Assessing biological oxidative damage induced by graphene-based materials: An asset for grouping approaches using the FRAS assay.

Graphene-based materials (GBMs) are extremely promising and their increasing number urges scientists to conduct more and more toxicity studies. However, case-by-case approaches are rarely the best options in the earliest phases of industrial processes. Grouping can show great assets in this context: it is defined as the process of gathering substances into a common group. Oxidative stress being a major mechanism of nanotoxicity, an important grouping criterion is the surface reactivity, for which a relevant assessment is the FRAS (ferric reducing ability of the serum) assay. However, the application of the FRAS to GBMs is questioned due to their hydrophobicity. In this study, we explored the relevance and feasibility of the FRAS for grouping, working on 22 GBMs and 2 carbon blacks. We concluded that with few adjustments, the FRAS method appeared perfectly adapted to these materials and allowed a classification as "reactive" or "non-reactive" in agreement with results of ROS production for 84% of our GBMs. While not self-sufficient for toxicity assessment, the FRAS presents interesting qualities: it is fast, cheap, and simple. Therefore, we recommend studying GBMs using the FRAS as a step of a grouping process, a complement to other assays or as an early screening tool.