Nanoquencher-Based Selective Imaging of Protein Glutathionylation in Live Mammalian Cells.

Changes in the cellular levels of glutathione (GSH) and protein S-glutathionylation (PSSG) are closely associated with a number of human diseases. Despite recent advances, few thiol-reactive, small-molecule GSH sensors could selectively detect GSH over other endogenous thiols, and none was capable of detecting PSSG in live mammalian cells. By using a dye-loaded mesoporous silica nanoquencher (qMSN) capped with anti-GSH antibody capable of highly selective binding toward GSH and glutathionylated proteins over other molecules, we have successfully developed a fluorescence GSH/PSSG nanosensor, which showed unprecedented selectivity toward PSSG even in the presence of GSH, had amplifiable and programmable fluorescence Turn-ON properties, and could be used to image endogenous PSSG in live mammalian cells under stimulated conditions for the first time.