Methylthio-substituted coumarin-based fluorescent probe for highly specific and fast detection of hypochlorite and bioimaging application

Hypochlorite is a kind of endogenously produced reactive oxygen species (ROS) in the human immune system and plays a crucial role in many pathophysiological processes. In this work a novel fluorescent probe derived from 6-methylthio coumarin was designed and synthesised for detection of hypochlorite in acetonitrile/phosphate-buffered saline (MeCN/PBS) (1:1, v/v, pH 7.4) medium. The probe displayed high specificity toward hypochlorite over other ROS analytes, rapid response to hypochlorite within 30 s, and a broad applicable range of pH 3-8. The detection limit was calculated to be 1.48 mu M. Application of this probe for in vitro Hecat cell imaging to detect hypochlorite ions was confirmed. A sensing mechanism based on thioether to sulfoxide oxidation by hypochlorite was proposed and demonstrated. The study presented an effective approach for construction of highly efficient hypochlorite chemosensors from hydrophilic methylthio-substituted coumarins considering their facile access.