Synthesis and characterization of a new trifunctional magnetic–photoluminescent–oxygen-sensing nanomaterial

Magnetic Fe2O3 nanoparticles coated with SiO2 chemically doped with a Ru(II) complex were prepared using a simple solution based method. Field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) showed that the Fe2O3 nanoparticles with a mean diameter of ~115?nm were successfully coated with Ru(II) complex?chemically doped SiO2 shell with a thickness of ~30?nm. The obtained nanocomposite material showed a strong magnetic response to a varying magnetic field, exhibited the bright red triplet metal-to-ligand charge transfer (3MLCT) emission, and its photoluminescent intensity was sensitive to oxygen concentration. Compared with the Ru(II) complex in silica gels, the Ru(II) complex in the magnetic?optical?oxygen-sensing nanocomposite demonstrated improved thermodynamic stability of emissions. These nanocomposites are also nontoxic and easily conjugated with biomolecules. Their magnetic, photoluminescent and oxygen-sensing properties make them promising candidates for cell separation, biomarkers and optical oxygen sensors, which can measure the O2 concentration in biological bodies.