Selective fluorescent probes for live-cell monitoring of sulphide

Abstract

Aqueous sulphides, including hydrogen sulphide, have important roles in biological signalling and metabolic processes. Here we develop a selective sulphide-trapping strategy involving sulphide addition to an aldehyde; the resulting hemithioacetal undergoes a Michael addition with an adjacent unsaturated acrylate ester to form a thioacetal at neutral pH in aqueous solution. Employing this new strategy, two sulphide-selective fluorescent probes, SFP-1 and SFP-2, were synthesized on the basis of two different fluorophore templates. These probes exhibit an excellent fluorescence increase and an emission maximum shift (SFP-1) in response to Na 2 S and H 2 S in a high thiol background as found under physiological conditions. We show the utility of the probes for the selective detection of sulphides, and the capacity of our probes to monitor enzymatic H 2 S biogenesis and image free sulphide in living cells. © 2011 Macmillan Publishers Limited. All rights reserved.