包载荧光共轭聚合物的阳离子聚合物纳米微球的合成及协同抗菌效果研究

Synthesis and Synergistic Antibacterial Activity of Cationic Polymer Fluorescent Nanoparticles Loaded with Fluorescent Conjugated Polymer

由于耐药菌感染问题的日益严重,寻求新的抗菌策略,发展更为有效的抗菌材料成为人们迫切需要解决的重要任务。本工作提供了一种结合阳离子和光动力抗菌机理的协同抗菌新方式,以N-异丙基丙烯酰胺(NIPAM)和甲基丙烯酰氧乙基三甲基氯化铵(DMC)为单体,通过微乳液聚合的方法制备了包载有荧光共轭聚合物(FCP)的阳离子荧光纳米微球,分析了微球的组成、粒径分布以及微观形貌等,并检测了其产生单线态氧的能力。对大肠杆菌(E.coli)、金黄色葡萄球菌(S.aureus)和耐甲氧西林金黄色葡萄球菌(MRSA)的抗菌实验结果表明:在微球质量浓度较高(≥0.05 mg/mL)时以阳离子抗菌机理为主导,在质量浓度较低(≤0.01 mg/mL)时,光动力抗菌机理能够有效提高微球的抗菌能力;m(NIPAM)∶m(DMC)=1∶3的微球在质量浓度为0.01 mg/mL时,经过30 min光照培养后对E.coli和S.aureus的协同灭菌率均能达到95%以上;而m(NIPAM)∶m(DMC)=1∶1的微球在质量浓度为0.05 mg/mL时对MRSA的协同灭菌率最高。与人类细胞共培养实验表明该纳米微球在质量浓度低于0.1 mg/mL时具有良好的生物相容性。因此,该荧光纳米微球能有效结合阳离子和光动力抗菌功能,发挥优良的抗菌能力,有望为耐药菌感染问题的解决提供支持。

As drug-resistant bacteria infection become increasingly serious recently,pursuing new antibacterial strategies and developing more effective antibacterial materials have become an important task.This work provided a new antibacterial method combining photodynamic and cationic antibacterial mechanism.The fluorescent nanospheres were successfully prepared by microemulsion polymerization using N-isopropylacrylamide(NIPAM)and methylacryloyloxyethyltrimethyl ammonium chloride(DMC)as monomers,loaded with a fluorescent conjugated polymer(FCP).The composition,particle size distribution and micro-morphology of the microspheres were analyzed,and their ability to produce singlet oxygen was tested.The fluorescent nanospheres were used to study the antibacterial activity of E.coli,S.aureus and methicillin resistant Staphylococcus aureus(MRSA).The results indicated that the cationic antibacterial mechanism was dominated when the mass concentration of nanospheres was high(≥0.05 mg/mL).When the mass concentration was low(≤0.01 mg/mL),photodynamic antibacteria activity contributed primarily to the total antibacterial ability of nanospheres.For the nanospheres with m(NIPAM)∶m(DMC)=1∶3,the sterilization rate of both E.coli and S.aureus reached over 95%after 30 min of illumination when the concentration of nanospheres was 0.01 mg/mL.For the nanospheres with m(NIPAM)∶m(DMC)=1∶1,the synergistic sterilization rate of MRSA was the highest when the concentration of nanospheres was 0.05 mg/mL.Cytotoxicity assay showed that the nanospheres had good biocompatibility when the mass concentration was lower than 0.1 mg/mL.Therefore,the fluorescent nanospheres can effectively combine cationic and photodynamic antibacterial functions,develop an excellent synergistic antibacterial ability,and are expected to provide support for the solution to the drug-resistant bacterial infection.