Synthesis and characterization of radiopaque magnetic core-shell nanopar-ticles for x-ray Imaging applications

Radiopaque magnetic gamma-Fe2O3/poly(2-methacrylovioxvethvl(2,3,5-triiodobenzoate)) core-shell nanoparticies of narrow size distribution were prepared by emulsion pollymerization of the iodinated monomer 2-methacryloyloxyethyi(2,3,5-triiodobenzoate) in the presence of maghemite (gamma-Fe2O3) nanoparticles of about 15 nm average diameter. The effect of the iodinated monomer concentration on the percent of the radiopaque shell coating has been elucidated. Characterization of these radiopaque core-shell particles was accomplished by methods such as FTIR, TGA, TEM, HRTEM, iodine analysis, and magnetic susceptibility measurements. The radiopacity of the dried and water dispersed core-shell nanoparticles was demonstrated by an imaging technique based on X-ray absorption usually used in hospitals. gamma-Fe2O3 nanoparticles coated with a dextran shell are commonly used as contrast agents for magnetic resonance imaging (MRI). The present nanoparticles have similar core-shell structure substituting the dextran for the iodo polymer. These core-shell nanoparticles may therefore be useful as imaging contrast agents to detect various pathogenic zones and to observe different disease states in both modes: X-ray and MR1. (C) 2007 Wiley Periodicals, Inc.