Tb-doped iron oxide: bifunctional fluorescent and magnetic nanocrystals

A new class of fluorescent and superparamagnetic bifunctional nanocrystal has been successfully prepared by a facile, non-hydrolytic method. The synthesized Tb-doped gamma-Fe2O3 nanocrystals are highly monodispersed with a diameter of 13 nm, show superparamagnetic behaviour with saturation magnetism strength of 30 emu g(-1), and exhibit photoluminescence at room temperature. The nanocrystals are amine-functionalized to render them water-dispersible and ease of further functionalization by other biomolecules. In vitro cytotoxicity tests indicate that these nanocrystals are non-toxic. Nanocrystals of such bifunctionality are envisioned to have potential as probes in integrated imaging technique, of which at least two imaging modalities ( for example magnetic resonance imaging (MRI) and fluorescence microscopy) are combined to provide enhanced visualization at tissues and cellular levels.