Figure 5. Hazardous nanomaterial properties leading to ROS generation and induction of integrated events in cytotoxicity pathway.

Nanomaterials induce ROS production as a direct consequence of specific material properties or as a consequence of triggering cellular injury responses leading to oxidant radical generation. ROS production could trigger a range of oxidative stress effects as outlined in the hierarchical oxidative stress model. The induction of cellular toxicity at the highest level of oxidative stress involves a number of interrelated cellular responses that include intracellular Ca²⁺ release and mitochondrial perturbation leading to cell death with accompanying changes in cell membrane integrity and nuclear PI uptake.