Cytotoxicity of Fourth Period Transition Metal Oxide Nanoparticles Depends on Certain Physicochemical Properties

Y.-W. Huang, C.C. Chusuei, C.-H. Wu, S. Mallavarapu, J.G. Winiarz, R.S. Aronstam
Missouri University of Science and Technology, US

Keywords: physicochemical properties, metal oxide nanoparticles, cytotoxicity, available surface binding site, point–of-zero charge, metal ion dissolution

Summary:

Though we have assessed nanoparticle-induced cytotoxicity and identified inter-relationships among elevated oxidative stress, perturbation of calcium homeostasis, and types of cell death, the physicochemical properties of nanoparticles that lead to cytotoxicity remain to be elucidated. Our aim in this study is to systematically identify physicochemical properties of fourth period transition metal oxide nanoparticles TiO2, Cr2O3, Mn2O3, Fe2O3, NiO, CuO, and ZnO that govern cytotoxicity. We found that cytotoxicity increased with the atomic number of the transition metal oxides. The trend of toxicity was not cell type specific as we observed in two lung cancerous and non-cancerous cell lines. Our results indicate that cytotoxicity is a function of particle surface charge, the relative number of available surface binding sites, and metal ion dissolution from NPs. The significance of this work is that our findings inform both risk assessment and the design of safer nanomaterials. The latter is critically important in making biocompatible nanomaterials for biomedical applications.