Titanium dioxide nanoparticles induced intracellular calcium homeostasis modification in primary human keratinocytes. Towards an in vitro explanation of titanium dioxide nanoparticles toxicity

Deciphering the molecular basis of toxicological mechanism induced by nanoparticles (NPs) remains an essential challenge. Ion Beam Analysis (IBA) was applied in combination with Transmission Electron Microscopy and Confocal Microscopy to analyse human keratinocytes exposed to TiO2-NPs. Investigating chemical elemental distributions using IBA gives rise to a fine quantification of the TiO2-NPs uptake within a cell and to the determination of the intracellular chemical modifications after TiO2-NPs internalisation. In addition, fluorescent dye-modified TiO2-NPs have been synthesised to allow their detection, precise quantification and tracking in vitro. The internalisation of these TiO2-NPs altered the calcium homeostasis and induced a decrease in cell proliferation associated with an early keratinocyte differentiation, without any indication of cell death. In addition, the relation between the surface chemistry of the TiO2-NPs and their in vitro toxicity is clearly established and emphasises the importance of the calcium homeostasis alteration in response to the presence of TiO2-NPs.

Authors: Simon, Marina; Barberet, Philippe; Delville, Marie-Helene; Moretto, Philippe; Senec, Herve ;Full Source: Nanotoxicology 2011, 5(2), 125-139 (Eng) ;