Superparamagnetic Fe₃O₄ magnetic nanoparticles and their potential for hyperthermia treatment for cancer

The heating efficiency of Fe₃O₄ nanoparticles of different sizes synthesized using supercritical conditions of liquids, under different applied magnetic field intensities and frequencies, was investigated through experimental measurements of specific absorption rate (SAR). The synthesis conditions have been varied in order to obtain different sizes and shapes of Fe₃O₄ nanoparticles and to examine their effect on the SAR values. The morphology and crystal structure characterization of three samples revealed cubic-like shapes with average sizes of 63, 128, and 91 nm and formation of FCC Fe₃O₄ phase structure. The magnetic properties were characterized using magnetization dependent of magnetic field and temperature up to 3 T and 400 K respectively. The samples exhibit superparamagnetic-like behavior at room temperature with saturation magnetization Ms of 108, 74, and 77 emu/g and blocking temperatures T_B of 320, 235, and 192 K, respectively. SAR values at 400 Oe and 304 kHz were measured using D5 hyperthermia system to be 126, 33 and 73 W/g for sizes of 63, 91, and 128 nm, respectively. The results yield efficient heating and the nanoparticles perfect feasibility for magnetic hyperthermia treatment of cancer.