A novel photoactivatable coumarin-based fluorescent “turn-on” probe: Synthesis and applications for H<inf>2</inf>S detection in living cells and zebrafish models

Abstract

A new photoactivatable “TURN-ON” fluorescent probe for H₂S detection was designed based on a tribromocoumarin scaffold, and successfully implemented through O-sulfonylation between a 3,6,8-tribromo-7-hydroxy-4-methylcoumarin (TBC) fluorophore and a dabsyl quencher. The H₂S-responsive strategy of the dabsyltribromocoumarin (Dab-TBC) probe is initiated via light-induced thiolysis of a sulfonate ester. This probe demonstrated excellent sensitivity and great stability towards H₂S detection under UV light irradiation, with no interference from other analytes, achieving a detection limit (LoD) of 1.61 μM. Importantly, Dab-TBC exhibited superb membrane permeability and showed great potential for visualizing H₂S levels in HeLa cells and zebrafish models, with no toxicity confirmed by in vivo toxicity studies in zebrafish embryos.