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

Abstract

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.

Two-photon small-molecule fluorescence-based agents for sensing, imaging, and therapy within biological systems

“…A turn-on probe 47 has been developed based on the TP fluorophore 6-hydroxyl-quinoline-2benzothiazole for the detection of HNO (Scheme 16). 25 With probe 47, 2-(diphenylphosphino)benzoate was used as the reactive site towards HNO. In the presence of HNO, probe 47 undergoes an aza-ylide reaction by forming 48, which then undergoes Staudinger ligation to generate 49 (Scheme 16a), resulting in a fluorescence enhancement at 550 nm in PBS buffer solution (Scheme 16b and c).…”

When NO. Is not Enough: Chemical Systems, Advances and Challenges in the Development of NO. and HNO Donors for Old and Current Medical Issues

“…biosynthesis (see below), HNO endogenous production is still poorly understood. This is likely due to the high instability of HNO and the lack of effective detection methods [9c,12] . Nonetheless, there is a series of studies supporting the biological role of HNO, which has been assigned to its reaction with thiol group, metal centers and radicals.…”

A New Phenolate‐Ion‐Type Two‐Photon Near Infrared Fluorophore‐Based Biosensor for High‐Performance Detection of HNO

“…), and some common amino acids (Cys, Hcy, GSH), show negligible interference effect, thus implying the high selectivity of o ‐FDCPO‐P toward HNO. In line with the literature reports, with the aid of HR‐MS (Figure S13) and 1 H NMR (Figure S14) spectral characterizations, the signaling mechanism of o ‐FDCPO‐P to HNO is safely attributed to an intramolecular Staudinger reaction between o ‐FDCPO‐P and HNO (Figure S15).…”