The development of a hemicyanine-based ratiometric CO ﬂuorescent probe with long emission and its applications for imaging CO in vitro and in vivo
Carbon monoxide (CO) is a sort of significant gasotransmitter and related to various physiological and pathological behaviours. Due to the prospects of utilization in living biological systems, a series of fluorescent probes for detecting CO in living organisms have been developed. However, some of them are complex synthesis, unstable and not all of the probes are proper for biological CO tracking because of the short wavelength emission. Here we report a novel ratiometric CO fluorescent probe (Hcy-CO) with long wavelength emission by simple synthesis. The probe exhibits ideally response speed (<10s), long wavelength emission (600 nm), high sensitivity and selectivity towards CO. According to the results tested on HeLa and RAW264.7 cells, and zebrafish, Hcy-CO shows ability for in vitro and in vivo imaging due to its above-mentioned distinct features. Overall, Hcy-CO could be as a useful molecular tool for imaging CO with long wavelength emission in vitro and in vivo.