a University of Cambridge , Cambridge , UK.
Int J Environ Health Res. 2013;23(5):407-18. doi: 10.1080/09603123.2012.743115. Epub 2013 Apr 5.
This research aimed to investigate in vitro photocatalytic bactericidal effect of Ag-TiO2 nanocomposite using Escherichia coli as a model organism. Highly dispersed, Ag-TiO2 nanocomposite is used with an average particle size of less than 20 nm. Bactericidal analysis was carried out in Luria Bertani medium on solid agar plates with various illumination time and different concentrations of Ag-TiO2 nanocomposite. Transmission electron microscopic analysis of bacterial section was used to detect the effect of irradiation of Ag-TiO2 nanocomposite on the ultra structure of the bacterial cell in order to reveal possible cellular damage. The mechanism underlying the action of photoexcited Ag-TiO2 nanocomposite on E. coli cell membrane is also evaluated. The results confirmed that E. coli cells after the contact with Ag-TiO2 nanocomposite were damaged since they showed membrane disorganization. This causes the enhanced level of membrane permeability leading to the build-up of Ag-TiO2 nanocomposite in the bacterial membrane and also cellular internalization of these nanoparticles.
本研究旨在利用大肠杆菌作为模型生物，研究 Ag-TiO2 纳米复合材料的体外光催化杀菌效果。使用高度分散的、平均粒径小于 20nm 的 Ag-TiO2 纳米复合材料。在含有不同浓度 Ag-TiO2 纳米复合材料的 LB 培养基固体琼脂平板上，通过不同的光照时间进行杀菌分析。利用细菌切片的透射电子显微镜分析来检测 Ag-TiO2 纳米复合材料对细菌细胞超微结构的照射效果，以揭示可能的细胞损伤。还评估了光激发 Ag-TiO2 纳米复合材料对大肠杆菌细胞膜作用的机制。结果证实，与 Ag-TiO2 纳米复合材料接触后的大肠杆菌细胞受到了损伤，因为它们的细胞膜出现了紊乱。这导致了膜通透性的增强，使得 Ag-TiO2 纳米复合材料在细菌膜中积累，并导致这些纳米颗粒的细胞内内化。
