Magnetically responsive biopolymeric multilayer films for local hyperthermia

We present a proof of concept on the use of thermomagnetic polymer films (TMFs) as heating devices for magnetic hyperthermia in vitro. The TMFs were prepared through spray assisted layer-by-layer assembly of polysaccharides and magnetic iron oxide nanoparticles, yielding an alternate magnetic-polymer multilayer structure. By applying a remote alternating magnetic field (AMF) (f = 180 kHz; H = 35 kA m^-1) we increased the temperature of the TMFs in a thickness-dependent way, up to 12 °C within the first 5 minutes. To test our films as heating substrates for magnetic hyperthermia, a series of in vitro experiments were designed using human neuroblastoma SH-SY5Y cells, known by their tolerance to thermal stress. The application of two AMF cycles (30 minutes each) showed that the exogenous magnetic hyperthermia resulted in an 85% reduction of cell viability. This capacity of the TMFs of hyperthermia-mediated cell killing using a remote AMF opens new options for the treatment of small and superficial tumor lesions by means of remotely-triggered magnetic hyperthermia.