A General Route to Construct Diverse Multifunctional Fe3O4/Metal Hybrid Nanostructures

Abstract

Multifunctional nanostructures: By using 3-aminopropyltrimethoxysilane as a linker, Au nanoparticles (NPs), Au shells, flowerlike Au/Pt hybrid NPs, and Ag or Au/Ag core/shell NPs could be supported on the surface of superparamagnetic Fe₃O₄ spheres to construct hybrid nanostructures that display near-IR absorption, high catalytic activity towards an electron-transfer reaction, or excellent surface-enhanced Raman scattering activity. The picture shows SEM images of Fe₃O₄ spheres coated with Au shells (top) and with Au/Pt hybrid NPs (bottom). We have developed a simple, efficient, economical, and general approach to construct diverse multifunctional Fe₃O₄/metal hybrid nanostructures displaying magnetization using 3-aminopropyltrimethoxysilane (APTMS) as a linker. High-density Au nanoparticles (NPs) could be supported on the surface of superparamagnetic Fe₃O₄ spheres and used as seeds to construct Au shell-coated magnetic spheres displaying near-infrared (NIR) absorption, which may make them promising in biosensor and biomedicine applications. High-density flowerlike Au/Pt hybrid NPs could be supported on the surface of Fe₃O₄ spheres to construct multifunctional hybrid spheres with high catalytic activity towards the electron-transfer reaction between potassium ferricyanide and sodium thiosulfate. High-density Ag or Au/Ag core/shell NPs could also be supported on the surface of Fe₃O₄ spheres and exhibited pronounced surface-enhanced Raman scattering (SERS), which may possibly be used as an optical probe with magnetic function for application in high-sensitivity bioassays.