In vitro toxicity of two functionalized reduced graphene oxide materials with potential application in food packaging

Functionalized graphene materials have been proposed as nanofillers in food packaging applications as they improve the characteristics of the resulting nanocomposites. But food contact materials require a toxicity evaluation previous their authorization and use. In this sense, reduced graphene oxide functionalized with dodecyl amine (DA-rGO), and [2-(methacryloyloxy) ethyl] trimethylammonium chloride (MTAC-rGO) were characterized and their internalization and cytotoxicity in Caco-2 and HepG2 cultures evaluated. Cell viability decreased from 100 μg/mL in all experimental trials, and oxidative stress by means of a reduction in glutathione levels was evidenced as one of the potential toxicity mechanisms involved. Moreover, both materials were subjected to an in vitro digestion process to investigate their potential changes along the gastrointestinal tract. Digested samples were characterized, and the cytotoxicity also evaluated showing an exacerbation. These results raise concerns about the impact of these materials after oral exposure, and therefore further research is necessary.