Work

A turn-on fluorescent probe for selective detection of peroxynitrite via electrophilic addition mechanism and cellular imaging

Year: 2026

Type: article

Abstract: Peroxynitrite (ONOO - ), a key pathological mediator, demands fast and reliable detection. Herein, we report TADBI, a turn-on fluorescent probe based on triphenylamine-benzo indole framework. TADBI shows a rapid (< 50 s) colorimetric change from violet to colourless, and a strong fluorescence enhancement at 440 nm upon ONOO - sensing, with a low detection limit of 71.8 nM. DFT studies reveal that ONOO - - induced disruption of π- conjugation switches the probe from a non-emissive locally excited state to an ICT state, supressing non-radiative decay enabling fluorescence enhancement. The large Stokes shift reduces excitation-emission overlap and re-absorption, thereby minimizing self-absorption, enhancing signal-to-noise ratio, and clearer biological imaging. Mechanistic studies using ¹H NMR and HRMS revealed that ONOO - undergoes electrophilic addition to the C = C bond, rather than oxidative cleavage, and activating fluorescence. Live-cell imaging in HeLa cells confirm efficient and selective detection of both exogenous and endogenous ONOO - , highlighting TADBI as a promising probe for real-time biological imaging.

Source: Discover Sensors

DOI: 10.1007/s44397-026-00044-2

Authors: Raguraman Lalitha, Ramanathan Rakesh Kumar, Yueh-Hsun Lu, Shu Pao Wu, Sivan Velmathi

Institutions: National Institute of Technology Tiruchirappalli, National Yang Ming Chiao Tung University

Language: English

Topic: Molecular Sensors and Ion Detection

Subfield: Spectroscopy

Field: Chemistry

Domain: Physical Sciences

Open Access status: diamond

Funders: Human Resource Development Centre, Council of Scientific And Industrial Research, Council of Scientific and Industrial Research, India, Human Resource Development Group

Awards: G3506817841, G3544487857, G6717287354