Latent Redox Reporter of 4‑Methoxyphenol as Electrochemical Signal Proxy for Real-Time Profiling of Endogenous H2O2 in Living Cells

• Published in: ACS sensors 2019-09, Vol.4 (9), p.2450-2457
• Main Authors: Manibalan, Kesavan, Han, Shuang, Zheng, Yajing, Li, Haifang, Lin, Jin-Ming
• Format: Article
• Language: English
• ISSN: 2379-3694; 2379-3694
• DOI: 10.1021/acssensors.9b01049

Hydrogen peroxide (H2O2) plays a persuasive role in the human cell physiology. Developing an efficient assay platform and a highly sensitive tracking and quantification of H2O2 in a physiological system is crucial to understand the neoplastic changes and/or redox homeostasis of cells. In this study, a novel turn-on latent electrochemical redox probe coupled with electrocatalytic signal amplification strategy is proposed. A custom-made readily available turn-on latent electrochemical probe 4-methoxyphenylboronic acid pinacol ester (4-MPBP) have been designed for the selective detection of endogenous H2O2 in live cells. The electrochemical probe composed of a latent electrochemical reporter (4-methoxy phenol, 4-MP) bearing a recognition unit (boronic acid pinacol ester) for H2O2 sensing. The selective analyte-triggered chemical transformation releases free electrochemical reporter 4-MP. The amount of H2O2 was evaluated electrochemically at glassy carbon electrode (GCE) with a broad detection range of 0.5 μM–1 mM. An amplified signal response of released 4-MP to build a highly sensitive assay tool has been achieved via replacing the GCE transducer electrode with polydopamine@carbonnanotube–molebtinumdisulfie hybrid modified GCE as it delivered an exceptional dynamic detection range of 0.01–100 μM. The innovative blend of electrochemical molecular probe strategy, with electrocatalytic signal amplification technique has delivered outstanding assay performance at trace level sensing of H2O2. Next, we set up a platform for real-time in vivo monitoring of the endogenously produced H2O2 in Caco-2 and MCF-7 cells through spermine–polyamine analogue and phorbol 12-myristate 13-acetate induction in SSAT/PAO gene and protein kinase C, respectively. As expected, the 4-MPBP latent probe coupled with electrocatalytic signal amplification strategy delivered outstanding performance for in situ H2O2 release and tracking over time.