A Facile Approach to Fabricate Water-soluble Au-Fe3O4 Nanoparticle for Liver Cancer Cells Imaging

Au-Fe3O4 nanoparticles were widely used as nanoplatforms for biologic applications through readily further functionalization. Dopamine （DA）-coated superparamagnetic iron oxide （SPIO） nanoparticles （DA@Fe3O4） have been successfully synthesized using a one-step process by modified coprecipitation method. Then 2--3 nm gold nanoparticles were easily conjugated to DA@Fe3O4 nanoparticles by the electrostatic force between gold nanoparti- cles and amino groups of dopamine to afford water-soluble Au-Fe3O4 hybrid nanoparticles. A detailed investigation by dynamic light scatting （DLS）, transmission electron microscopy （TEM）, fourier transform infrared （FT-IR） and X-ray diffraction （XRD） were performed in order to characterize the physicochemical properties of the hybrid nanoparticles. The hybrid nanoparticles were easily functionalized with a targeted small peptide A54 （AGKGTPSLETTP） and fluorescence probe fluorescein isothiocyanate （FITC） for liver cancer cell BEL-7402 imaging. This simple approach to prepare hybrid nanoparticles provides a facile nanoplatform for muti-functional derivations and may be extended to the immobilization of other metals or bimolecular on SPIO surface.