RESUMO
Graphene and related materials (GRMs) have unique optical and thermal characteristics and are expected to be adopted for industrial applications. However, there are concerns with respect to their safety to human health. To conduct cytotoxicity and mutagenicity assessments, exfoliated graphene (EGr) dispersed in Tween-20® was diluted in cell culture medium. Rat alveolar macrophage viability significantly decreased after 24â¯h exposure to 1 and 10⯵g/mL EGr. No significant levels of intracellular reactive oxygen species were detected in the 2',7'-dichlorodihydrofluorescin diacetate assay after 24â¯h of exposure to EGr. The levels of the pro-inflammatory cytokines macrophage inflammatory protein-1α, interleukin (IL)-1ß, IL-18, macrophage chemoattractant protein-1, and tumor necrosis factor α were significantly higher in cells treated with 10⯵g/mL EGr for 24â¯h than in untreated controls. Transmission electron microscopy confirmed that EGr was present in the cytoplasm of the cells. Many genes were upregulated by EGr treatment, and significantly overrepresented gene ontology categories included the biological processes "response to external stimulus", "response to stress", "cell-cell signaling", "biological adhesion", and "cell proliferation". EGr did not induce genetic mutations in E. coli or cause micronucleus induction in mouse bone marrow cells. The results suggest that EGr cytotoxicity should be carefully considered.