A Decision-Making Framework For The Grouping And Testing Of Nanomaterials (Df4nano Grouping)

•DF4nanoGrouping is a functionality-driven concept to group and test nanomaterials.•It addresses all aspects of a nanomaterial’s life cycle and biological pathway.•It is functionality-driven by considering nanomaterial system-dependent properties.•In 3 Tiers, nanomaterials are assigned to 4 main groups with further sub-grouping.•Nanomaterials are grouped by specific modes-of-action resulting in toxic effects.