A polymer-loaded drug nanoparticle with high encapsulation efficiency and its application in coatings and surface film materials.

Abstract

This invention discloses a polymer-loaded drug-eluting nanoparticle with high encapsulation efficiency and its application in coatings and surface film materials. The polymer-loaded drug-eluting nanoparticles are prepared via emulsion polymerization, simultaneously loading antibacterial drugs with different log P values. The preparation process is simple, and the resulting product has small particle size, high molecular weight, high uniformity, and high drug encapsulation efficiency, achieving the substitution of non-reactive surfactants with reactive surfactants. A coating can be prepared using the above-mentioned polymer-loaded drug-eluting nanoparticles. The coating can be further used to prepare sustained-release antibacterial surface film materials through cross-linking film formation, exhibiting good mechanical properties, excellent chemical resistance, and high safety. This invention can be widely applied to various environmental and material surfaces, including but not limited to surface modification of instruments and building materials in residential and medical environments, thereby achieving a long-lasting antibacterial effect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of antibacterial materials. Specifically, it relates to the preparation of polymer drug-loaded nanoparticles with high encapsulation efficiency and its application in coatings and surface film materials. BACKGROUND

[0002] Microorganisms are one of the oldest species on earth, and they are ubiquitous in all biological communities and widely exist in human production and living environment. Most microorganisms are harmless to humans and can be used to manufacture food, chemicals, etc. However, a part of microorganisms such as Escherichia coli, Staphylococcus aureus, and Aspergillus niger can rapidly reproduce under appropriate environmental conditions, leading to material mold, corruption, and wound infection, etc., which has caused many adverse effects on human health.

[0003] Traditional antibacterial methods include ultraviolet antibacterial, alcohol disinfection, high-temperature sterilization, etc., but the above strategies have problems such as short antibacterial time, repeated and tedious operation, limited use environment, potential safety risks, etc. For example, Manuela Lualdi et al. (BMC Infect Dis. 2021, 21, 594) designed a complex ultraviolet LED lamp with different aluminum layers to supplement the current hospital cleaning and disinfection of surfaces contaminated by SARS-CoV-2, which improved safety but was high in cost and had antibacterial lag. The surface modification strategy fundamentally endows the material with antibacterial properties, making up for the defects of the former, and the high polymer forms a dense and smooth coating on the surface. Esmeryan, K. D. (Mater. Des. 2018, 160, 395-404) inspired by nature, used superhydrophobic structures to reduce microbial adhesion, but did not have bactericidal or bacteriostatic activity, and there was still a risk of contamination in the non-hydrophobic area; Luyun Cai et al. (J Agric. Food Chem. 2020, 68, 7453-7466) used Pickering emulsion to load antibacterial peptides, but the drug loading and encapsulation efficiency were low, and the emulsion stability was poor.

[0004] Therefore, it is necessary to establish a safer, more stable, and more effective antibacterial method. Slow-release antibacterial surface film material is a new antibacterial strategy, which can form a slow-release antibacterial film on the surface of the material, thereby achieving sustained inhibition of surface microorganisms. Compared with traditional antibacterial methods, slow-release antibacterial surface film material has many advantages, such as strong controllability, long-lasting bacteriostatic effect, non-migration, safety to human body, etc. In summary, it is of great practical significance to use a stable and easily obtained slow-release drug delivery system to improve the antibacterial ability of various instrument materials. SUMMARY

[0005] The present application aims to provide a polymer drug-loaded nanoparticle with high encapsulation efficiency and a preparation method thereof. The method is mild in conditions, low in cost, simple in operation and easy for industrial production.

[0006] Another object of the present application is to provide a film forming method of the polymer drug-loaded nanoparticle. The method comprises a preparation method of a coating and a preparation method of a surface film material based on the coating.

[0007] Another object of the present application is to provide an application of the polymer drug-loaded nanoparticle in a sustained-release antibacterial surface film material.

[0008] In one aspect, the present application provides a polymer drug-loaded nanoparticle with high encapsulation efficiency and a preparation method thereof. The nanoparticle is prepared by emulsion polymerization and comprises the following steps:

[0009] Part of the emulsifier is added into water, and then the monomer and the antibacterial drug are sequentially added. The mixture is stirred at 600 rpm for 3-12 h to prepare a stable monomer pre-emulsion A. Part of the initiator is dissolved in deionized water to prepare a solution B with a mass concentration of 3%-5%. Sodium bicarbonate and part of the emulsifier are dissolved in deionized water to prepare a solution C. Part of the initiator is dissolved in deionized water to prepare a solution D with a mass concentration of 2%-3%. The oxidizing agent is dissolved in deionized water to prepare a solution E with a mass concentration of 4%-6%. The reducing agent is dissolved in deionized water to prepare a solution F with a mass concentration of 4%-6%. The pH regulator is dissolved in deionized water to prepare a solution G with a mass concentration of 50%.

[0010] The solution C is added into a 1L jacketed glass reactor equipped with a condenser, a thermometer and a stirring paddle. After nitrogen replacement, the reaction temperature is increased to 85℃, and the stirring is started. 5% of the monomer pre-emulsion A is taken as a seed and added into the reactor. After stirring for 3-5 min, the solution B is added. The stirring is continued for 20-30 min. Then, the monomer pre-emulsion A and the solution D are simultaneously added dropwise. The remaining monomer pre-emulsion A is uniformly added within 3 h. The solution D is uniformly added within 3 h 15 min. After the dropwise addition is completed, the reaction temperature is decreased to 65℃, and the solutions E and F are simultaneously added dropwise within 30 min. After the dropwise addition is completed, the reaction temperature is decreased to 40℃, and the solution G is added at once. After stirring for 10 min, the pH value is 8-9. The polymer drug-loaded nanoparticle aqueous dispersion is obtained by passing through a 200 mesh filter.

[0011] Preferably, the monomer used in the preparation of the polymer-loaded drug nanoparticles may be one or more of styrene, acrylic monomers, and methacrylic monomers; more preferably, it may be one or more of styrene, ethyl acrylate, butyl acrylate, isooctyl acrylate, methyl methacrylate, butyl methacrylate, hydroxyethyl methacrylate, and β-hydroxypropyl methacrylate purchased from Anaiji Chemical Reagent Company; most preferably, the monomer may be styrene, methyl methacrylate, butyl methacrylate, and hydroxyethyl methacrylate.

[0012] Preferably, the initiator used in the preparation of the polymer-loaded drug nanoparticles can be a peroxide, persulfate, or azo initiator; more preferably, it can be benzoyl peroxide, di-tert-butyl peroxide, potassium persulfate, sodium persulfate, ammonium persulfate, azobisisobutyronitrile, azobisisoheptanenitrile, or azobisisobutyramidine hydrochloride purchased from Anaiji Chemical Reagent Company; most preferably, the initiator is azobisisobutyronitrile or azobisisobutyramidine hydrochloride.

[0013] Preferably, the redox system used in the preparation of the polymer-loaded drug nanoparticles can be tert-butyl hydroperoxide / sodium metabisulfite, tert-butyl hydroperoxide / FF6M, benzoyl peroxide / N,N-dimethylaniline, benzoyl peroxide / FF6M, ammonium persulfate / sodium bisulfite, or hydroperoxide / FF6M; more preferably, the redox system can be tert-butyl hydroperoxide / FF6M. FF6M was purchased from Germany. Chemical Company. The remaining reagents were purchased from Anaiji Chemical Reagent Company.

