Recognition of Exogenous and Endogenous Nitroxyl in Living Cells via a Two-Photon Fluorescent Probe.

Nitroxyl (HNO), one electron reduced and protonated form of nitric oxide (NO), plays vital in various biological functions and pharmacological activities, such as mediating β-agonist dobutamine, inhibiting the activity of enzyme and treating cardiovascular diseases. However, the accurate mechanism of HNO in living cells is not thoroughly understood due to lacking of effective methods. In this work, a novel two-photon fluorescent probe TP-HNO was designed and synthesized based on 6-hydroxyl-quinonline-2-benzothiazole derivatives through introducing 2-(diphenylphosphino)benzoate as the ideal HNO recognition unit, which demonstrated the merits of outstanding selectivity, excellent sensitivity (DL 0.19 μM) and rapid response (20 min). In addition, owing to the high cell permeability and low biotoxicity of probe TP-HNO, it was successfully used for the qualitative and bioimaging of exogenous and endogenous nitroxyl concentration fluctuations in living cells via a two-photon laser confocal fluorescence microscopy, respectively, which is of importance for revealing the biological of HNO in the further.