Such a study have been performed to provide samples of interest for correlative imaging using the npSCOPE instrument. Partner TOXALIM showed no major impact of 22 nm TiO2 (P25, Degussa) on barrier integrity and no evidence of DNA strand breaks in human buccal epithelial TR146 cells cultured in vitro on filters and exposed for 24 hours to exposure concentrations up to 100 µg/ml. However, a dose-dependent chromatin remodeling was observed, which could be decreased again when the nanoparticles were washed out after 2 hours exposure. Whether the TiO2 nanoparticles are directly and physically involved in altering the chromatin structure in the nucleus will be further investigated through combined TEM and HIM-SIM analyses of the exposed cells.
Partner LIST has performed benchmarking HIM-SIM analyses on its 3D co-culture model of the small intestine (Caco-2/TC7 gut epithelial cells combined with HT29 mucus-secreting goblet cells) exposed to TiO2 nanoparticle after in vitro simulated digestion (cf. Figure).