Analysis of TiO2 nanoparticles accumulation in vitro

The physicochemical properties of titanium dioxide (TiO2) in nanoforms is often exploited as colorant in food, pharmaceuticals and other consumer products. However, the current evidence of potential hazards associated with titanium dioxide (TiO2) in nanoforms led to a ban of TiO2 as food additive in Europe. This regulatory decision has also an impact on thousands of pharmaceuticals. In the present study, we tested the internalisation, accumulation and resulting biological effects of different types of TiO2 nanomaterial in short and long-term vitro cultures. Even if we could demonstrate that all tested cell lines were able to take up and accumulate nanomaterial for a period of up to 30 days, the cellular responses using conventional in vitro tests were limited in all tested cell lines. Nevertheless, a transcriptomics study revealed that that the response to the accumulated material differed between two selected cell types. A keratinocyte like cell line reacted with a modified rate of keratinogenesis whereas the enterocyte like cell demonstrated mainly interactions with cell homeostasis. To further clarify possible harmful effects of TiO2, the study suggests analyzing cell/tissue type specific effects of TiO2.