A new CoFe2O4-Cr2O3-SiO2 fluorescent magnetic nanocomposite

A combined sonochemical co-precipitaion method has been developed for the synthesis of a CoFe2O4-Cr2O3-SiO2 magnetic nanocomposite. The synthesis involved the pre-synthesis of CoFe2O4-Cr2O3 nanoparticles, which were subsequently coated with SiO2 by treatment with tetraethyl orthosilicate. It was observed that the as-prepared CoFe2O4-Cr2O3-SiO2 nanocomposite exhibits photoluminescence properties without the addition of any external fluorescent marker. The fluorescent magnetic nanoparticles (FMNPs) had a typical diameter of 30 +/- 5 nm and a saturation magnetization of 5.1 emu g(-1) at room temperature. This as-prepared nanocomposite was used for staining cultured HeLa cells for fluorescence imaging.