Potential toxicity effects of magnetic nanoparticles (MNPs) collected from in vitro and in vivo experiments. The common strategies for risk assessment for MNPs, including cell culture, zebrafish, chicken and rodents are summarized in the central yellow panel. The potential toxicity effects of MNPs have been categorized by mechanism, such as inhibition of cellular proliferation, temporary/absolute cell cycle cessation, DNA genotoxicity, damage of cellular components and aggregation to blocking of cell membranes on a cellular level. Some studies have reported MNPs’ toxicity effects on a whole organism level and elaborated the interactions of MNPs inside the body (see the summary in Table 1 for detail literature citations).