Partial reversibility of the cytotoxic effect induced by graphene-based materials in skin keratinocytes

In the frame of graphene-based material (GBM) hazard characterization, particular attention should be given to the cutaneous effects. Hence, this study investigates if HaCaT skin keratinocytes exposed to high concentrations of few-layer graphene (FLG) or partially dehydrated graphene oxide (d-GO) for a short time can recover from the cytotoxic insult, measured by means of cell viability, mitochondrial damage and oxidative stress, after GBM removal from the cell medium. When compared to 24 or 72 h continuous exposure, recovery experiments suggest that the cytotoxicity induced by 24 h exposure to GBM is only partially recovered after 48 h culture in GBM-free medium. This partial recovery, higher for FLG as compared to GO, is not mediated by autophagy and could be the consequence of GBM internalization into cells. The ability of GBMs to be internalized inside keratinocytes together with the partial reversibility of the cellular damage is important in assessing the risk associated with skin exposure to GBM-containing devices.