BODIPY-Based Ratiometric Fluorescent Sensor for Highly Selective Detection of Glutathione over Cysteine and Homocysteine

TLDR

The authors present a ratiometric fluorescent sensor based on monochlorinated BODIPY for highly selective detection of glutathione (GSH) over cysteine (Cys) and homocysteine (Hcy). The sensor functions through thiol–halogen substitution: GSH thiolates replace the chlorine to form a sulfur‑substituted BODIPY, whereas Cys/Hcy amino groups further displace the thiolate to generate an amino‑substituted BODIPY, allowing ratiometric fluorescence in living cells. The distinct photophysical properties of the sulfur‑ and amino‑substituted BODIPY derivatives enable clear discrimination of GSH from Cys and Hcy.

Abstract

We report a ratiometric fluorescent sensor based on monochlorinated BODIPY for highly selective detection of glutathione (GSH) over cysteine (Cys)/homocysteine (Hcy). The chlorine of the monochlorinated BODIPY can be rapidly replaced by thiolates of biothiols through thiol–halogen nucleophilic substitution. The amino groups of Cys/Hcy but not GSH further replace the thiolate to form amino-substituted BODIPY. The significantly different photophysical properties of sulfur- and amino-substituted BODIPY enable the discrimination of GSH over Cys and Hcy. The sensor was applied for detection of GSH in living cells.