Metal-enhanced fluorescence of OG-488 doped in Au@SiO2 core-shell nanoparticles

Monodisperse Au-core silica-shell (Au@SiO2) nanoparticles demonstrated a great potential for the application of metal-enhanced fluorescence (MEF). The silica shell was doped with a novel fluorophore, Oregon Green 488-isothiocyanate (OG-488). The fluorescence of OG-488 was enhanced by Au nanoparticle core, while the silica shell was used to control the distance between OG-488 and Au surface to alleviate fluorescence quenching. The fluorescence enhancement by Au@SiO2 nanoparticles was investigated by varying SiO2 shell thickness (from 15 nm to 50 nm) and Au core diameter (40 nm, 60 nm and 80 nm). Compared with OG-488 doped silica spheres without Au core, the Au@SiO2 nanoparticles maximally gave 35-fold stronger fluorescence emission.