Comparison of cytotoxicity of α-Al2O3 and η-Al2O3 nanoparticles toward neuronal and bronchial cells

The role of the crystalline structure on the toxicity of two phases of Al2O3 NPs, alpha (alpha-Al2O3 NPs) and eta (eta-Al2O3 NPs), was investigated in this study. Different techniques were employed for the characterization of the Al2O3 NPs and multiple toxicological endpoints were used to assess the toxicity toward mouse neuroblastoma (N2A) and human bronchial epithelial (SEAS-2B) cells. Based on the results of the multiple toxicological endpoints, revealed differences in the toxic potential results for alpha-Al2O3 NPs and eta-Al2O3 NPs, with the latter showing a more pronounced effect. These effects could be due to the high uptake of the eta-Al2O3 NPs in the cytoplasmic vesicles, as evidenced by TEM and ICP-MS. Hence, the results demonstrate the potential toxicity of both alpha-Al2O3 NPs and eta-Al2O3 NPs, although the N2A and BEAS-2B cells showed greater susceptibility toward eta-Al2O3 NPs. Thus, our study demonstrates the important role of the crystalline structure in relation to the nanotoxicity of Al2O3 NPs.