A facile approach to fabricate water-soluble Au-Fe ₃O ₄ nanoparticle for liver cancer cells imaging

Au-Fe ₃O ₄ nanoparticles were widely used as nanoplatforms for biologic applications through readily further functionalization. Dopamine (DA)-coated superparamagnetic iron oxide (SPIO) nanoparticles (DA@Fe ₃O ₄) have been successfully synthesized using a one-step process by modified coprecipitation method. Then 2-3 nm gold nanoparticles were easily conjugated to DA@Fe ₃O ₄ nanoparticles by the electrostatic force between gold nanoparticles and amino groups of dopamine to afford water-soluble Au-Fe ₃O ₄ 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.