Magnetic Nanoparticles with High Specific Absorption Rate at Low Alternating Magnetic Field

This paper describes the synthesis and properties of a new type of magnetic nanoparticle (MNP) for use in the hyperthermia treatment of tumors. These particles consist of 2-4 nm crystals of gamma-Fe2O3 gathered in 20-40 nm aggregates with a coating of carboxymethyl-dextran, producing a zetasize of 110-120 nm. Despite their very low saturation magnetization (1.5-6.5 emu/g), the specific absorption rate (SAR) of the nanoparticles is 22-200 W/g at applied alternating magnetic field (AMF) with strengths of 100-500 Oe at a frequency of 160 kHz.