Core-shell structured polystyrene (PS)-Fe3O4-graphene oxide (GO) composite nanoparticles were synthesized by sequentially depositing Fe3O4 nanoparticles and GO sheets onto the carboxyl functionalized PS template nanoparticles through electrostatic interactions. Morphologies of the composite nanoparticles were studied by both scanning electron microscopy and transmission electron microscopy, while their structures and chemical components were examined via Fourier transform infrared spectroscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The data confirmed the coexistence of PS, Fe3O4 and GO with a core-shell structure in the composite. The obtained PS@Fe3O4@GO nanoparticles possess excellent magnetic responsivity to externally applied magnetic field and can also form stable dispersion upon the removal of magnetic field. The study on the loading capacity of model molecule Rhodamine B (RhB) indicated the possibilities of using PS@Fe3O4@GO nanoparticles in targeted drug delivery applications. (C) 2012 Elsevier B.V. All rights reserved.