A switch-based biosensor for the detection and imaging of Hg(II) in vivo by glutathione functionalized gold nanoparticles

The optical and biological properties of the tunable functionalized gold nanoparticles (GNPs) tuned have been widely used in the sensing applications. GNPs have a strong binding ability to sulfhydryl groups of thiols. Furthermore, thiols is used as mediators to modify functional molecules to adjust their performance, which can be used to detect metal ions in solution. Herein, we demonstrated the 13 nm GNPs were functionalized by glutathione (GSH) and conjugated by rhodamine 6G derivatives (Rh6G2) which can be used to detect of Hg(II) in cells. The detection of Hg 2+ is based on the ion-catalyzed hydrolysis reactions of the spiroamide ring of Rh6G2, leading to a significant change in the fluorescence of GNPs-GSH-Rh6G2 from “OFF” to “ON” due to the triggered release. The designed strategy is an effective tool to detect Hg 2+ . In cytotoxicity experiments, GNPs-GSH-Rh6G2 can penetrate living cells and recognize mercury ions through the fluorescent "ON" form.