Fe ∕ Fe oxide nanocomposite particles with large specific absorption rate for hyperthermia

Using a water-in-oil microemulsion with cetyl trimethyl ammonium bromide as the surfactant, iron was reduced to form a metallic core on which a passivating oxide shell was grown. Transmission electron microscopy, vibrating sample magnetometry, and heating measurements were used to characterize these monodispersed magnetic $\mathrm{Fe}∕{\mathrm{Fe}}_3{\mathrm{O}}_4$ composite nanoparticles with respect to the possible application for magnetic hyperthermia treatments of cancer. The aim is to utilize the fact that an iron core (high saturation magnetization) will give a greater heating effect than iron oxide, while the iron oxide coating will allow the nanoparticles to be observed using magnetic resonance imaging so that therapy can be effectively monitored and targeted. The largest specific absorption rate obtained was $345\mathrm{W}∕\mathrm{g}$ under an alternating magnetic field of $150\mathrm{Oe}$ at $250\mathrm{kHz}$ .