"Turn-on" and pinhole-free ultrathin core-shell Au@SiO nanoparticle-based metal-enhanced fluorescent (MEF) chemodosimeter for Hg.

This study reports a metal-enhanced fluorescence chemodosimeter for highly sensitive detection of Hg ions. Silica-coated Au nanoparticles (Au@SiO NPs) with a pinhole-free 4-5 nm shell were synthesized and functionalized with a monolayer of turn-on fluorescent probes. Compared to other organic fluorescent probes suffering from poor biocompatibility and detection limits, this design of a monolayer of turn-on fluorescent probes immobilized on the Au@SiO NPs with a pinhole-free 4-5 nm shell avoids fluorescence quenching and allows the fluorescent probe within the field of the inner Au NPs to experience metal-enhanced fluorescence.