Electromagnetic Heating of Coated Ellipsoidal Gold Nanoparticles in Biological Tissue at Radio Frequencies

Abstract: Radiofrequency heating of gold nanoparticles for use in remote hyperthermia cancer treatment has seenrapidly growing interest in the last decade. While most of the focus has been on studying sphericalnanoparticles, a recent report suggests ellipsoidal particles can significantly increase heat absorption. Inthis manuscript, we therefore study the effects of adding a coating to the nanoparticles. We calculateanalytically the relative absorption ratio of coated ellipsoidal nanoparticles in biological tissue using aneffective medium model, and use this to study the impact on absorption rate for a variety of coatingmaterials. Both the case of a single nanoparticle and the case of a suspension of nanoparticles arestudied. We find that introducing a dielectric coating can increase the absorption rate for particles withlower aspect ratios and lower frequencies, improving the flexibility of particle sizes that can potentiallybe used in treatment.