Rational design of stable near-infrared cyanine-based probe with remarkable large Stokes Shift for monitoring Carbon monoxide in living cells and in vivo

Carbon monoxide (CO) is an important kind of gasotransmitter associated closely with pathogenesis of inflammation and detection of CO in living systems is of great attraction in recent years. To data, accurate fluorescent detection of CO in vivo is still challenging. In this study, we reported for a new simple NIR fluorescent probe CO–B with stable allyl ether as the specific CO-reactive site. The detection mechanism of this probe has been proven through the rearrangement of conjugated π-electron system. CO–B featured large Stokes shift (135 nm), low toxicity, good sensitivity (detection limit of ∼110 nM) and selectivity for CO detection. CO–B successfully served as an indicator for imaging CO in Heme-stimulation inflammation model. Finally, CO–B was also employed for in vivo imaging CO in living mice with low background interference. All together, probe CO–B was potentially valuable as a promising tool for monitoring and tracking CO in preclinical applications.