A Boronic Acid-Based Ratiometric Fluorescent Probe for Selective Detection of Hydrogen Peroxide

Hydrogen peroxide (H₂O₂) plays a key role in diverse physiological and pathological processes, including immune responses, cancer progression and aging. Herein, we report a novel ratiometric fluorescent probe (CBN) for H₂O₂ detection, synthesized via a one-step condensation reaction between 3-cyano-7-hydroxycoumarin and 4-(bromomethyl)benzeneboronic acid pinacol ester. The probe exhibited excellent selectivity and sensitivity toward H₂O₂ (limit of detection [LOD] = 0.71 µM) with minimal interference from competing ions. Furthermore, CBN demonstrated application in exogenous H₂O₂ detection in living HepG2 cells, highlighting its potential for biomedical research.