Cutaneous Applied Nano-ZnO Reduces the Ability of Hair Follicle Stem Cells to Differentiate

The study investigated the effects of nano-Zinc oxide (nZnO) on hair follicle physiology, particularly focusing on hair follicle stem cells (HFSCs). It was found that nZnO, when applied topically to newborn mice, accumulated in hair follicles and induced apoptosis of HFSCs. In vitro studies supported these findings, showing DNA damage and apoptosis in HFSCs due to nZnO exposure. Additionally, nZnO exposure disrupted genes related to HFSC apoptosis, cell communication, and differentiation, ultimately reducing the differentiation potential of HFSCs. This research highlighted a potential risk of using ZnO nanoparticles in topical applications, such as sunscreens, on skin homeostasis.