Synthesis of Fe 3 O 4 @Au core–shell nanoparticles

A new two-step synthesis of Fe3O4@Au core–shell nanoparticles stabilized in polyethylene glycol is described. The nanoparticles were characterized by transmission electron microscopy, X-ray powder diffraction, UV and Mossbauer spectroscopy. Fe3O4@Au nanoparticles featured both optical properties (they featured a plasmon resonance band) and magnetic properties (they responded to an external magnetic field), typical of individual gold and magnetite nanoparticles, respectively.