Nano-materials can be damaging to cells, mainly due to damage to cell membranes and the induction of oxidative stress as discussed in previous reports . The excessive accumulation of reactive oxygen species (ROS) can damage the cell membrane and reduce its stability. In this regard, lactate dehydrogenase (LDH) is a vital indicator which can be used as a proxy for oxidative damage to the cell membrane . Therefore, we evaluated LDH release and ROS accumulation to investigate the impact of MSNs on cell membrane stability in E. coli.