Bifunctional nanocomposites Fe₃O₄/MOS/CdTe with magnetic and luminescent functionalities

Abstract

A new class of highly fluorescent magnetic core/shell nanoparticles in the submicrometer size range was successfully synthesised by chemically bonding technique. Nanocomposites were prepared via two main steps. The first step involved a facile co-precipitation of ferrous and ferric ions to synthesise superparamagnetic Fe 3 O 4 nanoparticles, which were thereby covered as cores with mannan-oligosaccharides (MOS) shells through the reverse embedding method. The second step involved covalent bondings between MOS coated magnetite particles and luminescent CdTe quantum dots, which were modified by mercaptoacetic acid (MPA). The final nanoparticles were characterised by transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), fluorescence microscope and Fourier transform infrared spectroscopy (FTIR).