Effects of Nanomaterials on Human Buccal Epithelium

Abstract

Due to the widespread usage of nanomaterials (NM) in commercial products, it is pivotal to examine the impact NM exert on human health. The impact of NM found in commercially available toothpastes, namely, titanium dioxide (TiO2), silicon dioxide (SiO2) and hydroxyapatite (HA) were assessed using an in vitro human buccal epithelial cell model. All pristine NM tested were internalized into the cells and clathrin-mediated endocytosis was identified as the main route of entry. The NM uptake led to elevated ROS level and increased expressions of inflammatory cytokines. However, pristine NM did not affect protein expressions involved in cell cycle progression and apoptotic events suggesting the existence of an adaptive mechanism to counteract NM induced oxidative stress. The cells? wound healing capacity was impaired by HA, SiO2 and TiO2 NM. This finding was confirmed by the significant recovery of wound healing when internalization of NM were prevented by blocking clathrin-mediated endocytosis.