Hybrid Polyelectrolyte/Fe₃O₄ Nanocapsules for Hyperthermia Applications

We validated here the applicability to hyperthermia treatment of magnetic nanocapsules prepared by the sequential layer-by-layer adsorption of polyelectrolytes and magnetic, Fe3O4 nanoparticles. For the shell preparation around a nanodroplet liquid core, biocompatible polyelectrolytes were used: poly l-lysine as the polycation and poly glutamic acid as the polyanion. The hyperthermia effect was demonstrated by applying the radio frequency (rf) magnetic field with maximum fields H up to 0.025 T and frequencies up to 430 kHz; we found sizable heating effects, with a heating rate up to 0.46 °C/min. We also found effects of irradiation on capsules' morphology that indicated their disruption, thus suggesting their potential use as nanocarriers of drugs that can be locally released on demand. Therefore, these magnetically responsive nanocapsules could be a promising platform for multifunctional biomedical applications such as the controlled release of pharmaceuticals in combination with hyperthermia treatment.