Real-time visualization of efficient Nitroxyl (HNO) releasing using fluorescence technique

Direct visualization of Nitroxyl (HNO) release is currently not feasible for all chemical and biological systems, limiting the understanding of its biological and pharmaceutical activities. To address this issue, N-hydroxydansylamide was developed as the first fluorescence turn-off HNO donor that efficiently releases HNO with a fluorescence turn-on probe. Under physiological conditions, the HNO release was observed with a half-life of 19.86 min. The decomposition of N-hydroxydansylamide yielded a fluorescent dansyl-based sulfinate species. Specifically, the concentration of HNO released was successfully monitored based on the fluorescence signal with a limit of detection of similar to 0.55 mu M. Particularly, HNO releasing can be sensed without any depletion of the HNO source. Finally, cellular imaging was also achieved to demonstrate the HNO release derived from N-hydroxydansylamide. Therefore, HNO release profiles in terms of kinetics, dose, and the site can be monitored through real-time fluorometric analysis or imaging-based studies, providing a novel platform to explore HNO biology.