Stable Magnetic Hot Spots for Simultaneous Concentration and Ultrasensitive Surface-Enhanced Raman Scattering Detection of Solution Analytes
journal contributionposted on 21.06.2012, 00:00 by Yongxing Hu, Yugang Sun
A simple and robust strategy is reported in this Article for the synthesis of stable magnetic surface-enhanced Raman scattering (SERS) hot spots in superparamagnetic, raspberry-shaped, mesoscopic gold particles that are composed of superparamagnetic Fe3O4 cores, amorphous SiO2 mediation shells, and outer individual Au nanoparticles. The average interparticle gaps between the Au nanoparticles can be finely tuned by controlling the synthesis conditions, resulting in the formation of adequate SERS hot spots. The magnetic cores provide the capability to concentrate solution analytes adsorbed on the surfaces of the composite particles with the assistance of an external magnetic field, leading to ultrasensitive SERS detection of target species with concentration as low as femtomolar.