Graphene-related materials (GRMs) are widely used in various applications due to their unique properties. A growing number of reports describe the impact of different carbon nanomaterials, including graphene oxide (GO), reduced GO (rGO), and carbon nanotubes (CNT), on immune cells, but there is still a very limited number of studies on graphene. In this work, we investigated the biological responses of few layer graphene (FLG) on mouse macrophages (bone marrow derived macrophages, BMDMs), which are part of the first line of defense in innate immunity. In particular, our paper describes our findings of short-term FLG treatment in BMDMs with a focus on observing material internalization and changes in general cell morphology. Subsequent investigation of cytotoxicity parameters showed that increasing doses of FLG did not hamper the viability of cells and did not trigger inflammatory responses. Basal level induced autophagic activity sufficed to maintain the cellular homeostasis of FLG treated cells. Our results shed light on the impact of FLG on primary macrophages and show that FLG does not elicit immunological responses leading to cell death.

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.