Effect assessment of engineered nanoparticles in solid media - Current insight and the way forward.

Engineered Nanoparticles (ENPs) present novel/added challenges to the established effect assessment modus operandi, requiring an update of used methods. ENPs are dimensionally and physically different from conventional chemicals, which imply that the metrics with which we relate effect and the type of effect responses are different from that of the conventional approach. Effects on organisms are often preceded by changes on the sub-organismal level (cell, genes), dedicated tools have vast potential to detect earlier (and link to) effects on higher levels of organization. High-throughput screening (HTS) is rapid, cost-effective and specific. One way forward is to link HTS to population outcomes, targeting a systems toxicology approach. Although the benefits of integrating various levels of information may seem obvious, this is an even more decisive aspect when rapid answers are needed for ENPs. Here we rank the available tools/methods, highlight main study gaps and list priority needs and the way forward.