A Fluorescent ESIPT Probe for Imaging CO-Releasing Molecule-3 in Living Systems.

CO-releasing molecule-3 (CORM-3) has been widely used recently as a convenient and safe CO donor to release exogenous CO in living cells and to study the effects of CO on cellular systems. Accordingly, development of effective methods for detecting and tracking CORM-3 in living systems is of great significance. In this work, a readily available fluorescent probe for detection of CORM-3 was reported for the first time. This probe is based on an excited-state intramolecular proton transfer (ESIPT) dye phthalimide and uses the reducing ability of CORM-3 to convert a nitro group to an amino group, and more importantly, it can be used for rapid, highly selective, and sensitive detection of CORM-3 with a distinct turn-on green fluorescence change in aqueous solution, living cells, and animals, thus providing a useful tool for studying CORM-3 in living systems.