Nevertheless, elemental iron has a much larger magnetic susceptibility than iron oxides; therefore, it has immense potential if it is able to be stabilized in a nanoscale form. As a result, Carpenter et al designed iron nanoparticles passivated by a gold coating in order to stabilize the iron core and delay its oxidation.11,12 These iron core–gold shell nanoparticles (Fe@Au) have been proposed for use as MRI contrast agents,13 CT contrast agents,14 molecular diagnostic tools,15 magnetic guidable drug-carriers,14 and thermotherapeutic probes.