Near-infrared mitochondria-targeted fluorescent probe with a large Stokes shift for rapid and sensitive detection of cysteine/homocysteine and its bioimaging application

In this work, tetrahydro-acridine salt hybrid coumarin dyes was designed and developed as a Near-infrared (NIR) fluorescent probe CM for the detection and fluorescent bioimaging of Cys/Hcy. The activated chlorine atom in probe facilitates more efficient nucleophilic substitution reaction, resulting in fast responsive time (3 min toward 3 eq. Cys) and high sensitivity toward Cys with detection limit of 46 nM. More importantly, probe displays “Turn-on” near-infrared fluorescence emission (Emmax: 674 nm) with Large Strokes shift (about 200 nm) toward Cys/Hcy. Furthermore, probe could be used as efficient tool for imaging and detection of Cys/Hcy in mitochondria of living cells and in vivo. This work innovatively proposed a new design strategy for NIR fluorescent probe platform for the detection and fluorescence imaging of bio-thiols. [Display omitted] •A new tetrahydro-acridine salt hybrid coumarin dyes is designed as NIR fluorescent probe CM for detection of Cys/Hcy.•Probe shows remarkable “turn-on” NIR fluorescence change with Large Strokes shift, fast responsive time, high sensitivity and selectivity toward Cys/Hcy.•Probe display low cytotoxicity and mitochondria-targeting ability and can be used to visualize monitor Cys/Hcy changes in living cells and in vivo.