Facile Gold-Coated Maghemite Nanoparticles Fabrication

Abstract

The maghemite (γ-Fe ₂ O ₃ ) nanoparticles were obtained via high temperature pyrolysis with the precursor of magnetite that was synthesized via chemical coprecipitation. Then the (3-aminopropyl) triethoxysilane (APTES) was used for the surface functionalization of γ-Fe ₂ O ₃ nanoparticles. Finally the gold-coated maghemite (γ-Fe ₂ O ₃ /Au) nanoparticles are prepared via sonochemical synthesis of a solution mixture of hydrochloroauric acid (HAuCl ₄ ) and APTES-coated γ-Fe ₂ O ₃ nanoparticles with further drop-addition of sodium citrate. The γ-Fe2O3/Au nanoparticles were characterized by X-ray powder diffraction (XRD), ultraviolet-visible spectroscopy (UV-Vis), transmission electron microscopy (TEM) and superconducting quantumn inteference devices (SQUID). The γ-Fe ₂ O ₃ /Au nanoparticles with double properties of magnetism and colloidal gold may have intensive application in immunology, biochemistry, biomedical and molecular biology.