Toward rapid and selective detection of hypochlorous acid in pure aqueous media and its application to cell imaging: BODIPY-derived water-soluble macromolecular chemosensor with high sensitivity

Hypochlorous acid (HOCl), an important reactive oxygen species (ROS), plays a central role in many vital biological processes. Here a tailor-made boron dipyrromethene (BODIPY)-based polymeric probe (P1) incorporating aldoxime units was synthesized, targeting both colorimetric and fluorometric HOCl detection in pure aqueous media. On treatment with HOCl, P1 showed a distinct color change from pink to yellow and turnon fluorescence with high sensitivity with an extremely low limit of detection (LOD = 17 nM). P1 also exhibited excellent selectivity over other competitive reactive oxygen and nitrogen species, with outstanding hydrolytic and photolytic stability, demonstrating its suitability for in-field applications. Such rapid, selective, and sensitive HOCl detection by P1 originated from oxidative dehydrogenation of BODIPY-aldoxime units to form nitrile oxide. Moreover, P1 showed low cytotoxicity and was successfully employed for imaging exogenously produced HOCl in human liver cancer cell line HepG2. Given its high water solubility, the newly designed polymeric probe enabled rapid, selective, and sensitive HOCl detection in pure aqueous media.