Magnetic-luminescent bifunctional nanosensors

Luminescent-magnetic multifunctional molecularly imprinted polymer (MIP) nanospheres containing luminescent LaVO4:Eu3+ nanocrystals (NCs), magnetic Fe3O4 nanoparticles (NPs), and the recognition sites of template organophosphate pesticides were successfully prepared via a facile and versatile bottom-up self-assembly strategy. Because of the photoluminescence quenching via diazinon molecules (templates) rebinding into the recognition cavities, these composite MIP nanospheres were successfully applied to the selective and direct luminescence detection of diazinon with the assistance of magnetic separation and concentration. The luminescence intensity was proportional to the concentration of diazinon in the range of 0.01-9.0 mu g mL(-1) with the 3 sigma limit of detection (LOD) of 7.1 ng mL(-1). This facile and versatile strategy for the MIP nanocomposites is very easy to be extended to other inorganic/organic multifunctional composite nanospheres and will find great potential application as chemical and biological sensors in aqueous media.