Abstract. Core/shell structured iron(Fe)/gold(Au) nanoparticles have been prepared by a reverse micelle method, and their potential application as magnetic resonance (MR) contrast agent investigated. The average nanoparticle size is 19 nm, as determined by x-ray powder diffraction (XRD) and transmission electron microscopy (TEM). Magnetic properties and relaxivities of nanoparticles are presented and compared. The saturation magnetization is 81 emu g⁻¹ Fe for freshly prepared nanoparticles and the particles have high r₁(6.87 mM⁻¹ s⁻¹) when the Fe core is kept from oxidation. These nanoparticles may be used as T₁ agents in the unoxidized form.

Print publication: Issue 3 (14 February 2006)
Received 9 August 2005, in final form 21 November 2005
Published 6 January 2006