[0014] Preferably, the surfactant used in the preparation of the polymer-loaded drug nanoparticles can be one or two of the non-reactive surfactants sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, and sodium secondary alkyl sulfonate purchased from Anaiji Chemical Reagent Co., Ltd., and the reactive surfactants ADEKA REASOAP SE-10N, ADEKA REASOAP SR-10, ADEKA REASOAP SR-1025, ADEKA REASOAPER-10, ADEKA REASOAPER-20, ADEKA REASOAPER-30, or ADEKA REASOAP 70 purchased from Adeka Co., Ltd. of Japan; more preferably, it can be one or two of sodium dodecylbenzene sulfonate, ADEKA REASOAP SR-10, or ADEKA REASOAPER-30.

[0015] Preferably, the pH adjuster used in the preparation of the polymer-loaded drug nanoparticles can be sodium carbonate, sodium bicarbonate, ammonia, dimethylethanolamine, N-methylethanolamine, butylethanolamine, etc., purchased from Anaiji Chemical Reagent Company; more preferably, it can be dimethylethanolamine.

[0016] Preferably, the antibacterial drug loaded on the polymer-loaded nanoparticles is an organic compound with antibacterial activity in the logP range of 0.5-6, and does not react with the initiator; more preferably, it is an organic compound with antibacterial activity in the logP range of 1-3, and does not react with the initiator; most preferably, it is n-butyl-1,2-benzisothiazolin-3-one (CAS4299-07-4), iodopropynyl butylcarbamate (CAS 55406-53-6), 2-phenoxyethanol (CAS 122-99-6), or ethylparaben (CAS 120-47-8), and does not react with the initiator. All reagents were purchased from Anaiji Chemical Reagent Co., Ltd.

[0017] Preferably, the ratio (w / w) of monomer to water used in the preparation of the polymer nanoparticles can be 1:0.5-1:2, such as 1:0.5, 1:0.8, 1:1, 1:1.2, 1:1.5, 1:1.8, or 1:2, etc. More preferably, the ratio of monomer to water is 1:1.1-1:1.2. The weight (w) is calculated in grams (g).

[0018] Preferably, the ratio (W / W) of the initiator to the monomer used in the preparation of the polymer-loaded nanoparticles can be 1%-10%, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%; more preferably, the ratio of the initiator to the monomer is 3%-5%. The weight (W) is calculated in grams (g).

[0019] Preferably, the ratio (w / w) of the redox system added to the monomer added during the preparation of the polymer-loaded drug nanoparticles is 0.05%-0.5%, for example, 0.05%, 0.06%, 0.08%, 0.1%, 0.2%, 0.3%, 0.4%, or 0.5%; more preferably, the ratio of the redox system added to the monomer added is 0.2%. All weight (w) is expressed in grams (g).

[0020] Preferably, the ratio (W / W) of the antibacterial drug added to the monomer added during the preparation of the polymer-loaded nanoparticles is 0.5%-10%, for example, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%; more preferably, the ratio of the antibacterial drug added to the monomer added is 1%. The weight (W) is calculated in grams (g).

[0021] Preferably, the reaction temperature used in the preparation of the polymer-loaded drug nanoparticles can be: 80-90℃ in the initial stage, 60-70℃ in the middle stage, and 35-45℃ in the final stage, such as 80℃-65℃-40℃, 80℃-60℃-45℃, 85℃-65℃-45℃, 85℃-70℃-40℃, 85℃-70℃-45℃, 90℃-60℃-45℃, or 90℃-65℃-45℃, etc.; more preferably, the reaction temperature can be: 85℃ in the initial stage, 65℃ in the middle stage, and 40℃ in the final stage.

[0022] Preferably, the ratio (w / w) of the pH adjuster to the monomer used in the preparation of the polymer-loaded nanoparticles can be 0.05%-2%, for example, 0.05%, 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1%, 1.5%, or 2%; more preferably, the ratio of the pH adjuster to the monomer is 0.4%-0.8%. All weight (w) is expressed in grams (g).

[0023] Preferably, the stirring method can be mechanical stirring with a speed of 200 rpm, 300 rpm, 400 rpm, 500 rpm, 600 rpm, 700 rpm, 900 rpm, 1000 rpm, 1250 rpm, or 1500 rpm; more preferably, the stirring speed is 1000 rpm.

[0024] Preferably, the antibacterial drug can be added to the pre-emulsion or blended into the shell pre-emulsion via core-shell polymerization; more preferably, it can be added by blending into the shell pre-emulsion via core-shell polymerization.

[0025] Preferably, the polymer-loaded drug nanoparticles have a weight-average molecular weight of 20,000-40,000 and an average particle size of 100-200 nm.

[0026] On the other hand, the present invention provides a method for preparing a coating based on the above-mentioned polymer-loaded drug nanoparticles. This includes the following steps;

[0027] Weigh the aqueous dispersion of polymer nanoparticles and place it in a flask. Add deionized water at a mass ratio of 1:1 for dilution and dispersion. Then add 5% crosslinking agent, 1.5% film-forming aid, 0.3% wetting and leveling agent, and 0.03% defoamer. Stir with a magnetic stirrer at 800 rpm for 10 minutes to fully disperse the various aids. The addition ratio of each aid is the ratio of the mass of the aid to the mass of the aqueous dispersion of polymer nanoparticles after dilution with water.

[0028] Preferably, the crosslinking agent may be Aquolin 268, Aquolin 269, Aquolin 270, Aquolin 278 or Aquolin 280 purchased from Wanhua Chemical Company; more preferably, it may be Aquolin 268.

[0029] Preferably, the film-forming aid may be ethylene glycol, propylene glycol, hexanediol, dipropylene glycol n-butyl ether, dipropylene glycol monomethyl ether, polyethylene glycol (molecular weight 200), ethylene glycol butyl ether acetate, or hexanediol diacetate, etc.; more preferably, it may be dipropylene glycol monomethyl ether.

[0030] Preferably, the wetting and leveling agent may be one or two of BYK-151, BYK-153, BYK-301, BYK-333, BYK-346, BYK-348 or BYK-361N purchased from BYK Corporation; more preferably, it may be one or two of BYK-333 or BYK-346.

[0031] Preferably, the defoamer may be Tego Pren 5840, Tego Pren 5885, Tego Airex 902W, Surfynol AD01, Surfynol MD20 or Surfynol 465, etc., purchased from Evonik Specialty Chemicals (Shanghai) Co., Ltd.; more preferably, it may be TegoAirex 902W.

[0032] Thirdly, the present invention provides a surface film-forming method based on the above-mentioned coating. The method involves forming a film on a substrate surface using the above-mentioned coating through a crosslinking process, comprising the following steps:

[0033] Weigh 1.00g of coating and drop it onto the substrate surface. Then, use a wet film coater to horizontally scrape a film onto the substrate surface. Let it stand until the moisture evaporates to obtain the surface film material.

[0034] Preferably, the substrate may be nylon cloth, glass plate, engineering plastic alloy plate (ABS+PC), thermoplastic polyester plate (PET), or carbon fiber plate, etc. The substrate includes, but is not limited to, the above-mentioned substrate types.

[0035] Fourthly, this invention provides applications of the aforementioned sustained-release antibacterial surface film material. Surface film materials are prepared on various substrates through the simple, rapid, and reliable film-forming process described above. The antibacterial effect of the sustained-release antibacterial surface film material is evaluated by conducting antifungal and antibacterial tests. Simultaneously, the sustained-release capacity is tested using water dialysis to evaluate the sustained-release effect. Furthermore, the biosafety of the surface film material is further studied. This achieves a safe and efficient sustained-release antibacterial effect for commonly used medical devices that come into contact with humans in the environment.

