Iron Oxide Nanoparticles with Grafted Polymeric Analogue of Dimethyl Sulfoxide as Potential Magnetic Resonance Imaging Contrast Agents

Novel water-dispersible hybrid iron oxide nanoparticles grafted with a polymeric analogue of dimethyl sulfoxide (DMSO) were prepared. Superparamagnetic iron oxide nanoparticles with immobilized atom-transfer radical polymerization (ATRP) initiators were prepared via an in situ method using 12-(2-bromoisobutyramido)dodecanoic acid as a surface ligand/initiator. The initiator-functionalized particles were employed in a surface-initiated initiator for continuous activator regeneration ATRP to graft poly(2-(methylsulfinyl)ethyl acrylate) (a polyacrylate analogue of DMSO) from the surface. The resulting hybrid nanoparticles showed a high magnetic relaxivity ratio ( r₂/ r₁) of 600 at 7 T in fetal bovine serum, and a good biocompatibility up to 1000 mg L^-1.