Yelenich O. Synthesis and properties of nanosized AFe2O4 (A = Mn, Fe, Co, Ni, Zn) ferrispinels from nonaqueous solutions

The synthesis condotion of weakly agglomerated, crystalline nanoparticles AFe2O4 (A = Mn, Fe, Co, Ni, Zn) ferrispinels and core/shell structures based on them by the precipitation from nonaqueous solutions using metal nitrates as starting reagents were determined. It has been found that weakly agglomerated, superparamagnetic nanoparticles with sizes of 2-8 nm are formed during the synthesis by precipitation from diethylene glycol solution method. However, these nanoparticles are slightly heated by the action of an external alternating magnetic field (characterized by low values of specific loss power (SLP)) and therefore do not meet the requirements for hyperthermia. It has been found that an increase in the specific loss power can be achieved by nanoparticles synthesis methods such as cryochemical synthesis or precipitation from microemulsions based on cyclohexane and surfactant Triton X-100, Brij-35, CTAB, or synthesis of (Fe3O4/CoFe2O4) core/shell structures with magnetically soft core and magnetically hard shell, which exhibit high magnetic anisotropy. Based on pre-clinical testing of magnetic fluids developed in this study, the possibility of using the synthesized ferromagnetic nanoparticles as effective inducer of tumor (inoculated Guerin carcinoma) hyperthermia was shown.