Influence of the heat treatment conditions on the properties of gallium-strontium-substituted manganese ferrites designed for magnetic hyperthermia applications

Magnetic nanoparticles (MNPs) with cores made of mixed ferrites may find application in the field of magnetic hyperthermia, this due to their intrinsic characteristics such as nanometric sizes, biocompatibility and the capability of transforming mechanical energy into heat under the action of an external magnetic field. In this study, the synthesis of Mn, Ga and Sr-containing ferrites (Mn0.5Ga0.5-xSrxFe2O4, x = 0.05 and 0.1) via sol-gel was carried out evaluating the effect of the heat treatment conditions on the physicochemical properties. The obtained materials were characterized by X-ray diffraction (XRD), vibrating sample magnetometry (VSM), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). Additionally, the heating ability of the obtained nanoparticles was evaluated by magnetic induction and an in vitro hemolysis assay was also performed. Within the tested heat treatment conditions (150-600 degrees C and 30-120 min) it was possible to obtain nanosized magnetic ferrites with a single crystalline phase, corresponding to the cubic inverse spinel structure, and with a behavior close to the superparamagnetic regime. Moreover, selected materials showed heating ability under the application of a magnetic field and were non-hemolytic in contact with human blood red cells, making them suitable for their use as heating agents for the magnetic hyperthermia treatment.