[0036] The present invention has the following advantages over the prior art:

[0037] First, a novel method for synthesizing polymer-loaded nanoparticles with high encapsulation efficiency and loading of antibacterial drugs with different log P values ​​was established for the first time, achieving an encapsulation efficiency of over 90%. Reactive surfactants were used to completely replace traditional free surfactants, reducing the potential toxicity of the polymer nanoparticle system and improving the stability and uniformity of the aqueous dispersion. Second, the film-forming process of polymer-loaded nanoparticle aqueous dispersions was applied to the field of antibacterial surface film formation for the first time. Based on this, transparent surface film materials with high mechanical strength and good chemical resistance can be prepared. The cross-linking film-forming method resulted in isocyanate group residues of less than 1%, further reducing the potential toxicity of the material. Third, surface modification of various substrates based on sustained-release antibacterial surface materials was achieved, thereby realizing surface antibacterial properties. The prepared surface film materials exhibited superior sustained-release antibacterial performance and good biosafety evaluation, achieving long-lasting broad-spectrum antibacterial activity against common bacteria and fungi. Attached Figure Description

[0038] Figure 1 This is a graph showing the chemical resistance test results of the sustained-release antibacterial surface film material prepared based on polymer-loaded drug nanoparticles in this invention.

[0039] Figure 2 This is a graph showing the detection results of the film-forming process of the sustained-release antibacterial surface film material prepared based on polymer-loaded drug nanoparticles in this invention.

[0040] Figure 3 This is a molding effect diagram of the sustained-release antibacterial surface film material prepared based on polymer drug-loaded nanoparticles in this invention.

[0041] Figure 4 This is a graph showing the leachate test results of the sustained-release antibacterial surface membrane material prepared based on polymer-loaded drug nanoparticles in this invention.

[0042] Figure 5 This is a graph showing the test results of the antifungal performance of the sustained-release antibacterial surface film material prepared based on polymer-loaded drug nanoparticles in this invention.

[0043] Figure 6This is a graph showing the test results of the antibacterial performance of the sustained-release antibacterial surface film material prepared based on polymer-loaded drug nanoparticles in this invention.

[0044] Figure 7 This is a graph showing the test results of the sustained-release performance of the sustained-release antibacterial surface film material prepared based on polymer-loaded drug nanoparticles in this invention. Detailed Implementation

[0045] The following are some preferred embodiments of the present invention to further explain the advantages of the present invention. However, the following description is only for explaining the present invention and does not limit its content.

[0046] Example 1: Preparation and characterization of an aqueous dispersion of polymer-loaded drug nanoparticles

[0047] Add 0.89g sodium dodecylbenzenesulfonate and 2.50g ADEKAREASOAP SR-10 to 55.50g deionized water, then add 0.94g styrene, 22.00g methyl methacrylate, 79.60g butyl methacrylate and 10.20g hydroxyethyl methacrylate sequentially. Add 1.04g n-butyl-1,2-benzisothiazolin-3-one by blending with hydroxyethyl methacrylate. Stir at high speed for 3-12h to obtain a stable monomer preemulsion A.

[0048] Prepare solution B by dissolving 0.06 g of initiator azobisisobutyramidine hydrochloride in 5.00 g of deionized water;

[0049] Prepare solution C by dissolving 0.20g sodium bicarbonate and 1.33g sodium dodecylbenzenesulfonate in 60.00g deionized water;

[0050] Prepare solution D by dissolving 0.19 g of initiator azobisisobutyramidine hydrochloride in 12.00 g of deionized water;

[0051] Prepare solution E by dissolving 0.14 g of 70% tert-butyl hydrogen peroxide aqueous solution in 2.00 g of deionized water;

[0052] Prepare solution F by dissolving 0.12g of BRUGGOLITE FF6M in 2.00g of deionized water;

[0053] Prepare solution G by dissolving 1.00g of pH adjuster dimethylethanolamine in 1.00g of deionized water.

[0054] Solution C was added to a 1L jacketed glass reactor equipped with a condenser, thermometer, and stirrer. After purging with nitrogen, the reaction temperature was raised to 85℃, and stirring was started (D=40mm, 1000rpm). 5% by mass of monomer pre-emulsion A was added as a seed to the reactor, and after stirring for 3.5 min, solution B was added, and stirring continued for 20-30 min. Then, monomer pre-emulsion A and solution D were added dropwise simultaneously. The remaining monomer pre-emulsion A was added at a uniform rate over 3 hours; solution D was added at a uniform rate over 3 hours and 15 minutes. After the addition was complete, the reaction temperature was lowered to 65℃, and solutions E and F were added dropwise simultaneously, completed over 30 min. After the addition was complete, the reaction temperature was lowered to 40℃, and solution G was added all at once. After stirring for 10 min, the pH was 8.9. The solution was then filtered through a 200-mesh filter to obtain the polymer-loaded drug nanoparticle aqueous dispersion A-1. A-1 was freeze-dried using a vacuum freeze dryer to obtain freeze-dried particles A-1G.

[0055] The basic properties of the obtained polymer-loaded drug nanoparticle aqueous dispersion A-1 are as follows:

[0056] The product has a milky white appearance with a bluish tint, a pH of 9.57, a yield of 87.67%, and a solids content of 44.67%.

[0057] The particle size of A-1 was analyzed using a nanoparticle size and zeta potential analyzer. The average particle size was 139.60 nm and the polydispersity index (PDI) was 0.023.

[0058] Stability analysis of A-1 was performed using a stability analyzer, and its stability index (TsI) was 1.45.

[0059] The molecular weight of A-1G was analyzed by gel permeation chromatography (GPC), and its number-average molecular weight was 32,107 and its weight-average molecular weight was 34,772.

[0060] The encapsulation efficiency of A-1G was determined by high performance liquid chromatography (HPLC), and the encapsulation efficiency was 85.89 ± 0.64%.

[0061] Example 2: Preparation and characterization of an aqueous dispersion of polymer-loaded drug nanoparticles

[0062] Add 0.89g sodium dodecylbenzenesulfonate and 2.50g ADEKAREASOAP SR-10 to 55.50g deionized water, then add 0.94g styrene, 22.00g methyl methacrylate, 79.60g butyl methacrylate, and 10.20g hydroxyethyl methacrylate. 1.04g n-butyl-1,2-benzisothiazolin-3-one was then mixed with hydroxyethyl methacrylate and dispersed in a 33% system in another bottle. The mixture was stirred at high speed for 3-12 hours to obtain stable monomer preemulsions A and H.

[0063] Prepare solution B by dissolving 0.10 g of initiator azobisisobutyramidine hydrochloride in 5.00 g of deionized water;

[0064] Prepare solution C by dissolving 0.20g sodium bicarbonate and 1.33g sodium dodecylbenzenesulfonate in 60.00g deionized water;

[0065] Prepare solution D by dissolving 0.32 g of initiator azobisisobutyramidine hydrochloride in 12.00 g of deionized water;

[0066] Prepare solution E by dissolving 0.14 g of 70% tert-butyl hydrogen peroxide aqueous solution in 2.00 g of deionized water;

[0067] Prepare solution F by dissolving 0.12g of BRUGGOLITE FF6M in 2.00g of deionized water;

[0068] Prepare solution G by dissolving 1.00g of pH adjuster dimethylethanolamine in 1.00g of deionized water.

