Characterization of local structure and heat dissipation of iron oxide nanoparticles for magnetic hyperthermia treatment

Abstract

Magnetic hyperthermia treatment (MHT) is a new cancer therapy approach that uses the heat generated by magnetic nanoparticles (MNPs) upon the application of an AC magnetic field. To successfully implement the therapy, it is important to estimate the heat dissipation mechanism based on the magnetic properties. Superparamagnetic iron oxide nanoparticles (SPION) for MHT were prepared using the co-precipitation method. The crystal structures were examined by X-ray diffraction. The average particle size of the samples ranged between 10.4 nm and 11.0 nm, depending on the preparation conditions, such as the pH. The heating and magnetic properties were dependent on not only the particle size but also the preparation conditions. To clarify the electronic state of the iron ions and the local structure, X-ray absorption fine structure (XAFS) measurements were performed. We concluded that the valence of the iron ions and local structures, including lattice vacancies, might be important in estimating the heat dissipation.