Fabrication and estimation of Au-coated Fe3O4 nanocomposite powders for the separation and purification of biomolecules

Au and Fe3O4 nanoparticles were prepared by reduction and coprecipitation methods. The Au/Fe3O4 nanocomposite particles were prepared through the control of the surface charges, and glutathione (GSH) of a thiol group was used as a biomolecule. GSH immobilization onto Au/Fe3O4 was accomplished by simply mixing process. The nanoparticles were characterized by UV–vis spectroscopy: X-ray diffraction, transmission electron microscopy and vibrating sample magnetometry. The amount of immobilized GSH on the Au/Fe3O4 increased with increasing amount of coated Au nanoparticles. The possibility of Au/Fe3O4 nanocomposite particles for the application to the separation and purification of biomolecules by magnetic field was confirmed.