Comparative investigation of iron oxide nanoparticles and microparticles using the in vitro bacterial reverse mutation and in vivo Allium chromosome aberration and comet assays

Iron oxide-Fe 2 O 3 nanoparticles-NPs and microparticles-MPs widely used in medical applications were comparatively investigated for in vitro mutagenicity and in vivo cytotoxicity/genotoxicity using the Ames test in Salmonella typhimurium strains (125, 250, 500, 750, 1,000 µg/mL) and chromosome aberration/comet assays in Allium cepa (all concentrations but 1,000 µg/mL), for the first time. Neither of the particles was mutagenic in all the bacterial strains in the media without (-S9) mix. However, with the S9 mix, a significant increase was determined in the reverting colonies in some concentrations in TA 97a. In TA 102, all the concentrations but 125 µg/mL also revealed a significant increase. These effects were regarded as weak mutagens since they were