Abstract
Manganese oxide nanoparticles (MnO(x) NPs) are finding applications in several environmentally important areas such as farming and energy storage. MnO(x) NPs span a range of metal oxidation states that open up a wide range of applications in catalysis as well. As a result, it is important to understand how such materials can impact human health through incidental exposure. In this study, we examined a range of commercially available Mn(2)O(3) NPs and compared our characterization data to those supplied by manufacturers. Discrepancies were noted and then measured values were used to assess the biological impact of these materials on three mammalian cell lines-A549, HepG2 and J774A.1 cells. Cell toxicity assays showed that all Mn(2)O(3) particles exhibited cytotoxic effects that may be correlated, at least in part, to the production of reactive oxygen species. All eight nanoforms also activated caspase 3 but not caspase 1, although the magnitude of these changes varied greatly between materials.