Prolonged heating of Fe3O4-Au hybrid nanoparticles in a radiofrequency solenoid coil

Abstract

We report the hyperthermia properties of Fe3O4–Au hybrid nanoparticles (HNPs) under a biocompatible alternating magnetic field (AMF) of 1.5 kA m−1 and 200 kHz. The HNPs were prepared by growing Au nanoparticles (AuNPs) with an average diameter of 3 nm on the surface of Fe3O4 magnetic nanoparticles (MNPs) with an average diameter of 10 nm. The structural properties were determined by transmission electron microscopy (TEM), dynamic light scattering (DLS), and X-ray diffraction (XRD). Under the AMF, the initial heating rate of the HNPs solution was lower than that of the MNPs solution because HNPs have a reduced saturation magnetization (Ms) value compared to MNPs. The continued AMF application increased the temperature of the HNPs solution steadily while the MNPs solution reached a thermal equilibrium. The heating effect of AuNPs conjugated to diamagnetic and non-conductive SiO2 nanoparticles (SiO2-AuNPs) was demonstrated under the same AMF condition, which suggests that the prolonged heating of HNPs can be attributed to the additional heating of AuNPs in the radiofrequency (RF) solenoid coil. © 2017 Elsevier B.V.