NIR chemosensor for rapid tracking and evaluating hypochlorous acid level within biosystem and inflammatory DILI models.

Hypochlorous acid, one of the commonly available active ROS species that regulate metabolism and complex biosystem. It is also a crucial hazardous oxidative waste component in the environment linked to inflammation and hepatic damage. Thus, the strategic development of fluorescence chemosensor exhibiting elevated selectivity and sensitivity continues to be a primary research emphasis for hypochlorous acid detection. This paper presents the design and synthesis of a novel near-infrared (NIR) fluorescent probe, HY720, for the selective detection of hypochlorous acid. The probe demonstrates a rapid fluorescence response (within 20 s) upon interaction with hypochlorous acid, accompanied by a notable emission shift at 591 nm. HY720 has remarkable selectivity for diverse reactive oxygen species (ROS), reactive nitrogen species (RNS), metal ions, amino acids, and physiologically significant thiols, alongside a low detection limit of 80 nM. The probe exhibits consistent fluorescence characteristics across a wide pH spectrum, confirming its appropriateness for physiological and environmental applications. HY720 has been effectively utilized to visualize hypochlorous acid in living cells, zebrafish. Furthermore, in liver injury mouse model, we observed an increase of the hypochlorous acid level by comparing the fluorescence signal. All of the findings demonstrated the probe's excellent biocompatibility, tissue permeability, and practical utility. These findings confirm HY720 as a promising small-molecule chemical agent for precise and real-time detection of hypochlorous acid in biological and physiological related contexts.