Enhanced Magnetic Hyperthermia in Iron Oxide Nano-Octopods: Size and Anisotropy Effects

Abstract

Magnetic hyperthermia treatment requires biocompatible magnetic nanoparticles with improved heating capacities to become a viable clinical method for cancer treatment. Although small superparamagnetic iron oxide nanoparticles under low fields have been favored (linear response theory regime), these nanoparticles present a series of limitations, including relatively low heating efficiency (specific absorption rate or SAR), that need to be overcome to make magnetic hyperthermia an efficient clinical application. We here show that by modifying the shape into deformed cubes (octopods) and tuning their size, their SAR can be greatly increased up to 70% (from 140 to 240 W/g). By using nonhydrolytic thermal decomposition, we have obtained highly crystalline monodisperse nano-octopods for different sizes (17–47 nm), and their heating response has been extensively studied in a wide range of AC fields (20–800 Oe) using combined calorimetric and AC magnetometry experiments. Our results consistently reveal that at AC...