A novel Pd2+-free highly selective and ultrasensitive fluorescent probe for detecting CO-releasing molecule-2 in live cells and zebrafish.

CO-releasing molecule-2 (CORM-2), as a safe donor for releasing CO, has been widely adopted to disclose the physiopathological roles of CO and used as therapeutic drug replacing gaseous CO. The accurate determination of CORM-2 levels in biological systems is central for understanding its safe use as therapeutic agent and the cellular functions of CO. In this paper, a novel fluorescent probe CPD-NB was synthesized, which provided a safe and convenient way for detecting CORM-2 without the requirement of Pd2+ as an additional substrate. It featured a robust fluorescence response to CORM-2 with desirable sensitivity (the detection limit was as low as 4 nM), and showed high selectivity toward CORM-2 over other biologically relevant species. Moreover, with the low cytotoxicity of probe CPD-NB , the visualizations of CORM-2 changes in live cells and zebrafish were also achieved. Thus, we expected that probe CPD-NB could be as an ideal platform for safe and powerful imaging of CORM-2 in biological systems, and may thus promote the progress of CO-related research. Image 1 • The probe could detect CORM-2 without the assistance of Pd2+. • The probe could detect CORM-2 with ultra-sensitivity (detection limit was about 4 nM). • The probe displayed prominent selectivity towards CORM-2. • The probe was successful achieved in imaging the fluctuations of CORM-2 in live cells and zebrafish. [ABSTRACT FROM AUTHOR]