Long-wavelength red-emitting ClO− fluorescent probe for visualizing inflammation and drug-induced renal injury

Hypochlorous acid (ClO⁻), a member of the reactive oxygen species (ROS) family, plays an important role in regulating physiological processes and maintaining homeostasis in the body. However, abnormal ClO⁻ levels in the human body have been associated with a variety of pathological conditions, encompassing inflammation and kidney diseases. In this work, we have developed a novel fluorescent probe, RDNClO, specifically tailored for the sensitive detection of ClO⁻. RDNClO was synthesized through modifying N - (7 - (2 - carboxyphenyl) -3- (dimethylamino) - 5,6 - dihydro - 10H - benzo[c]xanthen - 10 - ylidene) - N - ethylethanaminium (RDNOH) with 1-naphthaloyl chloride moiety. Spectroscopic analyses reveal that RDNClO exhibits outstanding performance characteristics, including high selectivity, a rapid response time of <25 s, and an ultra-low detection limit of 3.7 nM. Additionally, RDNClO has demonstrated exceptional capabilities in detecting ClO⁻ in real water samples and rapidly identifying ClO⁻ in environmental samples, utilizing agarose as a carrier. It effectively monitors both endogenous ClO⁻ levels in HeLa cells and exogenous ClO⁻ levels in HEK293T cells. Furthermore, RDNClO has excelled in tracking fluctuations in ClO⁻ levels, including in Escherichia coli, the mouse model of arthritis induced by k-carrageenan, and a mouse model of cisplatin-induced renal injury. The development of RDNClO not only establishes a robust theoretical foundation for investigating the pathogenic mechanisms of renal injury but also presents a promising tool for advancing research in this critical area.