A Turn-On Fluorescence Probe for Rapidly Sensing Exogenous and Endogenous Hydrogen Peroxide in Living Cells

Abstract

Monitoring abnormal changes in hydrogen peroxide (H₂O₂) levels in mammalian cells is essential to understanding its physicochemical functions in biological systems. Generally, H₂O₂ fluorescent probes used for intracellular monitoring are limited to the long response time and low sensitivity. Herein, the 1,8-naphthimide-based fluorescent probe (NPB) with excellent photostability was confirmed to be an H₂O₂ specific probe due to the oxidation of borate ester to phenol. Compared with previously reported molecular probes, NPB displayed improved performance in H₂O₂ detection, such as excellent photostability, good anti-interference, high selectivity, fast response (10 s), and low detection limit (15 nM). Furthermore, the most outstanding advantage of the as-prepared NPB was mitochondrial-targeting ability with a Pearson's colocalization coefficient of 0.91. Meanwhile, the probe NPB with excellent biocompatibility was successfully utilized for imaging exogenous and endogenous H₂O₂ in living cells. The sensing mechanism of NPB to H₂O₂ was further carefully demonstrated and proposed to involve the oxidation of borate to phenol by H₂O₂. We anticipated that the as-prepared NPB should have broad application in chemical analysis and reveal the physiological function of H₂O₂ in vivo.