Toxicity of engineered nanomaterials with different physicochemical properties and the role of protein corona on cellular uptake and intrinsic ROS production.

The Organisation for Economic Co-operation and Development has listed thirteen engineered nanomaterials (ENM) in order to investigate their toxicity on human health. Silicon dioxide (SiO) and titanium dioxide (TiO) are included on that list and we added indium tin oxide (ITO) nanoparticles (NPs) to our study, which is not listed on OECD suggested ENM to be investigated, however ITO NPs has a high potential of industrial production. We evaluate the physicochemical properties of SiO NPs (10-20 nm), TiO nanofibers (NFs; 3 μm length) and ITO NPs (<50 nm) and the impact of protein-corona formation on cell internalization. Then, we evaluated the toxicity of uncoated ENM on human lung epithelial cells exposed to 10 and 50 μg/cm for 24 h. TiO NFs showed the highest capability to adsorb proteins onto the particle surface followed by SiO NPs and ITO NPs after acellular incubation with fetal bovine serum. The protein adsorption had no impact on Alizarin Red S conjugation, intrinsic properties for reactive oxygen (ROS) formation or cell uptake for all types of ENM. Moreover, TiO NFs induced highest cell alterations in human lung epithelial cells exposed to 10 and 50 μg/cm while ITO NPs induced moderated cytotoxicity and SiO NPs caused even lower cytotoxicity under the same conditions. DNA, proteins and lipids were mainly affected by TiO NFs followed by SiO NPs with toxic effects in protein and lipids while limited variations were detected after exposure to ITO NPs on spectra analyzed by Fourier Transform Infrared Spectroscopy.