In Vivo Clearance and Toxicity of Monodisperse Iron Oxide Nanocrystals

Thermal decomposition of organometallic precursors has been found to generate highly crystalline iron oxide (10) nanocrystals that display superior MR contrast and lower polydispersity than 10 nanocrystals synthesized by aqueous precipitation. In the present study, the in vivo characteristics of 10 nanocrystals prepared by the thermal decomposition route and then coated with a phospholipid containing a pendant poly(ethylene glycol) chain are examined. The size and surface chemistry of the 10 nanocrystal influence the biodistibution, the rate of biodegradation and bioclearance, and the biodegradation products. We conclude that the in vivo fate of PEGylated monodisperse 10 nanocrystals and the iron, phospholipid, and oleic acid biodegradation products may influence the cellular environments in the organs and blood that can determine their safety in the body.