Optimizing Synthesis Parameters to Achieve Phase-pure Superparamagnetic Fe3O4 Nanoparticles for Magnetic Hyperthermia

Iron oxide nanoparticles (IONPs), particularly magnetite (Fe3O4), are promising agents for magnetic fluid hyperthermia. This study reports a comprehensive optimization of the chemical co-precipitation method focusing on pH, aging time, and washing solvents to synthesize phase-pure, well-dispersed magnetite nanoparticles exhibiting superparamagnetic behaviour. Synchrotron X-ray diffraction along with Rietveld refinement confirmed the formation of a single-phase inverse cubic spinel structure. Field emission scanning electron microscopy revealed the synthesis of spherical nanoparticles with a size range of 15–25 nm. X-ray photoelectron spectroscopy validated the characteristic Fe2+/Fe3+ mixed valance state of magnetite. Magnetic measurements demonstrated saturation magnetization (57.26 emu/g at 298 K and 64.8 emu/g at 5 K) and magnetization-temperature analysis indicated a blocking temperature of 115 K, confirming superparamagnetism. Hyperthermia studies on the optimized sample exhibited a significant temperature increase (up to 13 °C under an 80 Oe AC field at 490 kHz) at a low concentration of 2 mg/ml, demonstrating strong magneto-thermal efficiency. These results highlight the successful synthesis of high-purity magnetite SPIONs with superior heating performance, underscoring their potential for effective magnetic hyperthermia in cancer therapy.