The growing biomedical field of applications of graphene-based materials raises questions abouttheir short- and long-term (cyto)toxicity [44,45]. It is known that the cytotoxicity of G flakes dependson the flake size. Smaller flakes are more cytotoxic and show higher cellular internalization andaffect cellular functionality to a greater extent [46]. The number of oxygen functional groups that areattached to the surface also plays an important role [47]. For larger C/O levels, flakes are less cytotoxic,which can be correlated to partially reduced GO structures (rGO) [48]. Wu et al. have shown that cellbehavior is strongly responsive to the rGO structure [49]. In particular, they formed few-layer rGOfilms and controlled the reduction level and surface oxygen content. Their results showed the stronginfluence of oxidation levels on cellular behavior, with cell attachment, proliferation, and phenotypebeing best when cells were cultured in proximity to ‘moderately’ reduced GO (mrGO). It was furtherobserved that cell performance decreased significantly with an increased level of thermal reduction.