Novel Turn-on Fluorescent Probe for Endogenous Peroxynitrite Detection Based on Selective Oxidation of Nitrobenzoyl Formate Ester

Abstract

A turn-on fluorescent probe (EASHC-NO2) is designed for endogenous peroxynitrite (ONOO⁻) detection. The probe contains a fluorophore with intramolecular charge transfer (ICT) effect and a selective sensing site containing nitro groups to suppress fluorescence. By using the oxidizing property of ONOO⁻, the dicarbonyl structure in nitrobenzoyl formate ester is oxidized and degraded, thereby eliminating the nitro structure in the probe and achieving turn on fluorescence. The strong ICT effect ensures that the fluorophore has a sufficiently large emission redshift to 626 nm, with a large Stokes shift of 90 nm. Probe EASHC-NO2 exhibits a low detection limits to 16 nM, high sensitivity and high stability within the physiological range. The living cell studies show that the probe can effectively detect both exogenous and endogenous ONOO⁻, indicating that probe EASHC-NO2 has potential value in practical biological applications.