Iron Oxide Nanoparticle Clusters for Biomedical Applications

Iron Oxide nanoparticles find a broad range of biomedical applications from T2 MRI contract agents, to hyperthermia cancer treatment. Recently, it was reported that hierarchical assemblies of Fe₃O₄ particles have much higher SLP/SAR values than the isolated superparamagnetic Fe₃O₄ nanoparticles.¹
In this study, we chemically synthesized nanoparticle clusters (NPCS) in an oil-in-water emulsion system. The NPCs have spherical shape and are composed of uniform individual superparamagnetic nanoparticles with average size of 10 nm, which have been synthesized separately. Powder XRD studies reveal that the particles have the Fe₃O₄ phase. Dynamic Light Scattering (DLS) shows that the NPCs have a hydrodynamic diameter in the range of 120 to 165 nm. The growth of nanoparticle clusters has been studied by TEM measurements and is in good agreement with the DLS values. In order to increase the stability of the NPCs, they were coated with SiO₂ shells following a modified Stober method. The thickness of silica shell was controlled by changing the TEOS amount. The magnetic and hyperthermia behavior of the NPCS is currently being studied and the results will be presented and discussed.