Magnetic Properties, Self-Temperature Rising Characteristics, and Biocompatibility of NiFe O Nanoparticles for Hyperthermia Applications

This paper reports first on the very promising self-heating and temperature rising characteristics of solid-state NiFe₂O₄ nanoparticles for hyperthermia applications. NiFe₂O₄ nanoparticles were prepared by using both the "high temperature thermal decomposition method (HTTD)" and the "newly modified sol-gel" methods. The magnetic properties and cell-cytotoxic properties of the synthesized NiFe₂O₄ nanoparticles were investigated to consider these nanoparticles for in vivo hyperthermia applications. The saturation magnetic moments measured by a high sensitive SQUID were between 43.0 and 47.6 emu/g. The cell survival rates of NiFe₂O₄ and chitosan coated NiFe₂O₄, which were determined by MTT assay, around 85 % and 98.8 %, respectively. The maximum self-heating temperature induced by our specially designed RF-MRI modified L-C circuit was 47.3degC and the frequency and magnetic field product, H ₀f was 1.07 times 10⁹ Am^-1 s^-1