Facile synthesis of Fe@Fe2O3 nanochains exhibiting high heating efficiency in magnetic hyperthermia

• Fe@Fe2O3 nanochains are prepared by reduction of Fe2+ ions by NaBH4 in aqueous solution.
• The nanochains show typical ferromagnetic properties with high Ms and notable coercivity.
• The nanochains exhibit higher heating efficiency than that of SPM iron oxide nanoparticles.

Ferromagnetic nanoparticles (NPs), with high heating efficiency, have great potential as heating elements for use in magnetic hyperthermia and thermoablation therapies. In this work, core@shell structured Fe@Fe2O3 nanochains were prepared by facile chemical reduction of Fe2+ ions in aqueous solution. The resulting nanochains were characterized by X-ray powder diffraction(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM), elemental mapping, Raman analysis, and magnetization measurements. It was found that Fe nanochains form through connection of Fe nanospheres one by one and are coated by amorphous Fe2O3 layer. The chains are about 50–100 nm in diameter and several micrometers in length. Magnetic measurements revealed that as-prepared nanoconstructs possess typical ferromagnetism with a characteristic blocking temperature above 400 K. The saturation magnetization of the samples prepared at 25 °C, 40 °C and 80 °C are 118.6, 81.9, 22.8 emu/g and the coercivity are 136, 259 and 411Oe, respectively. It was interesting to find that these nanochains, dispersed in water at physiological pH, present higher heating efficiency than that of superparamagnetic ferrite NPs. The enhanced heating performance of Fe@Fe2O3 nanochains may be attributed to the activation of a magnetic hysteresis loss mechanism. This study indicates that the resulting Fe@Fe2O3 nanochains are promising materials in magnetic hyperthermia and thermoablation therapies.

Core@shell structured Fe@Fe2O3 nanochains with ferromagnetic behavior and distinct shape anisotropy were prepared by facile chemical reduction of Fe2+ ions in aqueous solution. The Fe@Fe2O3 nanochains demonstrate high heating efficiency and have potential to be used in magnetic hyperthermia and thermoablation therapies.Figure optionsDownload as PowerPoint slide