Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK.
Nanotoxicology. 2012 Dec;6:857-66. doi: 10.3109/17435390.2011.626532. Epub 2011 Oct 18.
This study investigated the dissolution-based toxicity mechanism for silver nanoparticles to Escherichia coli K12. The silver nanoparticles, synthesised in the vapour phase, are effective anti-bacterial agents against the Gram-negative bacterium, E. coli K12. The nanoparticles associate with the bacterial cell wall, appearing to interact with the outer and inner membranes, and then dissolve to release Ag(+) into the cell and affect a transcriptional response. The dissolution of these nanoparticles in a modified LB medium was measured by inductively coupled plasma mass spectrometry (ICP-MS) and has been shown to follow a simple first-order dissolution process proportional to the decreasing surface area of the nanoparticles. However, the resulting solution phase concentration of Ag(+), demonstrated by the ICP-MS data, is not sufficient to cause the observed effects, including inhibition of bacterial growth and the differential expression of Cu(+) stress response genes. These data indicate that dissolution at the cell membrane is the primary mechanism of action of silver nanoparticles, and the Ag(+) concentration released into the bulk solution phase has only limited anti-bacterial efficacy.
本研究调查了基于溶解的银纳米颗粒对大肠杆菌 K12 的毒性机制。气相合成的银纳米颗粒是革兰氏阴性菌大肠杆菌 K12 的有效抗菌剂。这些纳米颗粒与细菌细胞壁结合，似乎与外膜和内膜相互作用，然后溶解释放出 Ag(+)进入细胞，并影响转录反应。通过电感耦合等离子体质谱法 (ICP-MS) 测量了这些纳米颗粒在改良 LB 培养基中的溶解情况，结果表明，溶解遵循简单的一级溶解过程，与纳米颗粒的表面积成比例减少。然而，由 ICP-MS 数据表明的溶液相中 Ag(+)的浓度不足以引起观察到的效果，包括抑制细菌生长和铜（Cu(+)）应激反应基因的差异表达。这些数据表明，细胞膜的溶解是银纳米颗粒的主要作用机制，释放到体相溶液中的 Ag(+)浓度对其抗菌效果具有一定的限制。
