Analytical Chemistry Laboratory, Department of Chemistry, Indian Institute of Technology, Roorkee 247667, India.
Colloids Surf B Biointerfaces. 2012 Jun 1;94:143-50. doi: 10.1016/j.colsurfb.2012.01.046. Epub 2012 Feb 7.
Recent studies indicated the role of ROS toward antibacterial activity. In our study we report ROS mediated membrane lipid oxidation of Escherichia coli treated with ZnO nanoparticles (NPs) as supported by detection and spectrophotometric measurement of malondialdehyde (MDA) by TBARS (thiobarbituric acid-reactive species) assay. The antibacterial effects of ZnO NPs were studied by measuring the growth curve of E. coli, which showed concentration dependent bacteriostatic and bacteriocidal effects of ZnO NPs. The antibacterial effects were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Further, antibacterial effect of ZnO NPs was found to decrease by introducing histidine to the culture medium treated with ZnO NPs. The ROS scavenging action of histidine was confirmed by treating histidine to the batch of Escherichia coli+ZnO NPs at the end of the lag phase of the growth curve (Set-I) and during inoculation (Set-II). A moderate bacteriostatic effect (lag in the E. coli growth) was observed in Set-II batch while Set-I showed no bacteriostatic effect. From these evidences we confirmed that the antibacterial effect of bare as well as TG capped ZnO NPs were due to membrane lipid peroxidation caused by the ROS generated during ZnO NPs interaction in culture medium.
最近的研究表明，活性氧（ROS）在抗菌活性中发挥作用。在我们的研究中，我们报告了 ROS 介导的大肠杆菌细胞膜脂质氧化，这是通过 TBARS（硫代巴比妥酸反应性物质）测定法检测和分光光度法测量丙二醛（MDA）来支持的。通过测量大肠杆菌的生长曲线研究了 ZnO NPs 的抗菌作用，结果表明 ZnO NPs 具有浓度依赖性的抑菌和杀菌作用。通过扫描电子显微镜（SEM）和透射电子显微镜（TEM）对其抗菌作用进行了表征。此外，通过向用 ZnO NPs 处理的培养基中引入组氨酸，发现 ZnO NPs 的抗菌作用降低。通过在生长曲线的迟滞期结束时（Set-I）和接种时（Set-II）将组氨酸添加到大肠杆菌+ZnO NPs 批次中，证实了组氨酸的 ROS 清除作用。在 Set-II 批次中观察到适度的抑菌作用（大肠杆菌生长的迟滞），而 Set-I 批次则没有抑菌作用。从这些证据中，我们证实了裸露和 TG 封端的 ZnO NPs 的抗菌作用是由于在培养基中 ZnO NPs 相互作用过程中产生的 ROS 引起的细胞膜脂质过氧化。
