(612a) Comparison of the Mechanism of Toxicity of Binary Metal Oxide Nanoparticles Based On Dissolution and Oxidative Stress Properties

Nanomaterials (NM) are potential candidates with promising physicochemical properties and strong affinity towards biological substrates and processes. For this reason, several binary (TiO2, ZnO, and CeO2) were synthesized by Flame Spray Pyrolysis (FSP) technique to investigate the biological activities such as cellular uptake, subcellular localization, and toxic effects exhibited by these NMs based on oxidative stress and cytotoxicity. ZnO induced toxicity at the level of ≥ 50μg/ml concentration leading to the generation of reactive oxygen species (ROS), oxidant injury, excitation of inflammation and eventually cell death. Using ICP-MS and fluorescent-labelled ZnO, we found that NM dissolution could take part in culture medium and also in the endosomes. Fluorescent-labelled CeO2 nanoparticles were taken up into positive endosomal compartments free from toxicity and inflammation suppressing ROS production inducing cellular resistance to an exogenous source of oxidative stress. Fluorescent-labelled TiO2 was processed by the same uptake pathways as CeO2 but did not response towards any adverse or protective effects. These results demonstrate that metal oxide nanoparticles induce a range of biological responses that vary from cytotoxic to cytoprotective and can be properly understood by using a tiered test strategy developed for oxidative stress which could also successfully be extended towards cellular toxicity determination.