Bifunctional Nanoparticles with Magnetization and Luminescence

The Fe3O4@LaF3:Ce3+-Tb3+ bifunctional composite nanoparticles were fabricated with a facile layer-bylayer technology. To get these bifunctional nanocomposites, the as-prepared magnetic (Fe3O4) and luminescent (LaF3:Ce3+-Tb3+) nanoparticles were modified with polyelectrolyte to get positively charged and negatively charged surfaces, respectively. The nanocomposites were then obtained by absorbing the negatively charged LaF3:Ce3+-Tb3+@(PAH/PSS)(2) luminescent nanoparticles onto the positively charged Fe3O4@(PAH/PSS)(2)/PAH magnetic nanocrystal surface through electrostatic interaction. The nanocomposites were characterized with transmission electron microscope (TEM), powder X-ray diffraction (XRD), superconducting quantum interference device (SQUID) magnetometer, Fourier transform infrared (FTIR), and fluorescence technologies. Results indicate that these nanocomposites possess both high magnetization and strong fluorescence, which allows them great potential for bioapplications such as magnetic bioseparation, magnetic resonance imaging (MRI), and drug/gene delivery, simultaneously coupled with fluorescence immunoassays/imaging.