Safety Assessment of nanomaterials using the DF4nanoGrouping decision-making framework

J.H.E. Arts, M.-A. Irfan, A.M. Keene, R. Kreiling, D. Lyon, M. Maier, K. Michel, N. Neubauer, T. Petry, U.G. Sauer, D. Warheit, K. Wiench, W. Wohlleben, R. Landsiedel

Keywords: material properties, system-dependent properties, effects in vitro, Short-term inhalation study, grouping, hazard assessment, risk assessment


The European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC) ‘Nano Task Force’ proposes a Decision-making framework for the grouping and testing of nanomaterials (DF4nanoGrouping) consisting of 3 tiers to assign nanomaterials to 4 main groups (with possible further sub-grouping) and to refine specific information needs. The DF4nanoGrouping covers all relevant aspects of a nanomaterial’s life cycle and biological pathways: intrinsic material and system-dependent properties, biopersistence, uptake and biodistribution, cellular and apical toxic effects. Use, release and exposure route may be applied as ‘qualifiers’ to determine if, e.g., nanomaterials cannot be released from products, which may justify waiving of testing. The four main groups encompass (1) soluble, (2) biopersistent high aspect ratio, (3) passive, and (4) active nanomaterials. The DF4nanoGrouping foresees a stepwise evaluation of nanomaterial properties and effects with increasing biological complexity: As necessary, intrinsic material properties, system-dependent properties (e.g. surface reactivity and dispersibility that are dependent upon the nanomaterial’s respective surroundings, such as culture media or lung lining fluid) and in vitro effects are assessed. In vitro cytotoxicity testing (preferably using alveolar macrophages as relevant in vitro test system for inhalation exposure) plays a central role in determining nanomaterial functionalities. The DF4nanoGrouping facilitates grouping and targeted testing of nanomaterials. It ensures that sufficient data for grouping and ultimately risk assessment of a nanomaterial are available, and it fosters the use of non-animal methods. At the same time, no studies are performed that do not provide crucial data. Thereby, the DF4nanoGrouping serves to save both animals and resources.