Rapid and sensitive detection of nitric oxide by a BODIPY-based fluorescent probe in live cells: glutathione effects.

Nitric oxide (NO) is an important signaling molecule involved in various physiological and pathological processes. The effects of NO depend on its concentration, and the spatial and temporal constraints of the cell microenvironment. Meanwhile, NO can react with some biomolecules such as biothiols, leading to a short biological lifetime. Thus, it is very crucial to establish a real-time visualization method for monitoring NO levels. In this work, we have developed a fluorescent probe, RBA, for NO, with a 3-extended BODIPY as a fluorophore and a secondary amine as the active site. The probe RBA can quickly sense NO (∼10 s) in aerobic solutions to generate a fluorescent N-nitrosamine (RBA-NO, Φf = 0.87) due to blocking of the photoinduced electron transfer (PET) process from the secondary amine to the BODIPY core. This sensing reaction displays high sensitivity (LOD = 10 nM) and high selectivity for NO over relevant analytes except some reducing reagents including biothiols, and a remarkable interference effect is observed ascribed to a competitive reaction with biothiols. Furthermore, the exo- and endogenous detection of NO in live cells and zebra fish was achieved, and it was demonstrated that glutathione (GSH) weakens drastically the fluorescence response by cell-imaging experiments. These results imply that the colorimetric and fluorescence response of the chemosensor for NO depends on the levels of both NO and GSH in environments.