Grouping of nanomaterials for risk assessment

2013; Schluesener and Schluesener 2013), study the biokinetics (Landsiedel et al. 2012; Klein et al. 2012) or establish in vitro systems for testing of nanomaterials (Hoelting et al. 2013; Haase et al. 2012; Kroll et al. 2012). However, because of the high number of different materials and the difficulty to interpret many of the in vitro studies with respect to their in vivo relevance, the present categorization concept proposed by Gebel et al. (2014) will contribute to a better overview and a more straightforward hazard identification. When novel nanomaterials have to be evaluated, it seems reasonable to check initially whether they fulfill one of the three “Gebel-criteria.” Besides introducing the novel categorization concept, the review addresses the question whether nanomaterials act by novel mechanisms. The authors conclude that despite the intensive research in this field, not a single “nanospecific” mechanism of action has been identified so far. All molecular mechanisms described for nanomaterials have already been identified for chemicals or described in conventional particle toxicology. The present article (Gebel et al. 2014) is of high interest to anyone working in the field of nanotoxicity, because it introduces a straightforward concept and gives the risk evaluator a better overview.