Cobalt doped Fe3O4 nanoparticles with improved magnetic anisotropy and enhanced hyperthermic efficiency

Abstract

Magnetite nanoparticles are promising candidates for Magnetic Fluid Hyperthermia in cancer treatment, exploiting alternating magnetic fields to selectively generate heat in tumor tissues. However, achieving optimal hyperthermic efficiency within the clinical therapeutic window remains challenging due to the need for precise tuning of their magnetic and physical properties. To address this, we investigated the effects of doping Fe₃O₄ nanoparticles with varying concentrations of cobalt to enhance their magnetic properties, such as anisotropy constant and saturation magnetization. We synthesized a series of cobalt-doped Fe₃O₄ nanoparticles and characterized their physical and magnetic properties using X-ray diffraction, Fourier Transform Infrared spectroscopy, High-Resolution Transmission Electron Microscopy, and Vibrating Sample Magnetometry. Our results show that cobalt doping increases the coercivity of SPIONs, with values rising from 21.98 Oe at 2 wt% doping to 57.54 Oe at 5 wt% doping. However, this increase remains within a range that does not alter the superparamagnetic nature of the nanoparticles. The 2 % cobalt-doped Fe₃O₄ achieved a SAR of 25.87 W/g and an ESAR of 0.81 nH m²/kg, marking a substantial improvement over undoped Fe₃O_4. However, higher cobalt concentrations reduced hyperthermic efficiency. These findings suggest that low-level cobalt doping is an effective strategy to enhance the hyperthermic performance of Fe₃O₄ nanoparticles by improving the anisotropy and addressing the current limitations in magnetic hyperthermia applications.