In the present study, we carried out chemical synthesis and characterization of Fe3O4@PEG-Au as a magnetic nanocomposite in aqueous solution by chemical co-precipitation of Fe3+ and Fe2+ ions and encapsulated by poly (ethylene glycol) (PEG) in order to enhancing hydrophilicity, biocompatibility and immobilizing gold ions in the presence of NaBH4 as a reducing agent. Nanostructures were characte...