Core/shell structured iron/iron-oxide nanoparticles as excellent MRI contrast enhancement agents

We report the use of metallic iron-based nanoparticles for magnetic resonance imaging (MRI) applications. Core/shell structured iron-based nanoparticles prepared by thermally decomposing organo-metallic compounds of iron at high temperature in the presence of hydrophobic surfactants were coated and stabilized in the aqueous solvent using the newly developed polysiloxane PEO–b–PγMPS (poly(ethylene oxide)–block–poly (γ methacryloxypropyl trimethyl oxysilane)) diblock copolymers. Particles are well suspended in water and retain their core–shell morphology after coating with the copolymer. In comparison to the conventionally used iron-oxide nanoparticles, core/shell structured iron/iron-oxide nanoparticles offer a much stronger T2 shortening effect than that of iron-oxide with the same core size due to their better magnetic properties.

► Core/shell Fe/Fe-oxide nanoparticles were synthesized by organo-metallic synthesis.
► Water dispersibility was obtained by coating particles with a polysiloxane diblock copolymer.
► In comparison to Fe-oxide, Fe/Fe-oxide nanoparticles offer a much stronger T2 shortening effect.