Dipole-interaction mediated hyperthermia heating mechanism of nanostructured Fe3O4 composites

• Heating characteristics and DC magnetization measurements were carried out for two different Fe3O4 nanoparticle arrangements.
• Hysteresis heating was found to be responsible for dominant heating mechanism in AC field at 13.56 MHz.
• The PAA coated single nanoparticle system was found to be more efficient heat source than the polystyrene (PS)/Fe3O4 based composites.
• Dipole–dipole interaction was found responsible for the reduced magnetic hyperthermia effect.

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 (~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.