NIR-Activated Water-soluble Molecular Probe Based on Cu(ii) Ion Quenching Mechanisms and Substituted Strategies: For In vitro/In vivo H2S Detection

Human health, environmental contamination, and food safety are tightly associated with hydrogen sulfide (H2S). The safe and highly sensitive monitoring of H2S in tissues, organs, and blood has presented ongoing challenges. Herein, a novel near-infrared (NIR)-activated water-soluble molecular probe, denoted as IR820-TPY-Cu was developed for detecting hydrogen sulfide. This probe is built upon the fluorescent molecule IR820, a derivative of Indocyanine green (ICG). Upon reacting with H2S, IR820-TPY-Cu exhibits active fluorescence (670-750 nm), which is attributed to the Cu (II) ion quenching mechanism and substitution strategy. IR820-TPY-Cu exhibits selectively activated near-infrared fluorescence signal changes, a low detection limit of 0.114 μM, and a rapid in vitro response (3 min) for H2S detection. Moreover, the biocompatible probe IR820-TPY-Cu not only quantitatively monitors H2S in environmental water and various food specimens (red wine, beer, meat, milk, and sweet potato) through colorimetric sensing but also successfully images endogenous and exogenous H2S in living cells, zebrafish, and mice. This research provides a promising approach for monitoring H2S in environmental contamination, ensuring food safety, and studying living systems.