Elemental iron, sometimes called zero-valent iron or Fe(0), has better magnetic susceptibility than iron oxides, which suggests excellent potential for biomedical applications. Thus far, among the magnetic nanomaterials, iron oxides have been found to be biocompatible and are being extensively applied in nanomedicine research as well as clinical application. This type and other magnetic nanoparticles have attracted significant attention in the discipline of nanomedicine because their ideal size and magnetic characteristics suggest considerable potential as novel theragnostic (i.e., combined therapeutic-and-diagnostic) agents. One promising anti-cancer material is nanoscale iron. It is of genuine clinical value to develop biocompatible anti-cancer drugs that selectively target cancer cells but have lower toxicity to healthy cells and organs. One of the pressing healthcare needs worldwide is the development of cancer treatments that have greater efficacy and reduced toxicity. However, we identified that the anti-cancer properties of nanoparticles can be well preserved under argon or, better still, liquid nitrogen storage for six months and at least one year, respectively. These changes cause the loss of the particles’ anti-cancer effects. We found that dried and reconstituted nanoparticles, or nanoparticles within cells, decompose into irregular fragments of γ-F 2O 3 and agglomerated gold clumps. To determine the reasons for this diminished anti-cancer activity, we examined nanoparticles at different preparation and storage stages by means of transmission electron microscopy combined with and energy-dispersive X-ray spectroscopy, along with X-ray diffraction analysis and cell viability tests. In our previous studies, gold-coated iron nanoparticles showed cancer selective anti-cancer properties in vitro and in vivo but were found to gradually lose that activity with storage or “ageing”. Finding a cancer-selective drug that avoids damaging healthy cells and organs is a holy grail in medical research.

Iron core shell nanoparticles