation of reactive oxygen species (ROS). Although physical membrane disruption and photothermal effects still existed, the lack of ROS oxidative damage to bacterial macromolecules resulted in incomplete sterilization, particularly weakening its effectiveness against some drug-resistant bacteria. This confirms the crucial contribution of the oxidative killing mechanism in the synergistic system. Comparative Example 2 (lacking non-peptide antibacterial mimics) showed a reduced antibacterial rate to approximately 80%, primarily due to the loss of the rapid and non-drug-resistant physical mechanism of contact-based physical membrane disruption. Without non-peptide mimics to initially disrupt cell membrane integrity, subsequent ROS and photothermal effects could not effectively penetrate the bacterial cell, leading to a significant reduction in overall antibacterial efficiency. This indicates that physical membrane disruption is fundamental to synergistic antibacterial action. Comparative Example 3 (lacking photothermal responsive nanomaterials) showed an antibacterial rate of approximately 82%, its deficiency being the lack of auxiliary enhancement from the photothermal effect. The photothermal effect not only provides independent thermal killing, but more importantly, it improves membrane permeability and enhances the efficacy of the other two antibacterial mechanisms. Without this step, the synergistic efficiency of chemical oxidation and physical membrane disruption is not optimal, limiting the antibacterial speed and depth of action. Comparative Example 4 (lacking both non-metallic organic framework antibacterial agents and non-peptide antibacterial mimics) exhibited the lowest antibacterial performance, at only about 50%. This is because the material simultaneously lost both chemical oxidation (ROS) and physical membrane disruption, leaving only the photothermal effect as a single mechanism, which is insufficient to cause a fatal blow to bacteria. This fully demonstrates the necessity and superiority of the synergistic effect of multiple mechanisms in this invention. Finally, the positive control (pure polymer substrate) showed almost no antibacterial ability, indicating that the antibacterial performance of this composite material originates entirely from the added functional nanocomponents and their synergistic effects.

[0092] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An antibacterial polymer nanocomposite material, characterized in that, The product comprises the following components by weight: 40-50 parts polyhydroxybutyrate, 20-30 parts polybutylene adipate terephthalate, 4-7 parts non-metallic organic framework antibacterial agent, 5-9 parts non-peptide antibacterial mimic, 3-6 parts photothermal responsive nanomaterials, 3-5 parts interface compatibilizer, and 2-4 parts toughening agent. The non-metallic organic framework antibacterial agent is prepared through the following steps: Tetra(4-aminophenyl)porphyrin and dimethylacetamide were dissolved in a mixed solvent of mesitylene and 1,4-dioxane at a molar ratio of 1-2:2-4, and acetic acid at a concentration of 3-6M was added as a catalyst. The reaction was carried out at 100-120℃ for 72-80 h. The purple precipitate was collected by centrifugation, washed, and dried to obtain the non-metallic organic framework antibacterial agent. The non-peptide antimicrobial mimicry is prepared by the following steps: S11. Dissolve monomethoxy polyethylene glycol and cholic acid in anhydrous dichloromethane at a molar ratio of 1-2:2-4, and stir until a homogeneous solution is formed; S12. Add N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine to the above solution, and stir the reaction at room temperature for 12-24 h under nitrogen protection. After the reaction is completed, filter to remove the byproduct dicyclohexylurea, precipitate the filtrate with ice-cold ether, collect the precipitate by centrifugation, wash it with cold ether 3-4 times, and dry it to obtain the cholic acid-polyethylene glycol copolymer. S13. Dissolve the cholic acid-polyethylene glycol copolymer in anhydrous N,N-dimethylformamide, add iodomethane and potassium carbonate, react at 60-80°C for 6-8 hours, after the reaction is completed, drop the solution into anhydrous diethyl ether to precipitate, collect the product by centrifugation, wash with diethyl ether 3-4 times, and dry to obtain the non-peptide antibacterial mimic. The photothermal responsive nanomaterial is prepared through the following steps: S21. Place the vanadium powder in an air atmosphere and heat-treat it at 350-400℃ for 2-3 hours to allow its surface to oxidize naturally and form a layer of vanadium oxide. S22. Disperse the heat-treated vanadium powder in N-methylpyrrolidone at a concentration of 1-3 mg / mL, sonicate in an ice bath at 0-3℃ for 4-6 h under argon protection using a probe sonicator, then centrifuge for 10-15 min, wash with ethanol and water alternately 3-4 times, and vacuum dry at 60-80℃ to constant weight to obtain the photothermal responsive nanomaterial.

2. The antibacterial polymer nanocomposite material according to claim 1, characterized in that, In the mixed solvent, the volume ratio of tricresylbenzene to 1,4-dioxane is 1-2:1-2.

3. The antibacterial polymer nanocomposite material according to claim 1, characterized in that, The amount of acetic acid added accounts for 1-2% of the total liquid volume of the mixed solvent.

4. The antibacterial polymer nanocomposite material according to claim 1, characterized in that, In step S12, the molar ratio of N,N'-dicyclohexylcarbodiimide to cholic acid is 1:1.1-1.3; the molar ratio of 4-dimethylaminopyridine to cholic acid is 1:0.1-0.

2. In step S13, the molar ratio of iodomethane to bile acid is 1:5-6; the molar ratio of potassium carbonate to bile acid is 1:0.5-0.

6.

5. The antibacterial polymer nanocomposite material according to claim 1, characterized in that, The interface compatibilizer is a maleic anhydride-grafted interface compatibilizer; the toughening agent is a polyolefin elastomer-type toughening agent.

6. A method for preparing an antibacterial polymer nanocomposite material, used to prepare the antibacterial polymer nanocomposite material according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Solution blending and pre-dispersion: S101. Take half a part by weight of polyhydroxybutyrate and polybutylene adipate-terephthalate respectively, dissolve them in chloroform, and mechanically stir in a water bath at 60-80℃ to prepare a polymer solution with a total concentration of 5-7 wt%. S102. Mix the non-metallic organic framework antibacterial agent, non-peptide antibacterial mimic, and photothermal responsive nanomaterials according to the mass ratio and add them to chloroform. Perform preliminary dispersion in an ice-water bath at 0-4℃ to obtain a nano slurry. S103. The nano-slurry is added dropwise to the polymer solution, and ultrasonically treated at 40-50℃ for 1-2 hours while stirring, so that the nanoparticles are fully deagglomerated and uniformly dispersed. S104. The uniformly dispersed solution obtained in step S103 is poured into a disc container and left to stand for 24-48 hours. Then it is dried at 40-50℃ for 24-48 hours to completely remove the residual solvent. The dried blend is then crushed into fine particles using a pulverizer to obtain a pre-dispersed composite masterbatch. S2. Melt blending granulation: S201. Add the pre-dispersed composite masterbatch, the remaining polyhydroxybutyrate, the remaining poly(butylene adipate-terephthalate), the interface compatibilizer, and the toughening agent to a high-speed mixer and mix for 5-10 minutes to make the components initially uniformly mixed. S202. The premixed material is added to a twin-screw extruder for extrusion. The extrudate is water-cooled, air-dried, and granulated by a pelletizer. After drying, it is hot-pressed to obtain the antibacterial polymer nanocomposite material.

7. The method for preparing an antibacterial polymer nanocomposite material according to claim 6, characterized in that, In step S202, the temperatures of each zone of the twin-screw extruder are set as follows: zone 1 is 140-150℃, zone 2 is 155-160℃, zone 3 is 165-170℃, and zone 4 is 155-160℃; the process parameters for hot pressing are: temperature is 160-170℃, pressure is 10-15MPa, and hot pressing time is 5-10min.

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