A Study of Magnetic Nanoparticles for Hyperthermia and Their Behavior in Biological Systems and Thermally-Responsive Hydrogels for Drug Delivery

A combination cancer therapy using an environmentally-responsive treatment platform has the potential to improve the efficacy of cancer treatment, while decreasing negative side effects currently associated with such treatments. The proposed platform consists of a thermally-responsive hydrogel embedded with magnetic nanoparticles (MNPs) and an anti-cancer therapeutic agent. The novel design allows for concurrent hyperthermia and chemotherapy treatments, as application of an external magnetic field causes the MNPs to heat, triggering the thermal responsive of the gel. Thermally-responsive poly(N-isopropylacrlamide-co-acrylamide) hydrogels were synthesized and embedded with magnetic nanoparticles. Drug release studies show that increasing the concentration of FePt nanoparticles in a gel has negligible effect on the diffusion of a model drug. CoFe₂O₄ magnetic nanoparticles were synthesized in house and tagged using the red fluorescent dye rhodamine. These MNPs were then introduced to two biological systems: HeLa cancer cells and C. elegans worms. The localization and toxicity of the MNPs were studied. At concentrations below 5 wt% in media, both HeLa cells and the worms, the rhodamine-tagged CoFe₂O₄ showed negligible toxicity. Images obtained from fluorescence microscopy show the nanoparticles internalized in the cytoplasm of HeLa cells and the GI tract of the C. elegans worms.