A novel N-alkyhydrazone-based Iridium(III) complex for luminescence imaging of mitochondrial hypochlorous acid in liver injury.

The production of hypochlorous acid (HClO) is well recognized as a biomarker for liver injury, however, existing HClO bioimaging probes often lack specificity. Inspired by the specific recognition of oxime and hydrazide groups for HClO, we developed a novel N-alkyhydrazone moiety as a recognition unit for HClO. This moiety was integrated into an iridium(III) complex, creating a mitochondria-targeted luminescence probe for HClO that leverages the lipophilicity and cationic characteristics of iridium(III) complexes. The probe offers advantages including high specificity over other reactive oxygen species (ROS), rapid response of within 5 min, as well as robust stability. Furthermore, it effectively images both endogenous and endogenous mitochondrial HClO in liver injury-modeled cells and demonstrates excellent penetration capabilities in 3D cell spheres, highlighting its potential for diagnosing liver injury.