A novel red emission fluorescent probe for monitoring carbon monoxide in living cells and zebrafish.

Carbon monoxide (CO), a gaseous signal molecule, plays a crucial role in biological systems. With the aim of unraveling its biological functions, a novel fluorescent probe for sensing CO was rationally designed and synthesized based on a coumarin derivative fluorophore merging tetrahydroquinoxaline unit and five-membered pyrrolidine. This fluorescent probe demonstrated a large Stokes shift (Δλ = 132 nm), high quantum yield, red emission, high sensitivity and selectivity for CO with remarkable fluorescence turn-on. And the detection limit for CORM-3 is as low as 31.2 nM with the linear range of 0-30 μM. More importantly, this novel probe has been successfully applied to the fluorescence imaging of CO in HepG2 cells and zebrafish, providing a useful approach for the further understanding of the physiological and pathological roles of CO in living systems.