[0069] Solution C was added to a 1L jacketed glass reactor equipped with a condenser, thermometer, and stirrer. After purging with nitrogen, the reaction temperature was raised to 85℃, and stirring was started (D=40mm, 1000rpm). 7.5% by mass of monomer preemulsion A was added as a seed to the reactor, and after stirring for 3-5 minutes, solution B was added, and stirring continued for 20-30 minutes. Then, monomer preemulsion A and solution D were added dropwise simultaneously. The remaining monomer preemulsion A was added at a uniform rate over 2 hours, followed by preemulsion H at a uniform rate over the remaining hour. Solution D was added at a uniform rate over 3 hours and 15 minutes. After the addition was complete, the reaction temperature was lowered to 65℃, and solutions E and F were added dropwise simultaneously, completing the addition over 30 minutes. After the addition was complete, the reaction temperature was lowered to 40℃, and solution G was added all at once. After stirring for 10 minutes, the pH was 8-9. The solution was then filtered through a 200-mesh filter to obtain polymer-loaded drug nanoparticle aqueous dispersion A-2. A-2 was freeze-dried using a vacuum freeze dryer to obtain freeze-dried particles A-2G.

[0070] The basic properties of the obtained polymer-loaded drug-coated nanoparticle aqueous dispersion A-2 are as follows:

[0071] The product has a milky white appearance with a bluish tint, a pH of 9.37, a yield of 90.67%, and a solids content of 41.05%.

[0072] The particle size of A-2 was analyzed using a nanoparticle size and zeta potential analyzer. The average particle size was 150.14 nm and the polydispersity index (PDI) was 0.060.

[0073] Stability analysis of A-2 was performed using a stability analyzer, and its stability index (TsI) was 1.10.

[0074] The molecular weight of A-2G was analyzed by gel permeation chromatography (GPC), and its number-average molecular weight was 32016 and its weight-average molecular weight was 34423.

[0075] The encapsulation efficiency of A-2G was determined by high performance liquid chromatography (HPLC), and the encapsulation efficiency was 95.06 ± 0.79%.

[0076] Example 3: Preparation and characterization of an aqueous dispersion of polymer-loaded drug-eluting nanoparticles

[0077] Add 0.50g of ADEKA REASOAP ER-30 and 1.50g of ADEKA REASOAP SR-10 to 55.50g of deionized water, then add 0.94g of styrene, 22.00g of methyl methacrylate, 79.60g of butyl methacrylate and 10.20g of hydroxyethyl methacrylate, and 1.04g of n-butyl-1,2-benzisothiazolin-3-one. After blending with hydroxyethyl methacrylate, disperse the mixture in a 33% system in another bottle and stir at high speed for 3.12h to obtain stable monomer preemulsions A and H.

[0078] Prepare solution B by dissolving 0.10 g of initiator azobisisobutyramidine hydrochloride in 5.00 g of deionized water;

[0079] Prepare solution C by dissolving 0.20g sodium bicarbonate, 0.50g ADEKAREASOAP ER-30 and 1.00g ADEKA REASOAP SR-10 in 60.00g deionized water;

[0080] Prepare solution D by dissolving 0.32 g of initiator azobisisobutyramidine hydrochloride in 12.00 g of deionized water;

[0081] Prepare solution E by dissolving 0.14 g of 70% tert-butyl hydrogen peroxide aqueous solution in 2.00 g of deionized water;

[0082] Prepare solution F by dissolving 0.12g of BRUGGOLITE FF6M in 2.00g of deionized water;

[0083] Prepare solution G by dissolving 1.00g of pH adjuster dimethylethanolamine in 1.00g of deionized water.

[0084] Solution C was added to a 1L jacketed glass reactor equipped with a condenser, thermometer, and stirrer. After purging with nitrogen, the reaction temperature was raised to 85℃, and stirring was started (D=40nm, 1000rpm). 7.5% by mass of monomer preemulsion A was added as a seed to the reactor, and after stirring for 3-5 minutes, solution B was added, and stirring continued for 20-30 minutes. Then, monomer preemulsion A and solution D were added dropwise simultaneously. The remaining monomer preemulsion A was added at a uniform rate over 2 hours, followed by preemulsion H at a uniform rate over the remaining hour. Solution D was added at a uniform rate over 3 hours and 15 minutes. After the addition was complete, the reaction temperature was lowered to 65℃, and solutions E and F were added dropwise simultaneously, completing the addition over 30 minutes. After the addition was complete, the reaction temperature was lowered to 40℃, and solution G was added all at once. After stirring for 10 minutes, the pH was 8-9. The solution was then filtered through a 200-mesh filter to obtain polymer-loaded drug nanoparticle aqueous dispersion A-3. A-3 was freeze-dried using a vacuum freeze dryer to obtain freeze-dried particles A-3G.

[0085] The basic properties of the obtained polymer-loaded drug-coated nanoparticle aqueous dispersion A-3 are as follows:

[0086] The product has a milky white appearance with a bluish tint, a pH of 9.22, a yield of 93.55%, and a solids content of 43.56%.

[0087] The particle size of A-3 was analyzed using a nanoparticle size and zeta potential analyzer. The average particle size was 171.72 nm and the polydispersity index (PDI) was 0.023.

[0088] Stability analysis of A-3 was performed using a stability analyzer, and its stability index (TSI) was 0.56.

[0089] The molecular weight of A-3G was analyzed by gel permeation chromatography (GPC), and its number average molecular weight was 35016 and its weight average molecular weight was 36727.

[0090] The encapsulation efficiency of A-3G was determined by high performance liquid chromatography (HPLC), and the encapsulation efficiency was 90.81 ± 1.33%.

[0091] Example 4: Preparation and characterization of an aqueous dispersion of polymer-loaded drug-eluting nanoparticles

[0092] Add 0.50g of ADEKA REASOAP ER-30 and 1.50g of ADEKA REASOAP SR-10 to 55.50g of deionized water, then add 0.94g of styrene, 22.00g of methyl methacrylate, 79.60g of butyl methacrylate and 10.20g of hydroxyethyl methacrylate in sequence. 1.04g of iodopropynyl butylcarbamate was mixed with hydroxyethyl methacrylate and dispersed in a 33% system in another bottle. Stirring at high speed for 3.12h yielded stable monomer preemulsions A and H.

[0093] Prepare solution B by dissolving 0.10 g of initiator azobisisobutyramidine hydrochloride in 5.00 g of deionized water;

[0094] Prepare solution C by dissolving 0.20g sodium bicarbonate, 0.50g ADEKAREASOAP ER-30 and 1.00g ADEKA REASOAP SR-10 in 60.00g deionized water;

[0095] Prepare solution D by dissolving 0.32 g of initiator azobisisobutyramidine hydrochloride in 12.00 g of deionized water;

[0096] Prepare solution E by dissolving 0.14 g of 70% tert-butyl hydrogen peroxide aqueous solution in 2.00 g of deionized water;

[0097] Prepare solution F by dissolving 0.12g of BRUGGOLITE FF6M in 2.00g of deionized water;

[0098] Prepare solution G by dissolving 1.00g of pH adjuster dimethylethanolamine in 1.00g of deionized water.

[0099] Solution C was added to a 1L jacketed glass reactor equipped with a condenser, thermometer, and stirrer. After purging with nitrogen, the reaction temperature was raised to 85℃, and stirring was started (D=40mm, 1000rpm). 7.5% by mass of monomer preemulsion A was added as a seed to the reactor, and after stirring for 3-5 minutes, solution B was added, and stirring continued for 20-30 minutes. Then, monomer preemulsion A and solution D were added dropwise simultaneously. The remaining monomer preemulsion A was added at a uniform rate over 2 hours, followed by preemulsion H at a uniform rate over the remaining hour. Solution D was added at a uniform rate over 3 hours and 15 minutes. After the addition was complete, the reaction temperature was lowered to 65℃, and solutions E and F were added dropwise simultaneously, completing the addition over 30 minutes. After the addition was complete, the reaction temperature was lowered to 40℃, and solution G was added all at once. After stirring for 10 minutes, the pH was 8-9. The solution was then filtered through a 200-mesh filter to obtain polymer-loaded drug nanoparticle aqueous dispersion A-4. A-4 was freeze-dried using a vacuum freeze dryer to obtain freeze-dried particles A-4G.

