Toxicity induced by iron oxide nanoparticles. A: In vitro survival of HUVEC and SMC exposed to increasing amounts of uncoated USPIO, FMN-coated USPIO (FLUSPIO), and dextran- and sodium citrate-coated USPIO (Sinerem). B-C: Short- and long-term impact of iron oxide nanoparticle exposure on zebrafish embryo development, showing a partially very good, and a partially discordant correlation with in vitro findings. In vitro, neither of the three formulations demonstrated toxicity at doses up until 10 mM. In vivo, on the other hand, uncoated USPIO were found to be toxic at a dose of 10 mM.