A novel N-nitrosation-based ratiometric fluorescent probe for highly selective imaging endogenous nitric oxide in living cells and zebrafish

Nitric oxide (NO), a widespread signaling transduction molecule in organism, plays key roles in lots of pathophysiological processes. Aberrant level of NO is closely related to tumors, cardiovascular and cerebrovascular diseases, neurodegenerative diseases and many other diseases. Therefore, sensing NO in cells and in vivo is of great significance for the study of the chemical biology of related diseases. Herein, a novel ratiometric fluorescence probe (AC-SA), in which anthracene carboximide used as fluorophore and secondary amines at the 6th position of the fluorophore severed as recognition moiety is rationally designed to detect NO. The AC-SA can capture NO via N-nitrosation reaction to give obvious fluorescence signal change from red to green based on the intramolecular charge transfer (ICT) mechanism. The AC-SA features striking ratiometric signal (I525/I625), good sensitivity (4.05 nM), high selectivity for sensing NO over various interferents in physiological pH. More important, the AC-SA can be applied to image endogenous NO in Raw 264.7 macrophage cells as well as zebrafish in a ratiometric manner.