[0100] The basic properties of the obtained polymer-loaded drug nanoparticle aqueous dispersion A-4 are as follows:

[0101] The product has a milky white appearance with a bluish tint, a pH of 9.53, a yield of 90.08%, and a solids content of 40.15%.

[0102] The particle size of A-4 was analyzed using a nanoparticle size and zeta potential analyzer. The average particle size was 156.06 nm and the polydispersity index (PDI) was 0.073.

[0103] Stability analysis of A-4 was performed using a stability analyzer, and its stability index (TsI) was 0.54.

[0104] The molecular weight of A-4 was analyzed by gel permeation chromatography (GPC), and its number-average molecular weight was 35329 and its weight-average molecular weight was 37136.

[0105] Example 5: Preparation and characterization of an aqueous dispersion of polymer-loaded drug-eluting nanoparticles

[0106] Add 0.50g ADEKA REASOAP ER-30 and 1.50g ADEKA REASOAP SR-10 to 55.50g deionized water, then add 0.94g styrene, 22.00g methyl methacrylate, 79.60g butyl methacrylate and 10.20g hydroxyethyl methacrylate. 1.04g 2-phenoxyethanol is mixed with hydroxyethyl methacrylate and dispersed in a 33% system in another bottle. Stir at high speed for 3-12 hours to obtain stable monomer preemulsions A and H.

[0107] Prepare solution B by dissolving 0.10 g of initiator azobisisobutyramidine hydrochloride in 5.00 g of deionized water;

[0108] Prepare solution C by dissolving 0.20g sodium bicarbonate, 0.50g ADEKAREASOAP ER-30 and 1.00g ADEKA REASOAP SR-10 in 60.00g deionized water;

[0109] Prepare solution D by dissolving 0.32 g of initiator azobisisobutyramidine hydrochloride in 12.00 g of deionized water;

[0110] Prepare solution E by dissolving 0.14 g of 70% tert-butyl hydrogen peroxide aqueous solution in 2.00 g of deionized water;

[0111] Prepare solution F by dissolving 0.12g of BRUGGOLITE FF6M in 2.00g of deionized water;

[0112] Prepare solution G by dissolving 1.00g of pH adjuster dimethylethanolamine in 1.00g of deionized water.

[0113] Solution C was added to a 1L jacketed glass reactor equipped with a condenser, thermometer, and stirrer. After purging with nitrogen, the reaction temperature was raised to 85℃, and stirring was started (D=40mm, 1000rpm). 7.5% by mass of monomer preemulsion A was added as a seed to the reactor, and after stirring for 3-5 minutes, solution B was added, and stirring continued for 20-30 minutes. Then, monomer preemulsion A and solution D were added dropwise simultaneously. The remaining monomer preemulsion A was added at a uniform rate over 2 hours, followed by preemulsion H at a uniform rate over the remaining hour. Solution D was added at a uniform rate over 3 hours and 15 minutes. After the addition was complete, the reaction temperature was lowered to 65℃, and solutions E and F were added dropwise simultaneously, completing the addition over 30 minutes. After the addition was complete, the reaction temperature was lowered to 40℃, and solution G was added all at once. After stirring for 10 minutes, the pH was 8-9. The solution was then filtered through a 200-mesh filter to obtain polymer-loaded drug nanoparticle aqueous dispersion A-5. A-5 was freeze-dried using a vacuum freeze dryer to obtain freeze-dried particles A-5G.

[0114] The basic properties of the obtained polymer-loaded drug-coated nanoparticle aqueous dispersion A-5 are as follows:

[0115] The product has a milky white appearance with a bluish tint, a pH of 9.36, a yield of 91.48%, and a solids content of 40.97%.

[0116] The particle size of A-5 was analyzed using a nanoparticle size and zeta potential analyzer. The average particle size was 145.37 nm and the polydispersity index (PDI) was 0.046.

[0117] Stability analysis of A-5 was performed using a stability analyzer, and its stability index (TSI) was 0.58.

[0118] The molecular weight of A-5G was analyzed by gel permeation chromatography (GPC), and its number-average molecular weight was 35974 and its weight-average molecular weight was 37077.

[0119] Example 6: Preparation and characterization of an aqueous dispersion of polymer-loaded drug-eluting nanoparticles

[0120] Add 0.50g of ADEKA REASOAP ER-30 and 1.50g of ADEKA REASOAP SR-10 to 55.50g of deionized water, then add 0.94g of styrene, 22.00g of methyl methacrylate, 79.60g of butyl methacrylate and 10.20g of hydroxyethyl methacrylate. 1.04g of ethylparaben is blended with hydroxyethyl methacrylate and dispersed in a 33% system in another bottle. Stir at high speed for 3-12 hours to obtain stable monomer preemulsions A and H.

[0121] Prepare solution B by dissolving 0.10 g of initiator azobisisobutyramidine hydrochloride in 5.00 g of deionized water;

[0122] Prepare solution C by dissolving 0.20g sodium bicarbonate, 0.50g ADEKAREASOAP ER-30 and 1.00g ADEKA REASOAP SR-10 in 60.00g deionized water;

[0123] Prepare solution D by dissolving 0.32 g of initiator azobisisobutyramidine hydrochloride in 12.00 g of deionized water;

[0124] Prepare solution E by dissolving 0.14 g of 70% tert-butyl hydrogen peroxide aqueous solution in 2.00 g of deionized water;

[0125] Prepare solution F by dissolving 0.12g of BRUGGOLITE FF6M in 2.00g of deionized water;

[0126] Prepare solution G by dissolving 1.00g of pH adjuster dimethylethanolamine in 1.00g of deionized water.

[0127] Solution C was added to a 1L jacketed glass reactor equipped with a condenser, thermometer, and stirrer. After purging with nitrogen, the reaction temperature was raised to 85℃, and stirring was started (D=40mm, 1000rpm). 7.5% by mass of monomer preemulsion A was added as a seed to the reactor, and after stirring for 3-5 minutes, solution B was added, and stirring continued for 20-30 minutes. Then, monomer preemulsion A and solution D were added dropwise simultaneously. The remaining monomer preemulsion A was added at a uniform rate over 2 hours, followed by preemulsion H at a uniform rate over the remaining hour. Solution D was added at a uniform rate over 3 hours and 15 minutes. After the addition was complete, the reaction temperature was lowered to 65℃, and solutions E and F were added dropwise simultaneously, completing the addition over 30 minutes. After the addition was complete, the reaction temperature was lowered to 40℃, and solution G was added all at once. After stirring for 10 minutes, the pH was 8-9. The solution was then filtered through a 200-mesh filter to obtain polymer-loaded drug nanoparticle aqueous dispersion A-6. A-6 was freeze-dried using a vacuum freeze dryer to obtain freeze-dried particles A-6G.

[0128] The basic properties of the obtained polymer-loaded drug nanoparticle aqueous dispersion A-6 are as follows:

[0129] The product has a milky white appearance with a bluish tint, a pH of 9.31, a yield of 92.70%, and a solids content of 42.46%.

[0130] The particle size of A-6 was analyzed using a nanoparticle size and zeta potential analyzer. The average particle size was 140.80 nm and the polydispersity index (PDI) was 0.032.

[0131] Stability analysis of A-6 was performed using a stability analyzer, and its stability index (TsI) was 0.61.

[0132] The molecular weight of A-6G was analyzed by gel permeation chromatography (GPC), and its number-average molecular weight was 36,632 and its weight-average molecular weight was 37,774.

