Fluorescence-Enhanced Sensing of Hypochlorous Acid Based on 2-Pyridylthiazole Unit

Hypochlorous acid, being one of reactive oxygen species (ROS), is essential to protect the body against invasion of pathogens. Excess of hypochlorous acid (HOCl) is believed to be in tight connection with various inflammation-related diseases. It remains a challenge to detect the ROS in physiological conditions (aqueous buffer and neutral pH) with selectivity. In the presented paper, we have synthesized a ferrocence-modified pyridylthiazole derivatives, 1,4-di{5-[(4'-ferrocenyl-2'-(4"-pyridyl)]thiazinyl}benzene (DFPT). Only HOCl could turn-on the fluorescence of DFPT with enhanced emission at 465 nm. Compared to the other reported HOCl sensors, DFPT could selectively detect HOCl with rapid response (< 60 s) in the aqueous buffer (pH = 7.0). The detection limit at pH = 7.0 was 0.7 μM according to the titration experiment.