A mitochondria-targeted fluorescent probe for imaging of endogenous carbon monoxide in living cells

Carbon monoxide (CO), a vital gasotransmitter, plays critical functions in many physiological processes. Mitochondrial CO is closely related to mitochondrial respiration, thus the detection and imaging of mitochondrial CO in living cells is very important and has attracted much attention recently. In this paper, we developed a hemicyanine-based off-on fluorescent probe, CO-H1, which was used for monitoring endogenous mitochondrial CO levels in living cells. After reacted with CO in the presence of PdCl2, the fluorescence of CO-H1 was enhanced notably, accompanied by a significant red shift of absorption. CO-H1 exhibits low cytotoxicity, high sensitivity (detection limit of 0.048 mu M), and good selectivity for CO. When incubated with living cells, probe CO-H1 mainly entered the mitochondria. CO-H1 was successfully applied to imaging the exogenous/endogenous mitochondrial CO in living cells, suggesting its potential application for further studying the biological functions of mitochondrial CO in living cells.

Automated summary

In this study, a hemicyanine-based off-on fluorescent probe, CO-H1, was developed for monitoring endogenous mitochondrial CO levels in living cells. CO-H1 exhibited significant fluorescence enhancement and red shift of absorption upon reaction with CO in the presence of PdCl2. The probe demonstrated low cytotoxicity, high sensitivity (detection limit of 0.048 μM), and good selectivity for CO. CO-H1 mainly targeted the mitochondria in living cells and successfully imaged exogenous/endogenous mitochondrial CO, indicating its potential for further studying the biological functions of mitochondrial CO in living cells.