WSP-1

WSP-1 is a highly selective turn-on fluorescent sensor for hydrogen sulfide detection in living cells and plant systems, employing a nucleophilic substitution-cyclization mechanism to rapidly sense both exogenous and endogenous H2S. With λex/λem of 476/516 nm and a quantum yield (ϕ) of 0.003, WSP-1 exhibits a remarkable 130-fold fluorescence increase upon H2S binding, achieving a detection limit of 60 nM and demonstrating excellent selectivity over other biothiols like cysteine and glutathione. WSP1 maintains optimal performance across physiological pH ranges (6-9) and stability even at higher pH values, outperforming its counterpart WSP-5 in highly alkaline conditions. Despite its poor water solubility necessitating the use of organic co-solvents or surfactants, WSP-1′s fast response time, low nanomolar sensitivity, and significant fluorescence enhancement make it a valuable tool for real-time H2S imaging and quantification in complex cellular environments, enabling the study of H2S-mediated signaling pathways and potential therapeutic applications in cardiovascular and neurodegenerative diseases.