Synthesis and characterization of PVP-coated large core iron oxide nanoparticles as an MRI contrast agent

The purpose of this study was to synthesize biocompatible polyvinylpyrrolidone ( PVP)-coated iron oxide ( PVP-IO) nanoparticles and to evaluate their efficacy as a magnetic resonance imaging ( MRI) contrast agent. The PVP-IO nanoparticles were synthesized by a thermal decomposition method and characterized by x-ray diffraction ( XRD), transmission electron microscopy ( TEM), dynamic light scattering ( DLS), and a superconducting quantum interface device ( SQUID). The core size of the particles is about 8-10 nm and the overall size is around 20-30 nm. The measured r(2) ( reciprocal of T-2 relaxation time) and r(2)* ( reciprocal of T-2* relaxation time) are 141.2 and 338.1 ( s mM)(-1), respectively. The particles are highly soluble and stable in various buffers and in serum. The macrophage uptake of PVP-IO is comparable to that of Feridex as measured by a Prussian blue iron stain and phantom study. The signal intensity of a rabbit liver was effectively reduced after intravenous administration of PVP-IO. Therefore PVP-IO nanoparticles are potentially useful for T-2-weighted MR imaging.