Novel Exchange-coupled Core / Shell Nanoparticles for Advanced Magnetic Hyperthermia

In the search for novel non-harmful cancer treatments, magnetic nanoparticles (MNPs) have shown potential to engage in localized destruction of cancer cells via magnetic hyperthermia—a process that minimizes damage to the patient. It has been found that as the size of the MNP decreases, the heating efficiency drastically decreases. Recently, however, a large improvement in heating efficiency has been reported in exchange-coupling of MNPs between a soft and a hard magnetic material. In this study, we optimized the heating efficiency of exchange-coupled MNPs composed of a soft magnetic core (Fe₃O₄) and a hard magnetic shell (CoFe₂O₄) by tuning both the shape of the nanoparticles and their concentration in solution. The MNPs show high magnetization (~80 emu/g) and superparamagnetic-like behavior at room temperature. We compare the specific absorption rate (SAR) for each set of MNPs and correlate the results to shape distribution and concentration in solution. This study shows that exchange-coupled MNPs for magnetic hyperthermia are promising as route for non-harmful cancer treatment. A new approach for controlling the inductive heat for cancer treatment using a mixture of spheres and cubes is proposed.