Selective fluorescence detection of nitroxyl over nitric oxide in buffered aqueous solution using a conjugated metallopolymer

A bithiophene-substituted poly(p-phenyleneethynylene) derivative (CP1) having water-solubilizing side chains was prepared and characterized. Copper(II)-induced quenching of CP1 emission was quantified in H2O, MeCN/H2O (90:10), and pH 7.4, 50 mM HEPES, 100 mM KCl buffer. In buffer, treatment of CP1-Cu(II) with nitroxyl (HNO) produces an immediate 2.1-fold increase in emission, whereas exposure to NO(g) effects no fluorescence restoration. The ability to distinguish HNO from NO chemically at physiological pH represents a productive step towards the development of selective, fluorescence-based biosensors for HNO.

Graphical abstractA bithiophene-substituted poly(p-phenyleneethynylene) derivative (CP1) having water-solubilizing side chains was prepared and characterized. Copper(II)-induced quenching of CP1 emission was quantified in H2O, MeCN/H2O, and pH 7.4 HEPES/KCl buffer. In buffer, treatment of CP1-Cu(II) with nitroxyl (HNO) produces an immediate 2.1-fold increase in emission, whereas exposure to NO(g) effects no fluorescence restoration.Figure optionsDownload full-size imageDownload as PowerPoint slide