نفیسه دعوتی

The objective of this study was to in-vitro investigation of antimicrobial activity effect of nano-ZnO loaded nanoliposomes at different level of lecithin: nano-ZnO ratio (5:1, 15:1, and 25:1 w/w) against Escherichia coli (ATCC 2592) and Staphylococcus aureus (ATCC 25923). Nano-ZnO loaded nanoliposomes were prepared through thin layer hydration sonication and heat methods. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of nano-ZnO loaded nanoliposomes and free nano-ZnO against Escherichia coli and Staphylococcus aureus were determined and their antimicrobial activities were evaluated by time- kill curve analysis. Results showed that the encapsulation of nano-ZnO in nanoliposome systems significantly increased antimicrobial activities of them by increasing their penetration into the microbial cell. Nano-ZnO loaded nanoliposomes were prepared through thin layer hydration showed higher antimicrobial activity compared to those prepared by heat method. From the time- kill curves, the log phase growth of Escherichia coli (8 hours) and Staphylococcus aureus (7 hours) in the medium containing nano-ZnO loaded nanoliposomes prepared through the thin layer hydration sonication at the highest level of lecithin: nano-ZnO ratio (25:1 w/w) at MIC and MBC values decreased to 5 and 4 hours and to 2 and less than 1 hours, respectively.