Detecting mitochondrial hypochlorous acid and viscosity in atherosclerosis models via NIR fluorescent probes

The assessment of early atherosclerosis (AS) via fluorescence imaging is crucial for advancing early diagnosis research. Abnormal inflammation biomarkers, including hypochlorous acid (HClO) and viscosity within mitochondria, have been closely linked to the pathogenesis of AS. However, current fluorescent probes predominantly rely on unimodal imaging that targets a single biomarker and lacks mitochondrial specificity, which can result in potential false signal readouts due to the complex intracellular environment. Herein, we report the development of three fluorescence probes (M-1, M-2, and M-3) designed to achieve simultaneous detection and imaging of mitochondrial HClO and viscosity. Spectroscopic analysis revealed these probes exhibit high specificity towards HClO and viscosity, superior sensitivity at sub-nanomolar levels, and rapid response within 2 min. Among them, M-2 demonstrated the best performance in terms of fluorescence emission (extending into near-infrared region) and sensitivity (as low as 0.072 nM), and was selected for biological evaluation. When applied to living cells, the probe M-2 demonstrated high preferential accumulation within mitochondria and a bimodal off-on fluorescence response, allowing the evaluation of mitochondrial HClO and viscosity levels using dual-channel microscopy. With this probe, we effectively monitored abnormal HClO and viscosity levels in early AS mice, providing a highly sensitive and precise tool for early AS diagnosis.