Dielectrophoresis-enabled surface enhanced Raman scattering on gold-decorated polystyrene microparticle in micro-optofluidic devices for high-sensitive detection

Abstract We have developed a method to fabricate higher order surface enhanced Raman scattering (SERS) active structure with gold-decorated polystyrene microparticles (Au/PS microparticles) to serve a wide range of applications in life science and environmental analysis using alternating-current dielectrophoresis (DEP). It is within several tens of seconds to form or gather the SERS—active ‘hot spots’ and analyte. The immobilization of Au/PS microparticles can be demonstrated and qualitatively explained by DLVO and DEP calculation. Our method enables us to detect 4, 4′-bipyridine (4bpy) at 100 pM by an easy operation of in situ SERS platform using fiber-type simple Raman spectrometer. This platform can easily generate SERS-active ‘hot spots’ with SERS enhancement factor ∼ 10 8 in specific region on demand.