Bifunctional luminescent superparamagnetic nanocomposites of CdSe/CdS-Fe 3O 4 synthesized via a facile method

Herein, we design a facile and green method to synthesize luminescent superparamagnetic nanocomposites with a CdSe/CdS-Fe 3O 4 structure under mild conditions. This approach was performed in the solution phase at ∼90 °C (Fe 3O 4) and 60 °C (CdSe/CdS). Fe 3O 4 nanoparticles, prepared via a simple coprecipitation process, were used as seeds. A new route was designed to induce CdSe/CdS nanoparticle growth around the seeds for preparing bifunctional nanocomposites of CdSe/CdS-Fe 3O 4. In this approach, tri-sodium citrate plays an essential role in guiding and maintaining the structure of the nanocomposites. The fluorescence spectrum and M-H loops indicate that the bifunctional nanocomposites were synthesized successfully. It is proved that these bifunctional nanocomposites could be guided with a magnetic force for in vitro delivery into a human cancer cell line by a fluorescence microscope. The superparamagnetism and the high M s (61.78 emu g -1) of the Fe 3O 4 nanoparticles suggest that these nanocomposites also can be used as a T 2 Magnetic Resonance Imaging (MRI) contrast agent. The MRI images indicate that these bifunctional nanocomposites have potential applications in diagnostics as T 2 MRI contrast agents. © The Royal Society of Chemistry 2012