Synthesis of Fine-Tuning Highly Magnetic Fe@FexOy Nanoparticles through Continuous Injection and a Study of Magnetic Hyperthermia

Core@shell Fe@FexOy nanoparticles (NPs) have the potential to be promising tools for many applications, thanks to their combination of an iron core, with a high magnetic moment and an iron oxide shell which could protect the core from oxidation. However, the deterioration of NPs structure can lead to the shrinking of the core and the hollowing of the structure, diminishing the magnetic properties. The ability to retain the iron core under biomedically compatible conditions is desirable for many applications. In this paper, we have developed a synthetic method to produce core@shell α-Fe@FexOy NPs with tunable sizes and evaluated the retention of the stable magnetic α-Fe core upon exposure to air and after ligand exchange and its resulting effect on the magnetic hyperthermia. In particular, using a continuous injection of the precursor, we were able to finely tune the final size of the core@shell NPs producing four samples with average sizes of 12, 15, 18, and 20 nm. The structural properties of the particl...