[0133] Example 7: Preparation and Performance Testing of Functional Coatings and Surface Film Materials

[0134] Weigh 10g of polymer nanoparticle aqueous dispersion A-3 and place it in a flask. Add 10g of deionized water at a mass ratio of 1:1 for dilution and dispersion. Then add 1g of crosslinking agent Aquolin 268, 0.3g of film-forming aid dipropylene glycol monomethyl ether, 0.3g of wetting and leveling agents BYK-333 and BYK346, and 0.03g of defoamer Tego Airex 902W. Stir with a magnetic stirrer at 800rpm for 10min to ensure thorough dispersion. Weigh 1g and drop it onto the substrate surface. Then, use a wet film coater to horizontally coat the surfaces of nylon cloth, glass plate, engineering plastic alloy plate (ABS+PC), thermoplastic polyester plate (PET), and carbon fiber plate. Let it stand until the moisture evaporates to obtain surface film materials B-1, B-2, B-3, B-4, and B-5.

[0135] Hardness tests were conducted on materials B-1 to B-4 using the pencil scratch test. A dried material board was placed on a horizontal table. During the experiment, a pencil was fixed inside the instrument, pressing it downwards at a 45° angle onto the material surface. The instrument was moved to allow the pencil to scratch the surface, advancing 8 mm at a speed of 1 mm / s. After 30 seconds, the surface was observed for scratches or damage. If defects of 3 mm or more appeared, the pencil hardness was reduced, and the same method was repeated. If no defects appeared, the pencil hardness was increased, and the experiment continued until defects smaller than 3 mm appeared. The hardness of the material was represented by the highest pencil hardness that did not cause scratches or damage exceeding 3 mm on the material surface.

[0136] Table 1. Results of Pencil Scratch Test for Hardness

[0137]

[0138] After the material was formed, its hardness was tested using the pencil scratch method. The experiment could be conducted on the surfaces of all substrates except nylon fabric. Experimental results showed that the slow-release antibacterial surface film material could form a film structure with a certain hardness after forming on substrates such as glass, ABS+PC, PET, and carbon fiber, with hardness levels all above HB. Simultaneously, a continuous film structure could also be formed on the nylon fabric surface.

[0139] Chemical resistance tests were conducted on grades B-1 to B-5. The chemical resistance test method is shown below:

[0140] Water resistance: The test solution is distilled water. The test area is the middle part of each plate. Absorbent paper is placed on the test area, and a glass cover is used to seal it. The filter paper is kept moist during the experiment. The test time is 24 hours, and the plate is observed after 24 hours of rest.

[0141] Alkali resistance: The test solution is a 10% Na2CO3 solution. The test area is the middle part of each plate. Absorbent paper is placed on the test area, and a glass cover is used to seal it. The filter paper is kept moist during the experiment. The experiment lasts for 24 hours, and observation is performed 24 hours after the experiment.

[0142] Alcohol resistance: The test solution is a 50% (volume fraction) ethanol solution. The test area is the middle part of each plate. Absorbent paper is placed on the test area, and a glass cover is used for sealing. The filter paper is kept moist during the experiment. The experiment lasts for 24 hours, and observation is performed 24 hours after the experiment.

[0143] Acid resistance: The test solution is a 10% acetic acid solution. The test area is the middle part of each plate. Absorbent paper is placed on the test area, and a glass cover is used to seal it. The filter paper is kept moist during the experiment. The experiment lasts for 24 hours, and observation is performed 24 hours after the experiment.

[0144] Table 2. Grading and Evaluation of Chemical Resistance

[0145]

[0146]

[0147] The results of the chemical resistance test are attached. Figure 1 As shown in Table 3 below, the surface film materials prepared using the above-mentioned polymer-loaded drug nanoparticles exhibit good resistance to water, alcohol, acid, and alkali on various substrate surfaces, based on the resistance test results.

[0148] Table 3 Results of the chemical-resistant bear test

[0149]

[0150] Example 8: Monitoring of the film formation process of surface film materials

[0151] Weigh 10g of polymer nanoparticle aqueous dispersion A-3 and place it in a flask. Add 10g of deionized water at a mass ratio of 1:1 for dispersion. Then add 1g of crosslinking agent Aquolin 268, 0.3g of film-forming aid dipropylene glycol monomethyl ether, 0.3g of wetting and leveling agents BYK-333 and BYK-346, and 0.03g of defoamer TegoAirex 902W. Stir with a magnetic stirrer at 800rpm for 10min to ensure thorough dispersion. Weigh 1g and drop it onto the substrate surface. Then use a wet film coater to horizontally coat the glass plate surface. After the water evaporates, the surface film material B-6 is obtained.

[0152] The precursor material was dropped onto the probe surface of an attenuated total reflectance-Fourier transform infrared spectrometer for experiments. Infrared spectra were acquired at a rate of 10 min / acquisition for the first 12 hours, followed by acquisitions at a rate of 1 h / acquisition for the remaining hours. The characteristic peaks of the isocyanate group (2275-2250 cm⁻¹) were analyzed after acquisition. -1 1400-1350cm -1 By comparing and analyzing the results, a curve showing the change in isocyanate groups during the film-forming process was plotted to investigate the film-forming effect of the cross-linked film. The results are attached. Figure 2 As shown, the isocyanate groups were continuously consumed over three days. In the initial 10 hours, the reaction was rapid, with the residual isocyanate content quickly dropping below 40%, after which the reaction rate gradually slowed. After three days, the reaction was essentially complete, with the residual isocyanate group content less than 1%. These results indicate that further reaction after curing allows the material to form a more dense structure; the low residual isocyanate content reduces the material's potential toxicity, demonstrating the feasibility of the material molding process.

[0153] Example 9: Preparation and application of surface film materials on various substrates and evaluation of their biosafety

[0154] Weigh 10g of polymer nanoparticle aqueous dispersion A-3 and place it in a flask. Add 10g of deionized water (1:1 by mass) for dilution and dispersion. Then add 1g of crosslinking agent Aquolin 268, 0.3g of film-forming aid dipropylene glycol monomethyl ether, 0.3g of wetting and leveling agents BYK-333 and BYK346, and 0.03g of defoamer TegoAirex 902W. Stir at 800rpm for 10 minutes using a magnetic stirrer to ensure thorough dispersion. Weigh 1g and drop it onto the substrate surface. Then, use a wet film coater to horizontally coat the surfaces of nylon cloth, glass plate, engineering plastic alloy plate (ABs+PC), thermoplastic polyester plate (PET), and carbon fiber plate. Allow to stand until the moisture evaporates to obtain surface film materials B-7, B-8, B-9, B-10, and B-11, as shown in the attached figure. Figure 3 As shown.

[0155] The material can form a transparent hard film on the surface of five substrates, and after physical and chemical performance testing, it has been preliminarily proven that it has certain application value on the surface of most environmental instruments and building materials.

[0156] To determine potential residual impurities in sustained-release antibacterial surface membrane materials, membrane material B-7 was immersed in a beaker containing 2000 mL of deionized water using a dialysis bag at 25°C, with stirring at 500 rpm. The immersion solution was collected on day 7. Residual substances in the dialysis solution were determined using HPLC. Samples with potential residues were tested using HPLC, and peak shapes and positions were compared to calculate the residual amounts, thus providing a preliminary assessment of the biosafety of the sustained-release antibacterial material. Chromatographic column: C10. 18 MP(2), 4.6×250mm, 5μm; mobile phase: acetonitrile-water (90:10, v / v) gradient to 50:50; detection wavelength: 240nm / 224nm; flow rate: 0.8mL / min; column temperature: 35℃; injection volume: 20μL.

[0157] The results of the biosafety test are attached below. Figure 4 And as shown in Table 4:

[0158] Table 4. Detection results of leachable matter in the materials.

