Surface-enhanced Raman scattering from magneto-metal nanoparticle assemblies

Binary nanoparticles composed of a superparamagnetic Fe3O4 core and an Au nanoshell (Fe3O4@Au) were prepared via a simple co-precipitation method followed by seed-mediated growth process. The nanoparticles exhibited functions of both fast magnetic response and local surface plasmon resonance. The Fe3O4@Au nanoparticles were used as probes for surface-enhanced Raman scattering (SERS) using p-thiocresol (p-TC) as reporter molecule. With the ability of analyte capture and concentration magnetically, the Fe3O4@Au nanoparticles showed significant SERS properties with excellent reproducibility. Under non-optimized conditions, detection limit as low as 4.55 pM of analyte can be reached using Fe3O4@Au nanoparticle assemblies, which excel remarkably the cases with traditional Au nanoprobes. (C) 2012 Elsevier B.V. All rights reserved.