Nanoparticle redistribution during magnetic nanoparticle hyperthermia: Multi-physics porous medium model analyses

A coupled theoretical framework comprising a suspension of nanoparticles transport in porous media model and a heat transfer model is developed to address nanoparticle redistribution during heating. Nanoparticle redistribution in biological tissues during magnetic nanoparticle hyperthermia is described by a multi-physics model that consists of five major components: (a) a fully saturated porous media model for fluid flow through tissue; (b) nanoparticle convection and diffusion; (c) heat transfer model based on heat generation by local nanoparticle concentration; (d) a model to predict tissue thermal damage and corresponding change to the porous structure; and (e) a nanoparticle redistribution model based on the dynamic porosity and diffusion diffusivity. The integrated model has been used to predict the structural damage in porous tumors and its effect on nanoparticle-induced heating in tumors. Thermal damage in the vicinity of the tumor center that is predicted by the Arrhenius equation increases from 14% with 10 minutes of heating to almost 99% after 20 minutes. It then induces an increased tumor porosity that increases nanoparticle diffusivity by seven-fold. The model predicts thermal damage induced by nanoparticle redistribution increases by 20% in the radius of the spherical tissue region containing nanoparticles. The developed model has demonstrated the feasibility of enhancing nanoparticle dispersion from injection sites using targeted thermal damage.