[0159]

[0160]

[0161] The crosslinking agent blended in the precursor material exhibited a residue rate of <1% after complete curing within three days. Simultaneously, the addition amounts of film-forming aids were all low, and no excessive dissolution of other film-forming aids was observed during testing. Residual monomers and reactive surfactants from the polymer nanoparticle polymerization process showed slight dissolution after 7 days of immersion. (1cm) 2 The material has a leachable content of <0.04% in water, and the actual dissolution of monomeric substances within the material is at a low level. Example 9 further demonstrates that the residual amounts of various monomers and reactive surfactants within the material are all at low levels. This preliminarily demonstrates that the material possesses a certain degree of biocompatibility.

[0162] Example 10: Preparation of surface film materials on various substrates and testing of their sustained-release antibacterial properties

[0163] Weigh 10g of polymer nanoparticle aqueous dispersion A-3 and place it in a flask. Add 10g of deionized water at a mass ratio of 1:1 for dilution and dispersion. Then add 1g of crosslinking agent Aquolin268, 0.3g of film-forming aid dipropylene glycol monomethyl ether, 0.3g of wetting and leveling agents BYK-333 and BYK346, and 0.03g of defoamer Tego Airex 902W. Stir with a magnetic stirrer at 800rpm for 10min to ensure thorough dispersion. Weigh 1g and drop it onto the substrate surface. Then, use a wet film coater to horizontally coat the surfaces of nylon cloth, glass plate, engineering plastic alloy plate (ABS+PC), thermoplastic polyester plate (PET), and carbon fiber plate. Let it stand until the moisture evaporates to obtain surface film materials B-12, B-13, B-14, B-15, and B-16.

[0164] (1) Antifungal performance test:

[0165] Antibacterial tests were conducted according to the standards for antibacterial and mildew-resistant wood decorative panels (JC / T 2039-2010) and the test method for mildew resistance of paint films (GB / T 1741-2020).

[0166] (a) The antifungal properties of surface film materials B-12, B-13, B-14, B-15, and B-16 were tested using *Aspergillus brasiliensis* (ATCC 16404), *Aspergillus niger* (CMCC 98003), *Penicillium citrinum* (ATCC 1109), *Penicillium funiculosum* (CGMCC 3.3875), and *Mucor racemosus* (GDMCC 3.87) as experimental strains. The preserved strains were transferred to PDA slant agar and cultured at 28°C for 12 days. Once a distinct mold layer appeared on the surface and a large number of spores were generated, the materials were removed for use.

[0167] (b) Add a small amount of sterile water to the culture slant medium after incubation. Gently scrape off the surface mold spores with an inoculation needle and transfer them to an Erlenmeyer flask. Add approximately 50 mL of 0.05% Tween 80 physiological saline solution. Add 10-15 glass beads with a diameter of 5 mm to the Erlenmeyer flask and gently shake for 15 min. Then, plug the glass funnel with absorbent cotton, filter, count and observe the cells under a microscope using a hemocytometer, and store for later use.

[0168] (c) Add 15 mL of nutrient agar medium to a sterile petri dish (90 mm in diameter) and allow it to solidify before use. Place the blank control sample and the test sample separately on the medium. Then, inoculate 1 mL of spore suspension into the 15 mL nutrient agar medium, mix well, and pour this mixture onto the test sample and substrate surfaces. Incubate at 28°C and 92% RH. Perform three replicates for each type of test sample.

[0169] (d) Place the sterile filter paper of the negative control sample on a plate culture medium and proceed as in step 4 above. After incubation for 7 days under the same conditions, there should be obvious bacterial growth on the filter paper; otherwise, the test should be considered invalid.

[0170] (e) After 28 days, observe the growth of surface mold and record the experimental results.

[0171] The results of the antifungal test are attached. Figure 5 And as shown in Table 5:

[0172] Table 5 Evaluation of Antifungal Test Results

[0173]

[0174]

[0175] In the negative control group, the filter paper surfaces all showed varying degrees of growth, with different dominant bacterial strains present inside each of the three plates. A large amount of mold layer formed on the filter paper surface, covering more than 70% of the total surface area, reaching a severe growth level. The five blank control surfaces—nylon cloth, glass plate, engineering plastic alloy plate (ABS+PC), thermoplastic polyester plate (PET), and carbon fiber plate—all showed some mold growth, with obvious colonies appearing at the edges and interiors, covering more than 10% of the surface area of ​​the blank control materials, indicating a level 2 or 3 mold growth condition. In contrast, over 90% of the surface area of ​​the experimental group material showed no mold growth, with mold colonies appearing only at some material edges; simultaneously, mold growth at the outer edges was also somewhat inhibited, essentially reaching a level 0 or 1 mold growth condition. The experimental results indicate that the material prepared in this experiment has a good anti-mold effect, effectively inhibiting common molds in the environment. Even after one month of curing and storage, the material still exhibits excellent antibacterial ability, preliminarily demonstrating that the antibacterial surface material has a certain slow-release antibacterial effect.

[0176] (2) Antibacterial performance test:

[0177] The environments in which medical devices and building materials are used harbor a wide variety of microorganisms. Therefore, mixed culture can effectively simulate everyday application environments. Mixing *Escherichia coli* and *Staphylococcus aureus* can simulate real-life co-infections of microorganisms, helping to understand their interactions in a shared environment and their impact on the host. This experiment followed the test method for antibacterial properties of plastics and plastic surfaces (GB / T 31402-2015). Antibacterial properties of surface film materials B-12, B-13, B-14, B-15, and B-16 were tested using a mixed culture method.

[0178] (a) Bacterial pre-culture: Escherichia coli (ATCC 6538) and Staphylococcus aureus (ATCC 9739) were used as experimental strains to test their antifungal properties. The preserved strains were transferred to slant agar and incubated at 35°C for 24 h.

[0179] (b) Prepare 12 samples, including slow-release antibacterial surface film materials attached to different substrates and untreated materials.

[0180] (c) Prepare the inoculum by transferring the pre-cultured bacteria into 1 / 500 NB culture medium and diluting it to a bacterial concentration of 2.5 × 10⁻⁶. 5 CFU / mL - 10×10 5 Between CFU / mL.

[0181] (d) Inoculate the sample: Place the sample in a sterile petri dish, drop the inoculation solution onto the sample surface, cover with a thin film and gently press to spread the bacterial solution, then incubate at 35°C and 95% relative humidity for 24 hours. Afterwards, recover the bacteria. For inoculated samples that have not undergone antimicrobial treatment, recover the bacterial strain, and thoroughly rinse the sample.

[0182] (e) To test the viable count, count the viable bacteria on the sample after culturing according to the procedure. The viable count was determined using the plate culture method. The recovered solution was serially diluted 10-fold and placed in sterile petri dishes, and then incubated at 35°C for 48 hours.

[0183] (f) Statistical results: Count the colonies with a count between 30 and 300, record the colony count on each dilution petri dish and retain 2 significant figures, and record the dilution factor. Calculate the viable count according to formula (1).

[0184]

[0185] In the formula:

[0186] N-sample per em 2The number of viable bacteria;

[0187] C - The average number of viable bacteria on the surfaces of the two culture media;

[0188] D - Dilution factor;

[0189] V - SCDLP medium used for the elution operation, mL;

[0190] A - The membrane surface area covering the material surface, mm 2 .

[0191] Calculate the geometric mean of the recovered viable bacteria count for each group of specimens and retain 2 significant figures. If there are no colonies on all agar plates at a certain dilution factor, record the viable bacteria as <V (the volume of SCDLP culture solution used for elution, mL). When calculating the average, if there are no bacteria counts at all dilution degrees, record it as V. For example: V = 10 mL, and the calculated average bacteria count is 10.

