Dipole-interaction mediated hyperthermia heating mechanism of nanostructured Fe3O4 composites

A correlation between the DC magnetization and hyperthermia heating rate in high frequency magnetic fields was established for two distinctively different magnetic nanoparticle (MNP) systems: (1) polystyrene (PS)/Fe3O4 based composites, consisting of 10 nm diameter Fe3O4 nanoparticles embedded in the matrix of polystyrene (PS) spheres (similar to 100 nm), and (2) similar Fe3O4 nanoparticles coated with polyacrylic acid (PAA) and dispersed in water. Due to physical confinement of Fe3O4 nanoparticles in the former, the PS/Fe3O4 composite exhibited much lower magnetic hyperthermia heating compared to the latter. The reduced magnetic hyperthermia heating in the polystyrene (PS)/Fe3O4 based composites was found to be associated with strong dipolar interactions. (C) 2014 Elsevier B.V. All rights reserved.