Heating mechanisms in gold nanoparticles at radio frequencies

Gold nanoparticles are under study as a potentially viable mechanism for hyperthermia tumor treatment in two regimes of the electromagnetic spectrum: laser and radio frequency excitation. Gold nanoparticles, nanorods and nanoshells have been applied with visible laser sources that excite the particles at or near their plasmon resonance frequency, and this mechanism has been well studied. The physical processes that describe the experimentally observed heating at radio frequencies (13.56 MHz) are not as well understood. Differing results have been reported in semi-solid phantom materials and liquid phase suspensions. This numerical modeling study was undertaken to inspect the relative importance of several candidate physical processes.