Magnetic iron nanoparticles for in vivo targeted delivery and as biocompatible contrast agents

Iron nanoparticles (NPs) of size less than 20 nm were synthesized using an in-house developed cryomill. These NPs exhibit values of saturation magnetisation (similar to 180 emu g(-1)) close to that of pure iron. The particles were found to be nontoxic at concentrations required for MRI imaging as indicated by MTT assay. In vivo studies demonstrated the suitability of using these particles as contrast agents for MRI. The iron NPs were bio-capped with TRITC-dextran and injected into mice to study the transport behavior of the NPs under the influence of an external magnetic field. The iron NPs showed enhanced aggregation and contrast when a bar magnet was placed on the mice as observed by whole body fluorescence imaging