| dc.description.abstract | 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. | en_US |
