Safety screening of MNMs. MNMs of the same chemical composition can vary in many ways (e.g. size, shape, charge). In essence, current regulatory requirements would require testing all different variations or forms. To perform a risk assessment for all different variations of MNMs in a fast and efficient way, innovation within the risk assessment and regulatory process of MNMs is advisable. Moreover, insight in potential hazard or risks is needed during the early stages of innovation without performing an extensive testing strategy. Here, we propose a first screening strategy to identify potential risks of MNMs at early stages of innovation. When innovations progress towards market application, information has to be lined up in the direction of regulatory requirements. We therefore suggest for the first stages of innovation to identify the potential for health risks, followed by indicators for risk at mid stages of innovation, and to be finalized by demonstrators for health risks as laid down in regulatory requirements (see Figure 3). This approach aims at improved insights into health risks, both environmental as human, before marketing of innovative MNM or nanoproducts. Moreover, it supports decisions at the various stages of development e.g. for further investments, thereby supporting to build a strong business case.