[0192] (g) Calculation of antibacterial performance: When the test is considered effective, calculate the antibacterial performance value using formula (2).

[0193] R = (U t - U0) - (A - U0) = U t - A Formula (2)

[0194] In the formula:

[0195] R - Antibacterial performance value;

[0196] U0 - The logarithmic mean value of the bacteria count immediately after inoculation of the specimen without antibacterial treatment, CFU / cm 2 ;

[0197] U t - The logarithmic mean value of the bacteria count 24 h after inoculation of the specimen without antibacterial treatment, CFU / cm 2 ;

[0198] A - The logarithmic mean value of the bacteria count 24 h after inoculation of the specimen with antibacterial treatment, CFU / cm 2 .

[0199] The results of the antibacterial performance test are as follows:

[0200] Appendix Figure 6 shows the plate count culture results at a dilution factor of 1-fold. Among them, the golden colonies are Staphylococcus aureus, and the white colonies are Escherichia coli. At the same gradient, there is almost no bacterial growth in the test group, while there is obvious growth of Staphylococcus aureus and Escherichia coli in the blank control group.

[0201] Table 6 Antibacterial performance value

[0202]

[0203] The antibacterial performance value was calculated based on the actual viable bacteria count, and the results are shown in Table 6. A higher antibacterial performance value indicates stronger antibacterial performance. The sustained-release antibacterial surface film material exhibited excellent antibacterial effects after coating on five different substrates, and the experiments showed good parallelism. The surface material, even after being stored for one month, still maintained excellent antibacterial effects, further demonstrating its good sustained-release antibacterial capability.

[0204] (3) Sustained-release performance test:

[0205] For antibacterial surface materials coated on medical devices to have a long-lasting effect, testing their sustained-release effect is crucial. Water is indispensable during device use, and device surfaces are frequently wiped with water. Therefore, investigating the drug diffusion effect of materials in water can indirectly confirm their sustained-release capability. At room temperature (25℃), the surface membrane material B-13 was immersed in a beaker containing 2000 mL of deionized water using a dialysis bag, with stirring at 500 rpm. The immersion solution was removed at 0.5h, 1h, 2h, 3h, 4h, 8h, 16h, 24h, 36h, 48h, 72h, 4 days, 5 days, 6 days, and 7 days, and the dialysis solution was replaced periodically. The drug concentration in the immersion solution was tested using high-performance liquid chromatography (HPLC), and a sustained-release effect curve was constructed to investigate the sustained-release effect. The experiment was repeated three times, and the average value of the results was taken. The cumulative drug release was calculated using the following formula:

[0206]

[0207] In the formula:

[0208] E r - Cumulative drug release;

[0209] V e - The volume of water replaced, in mL;

[0210] V0 - Total volume of the release medium, mL;

[0211] C i - The concentration of the released liquid during the i-th displacement sampling;

[0212] m drug -Total mass of drug carried by nanoparticles;

[0213] n - the number of times water is replaced.

[0214] Drug retention rate was determined using a 7-day water dialysis method, and the results are attached. Figure 7As shown, the drug is slowly released over 7 days. Initially, the release rate is relatively fast, and the drug retention rate drops below 90% within 2 days. Subsequently, the release rate gradually decreases, and after 7 days, the drug retention rate is 74.68%. This preliminarily demonstrates that it has a certain sustained-release effect in the environment.

[0215] This embodiment characterizes the antibacterial and sustained-release properties of surface film materials on various substrates, demonstrating that the antibacterial drugs coated on the materials can be largely retained within 7 days, and still have excellent antibacterial and antifungal capabilities after 30 days.

Claims

1.A polymer drug-loaded nanoparticle aqueous dispersion, characterized in that: water is used as the dispersion medium; the reaction monomers are styrene, methyl methacrylate, butyl methacrylate and hydroxyethyl methacrylate; a reactive surfactant is used as the surfactant; azobisisobutyronitrile or azobisisformamide hydrochloride is used as the initiator; an emulsion polymerization is used to obtain the polymer drug-loaded nanoparticle aqueous dispersion; and the following raw materials are used in the following mass percentages: 0.2-0.8% of styrene, 7-12% of methyl methacrylate, 30-35% of butyl methacrylate, 2-7% of hydroxyethyl methacrylate, 0.1-0.6% of the antibacterial drug, 0.5-1.2% of the initiator, 2-3% of the surfactant, 0.2-0.5% of sodium bicarbonate, 0.01-0.03% of the oxidation-reduction system, 0.01-0.03% of the pH regulator, and the balance being deionized water, with the total mass percentage being 100%; the log P value of the antibacterial drug loaded on the nanoparticles is 0.5-6, including n-butyl-1,2-benzisothiazolin-3-ketone (CAS 4299-07-4), iodoallyl alcohol butyl carbamate (CAS 55406-53-6), 2-phenoxyethanol (CAS 122-99-6) or nipagin ethyl (CAS 120-47-8), and the antibacterial drug is loaded on the polymer nanoparticles during the polymerization process. 2.A preparation method of the polymer drug-loaded nanoparticle aqueous dispersion according to claim 1, characterized in that: a solution is prepared by adding part of the emulsifier into water, sequentially adding the monomers and the antibacterial drug, and stirring at 600 rpm for 3-12 h to obtain a stable monomer pre-emulsion A; part of the initiator is dissolved in deionized water to obtain a solution B with a mass concentration of 3-5%; sodium bicarbonate and part of the emulsifier are dissolved in deionized water to obtain a solution C; part of the initiator is dissolved in deionized water to obtain a solution D with a mass concentration of 2-3%; an oxidizing agent is dissolved in deionized water to obtain a solution E with a mass concentration of 4-6%; a reducing agent is dissolved in deionized water to obtain a solution F with a mass concentration of 4-6%; and a pH regulator is dissolved in deionized water to obtain a solution G with a mass concentration of 50%; and the reaction process is as follows: solution C is added into a 1L jacketed glass reaction kettle equipped with a condenser, a thermometer and a stirring paddle, the temperature is raised to 85℃ after nitrogen replacement, and stirring is started; 5% of the monomer pre-emulsion A is taken as a seed and added into the reaction kettle, stirring is performed for 3-5 min, and then solution B is added; stirring is continuously performed for 20-30 min; then, the monomer pre-emulsion A and solution D are simultaneously added dropwise, the remaining monomer pre-emulsion A is added at a uniform speed within 3 h; solution D is added at a uniform speed within 3 h and 15 min; after the dropwise addition is completed, the temperature is lowered to 65℃, and solutions E and F are simultaneously added dropwise within 30 min; after the dropwise addition is completed, the temperature is lowered to 40℃, solution G is added at one time, and stirring is performed for 10 min, after which the pH value is 8-9, and the polymer drug-loaded nanoparticle aqueous dispersion is obtained by passing through a 200-mesh filter. ​ ​ ​ ​ ​ ​ ​ ​ 3. The use of the polymer drug-loaded nanoparticle aqueous dispersion of claim 1 in antibacterial coatings. The polymer drug-loaded nanoparticle aqueous dispersion of claim 1 is used as the main body of the formula, mixed with alcohol ether film-forming additives, wetting and leveling agents, and defoaming agents to form antibacterial coatings, which are used in combination with a crosslinking agent (2,4,6-trioxotriazine-1,3,5(2H,4H,6H)-triyl) tris(hexamethylene) isocyanate. The antibacterial coatings are suitable for substrates such as wood, nylon cloth, glass plates, engineering plastic alloy plates, thermoplastic polyester plates, and carbon fiber plates.

Images