Screening drug-induced liver injury through two independent parameters of lipid droplets and peroxynitrite with a π-extended coumarin-based NIR fluorescent probe

Drug -induced liver injury (DILI) or hepatotoxicity is a significant concern for public health. However, relying on a single biomarker for early DILI diagnosis poses a high risk of false positives. In this study, we reported a nearinfrared fluorescent probe ( BCOU-S ), which enables independent visualization of LDs status and ONOO - fluctuations. BCOU-S was constructed by combining a pi-extended coumarin core as the NIR fluorophore and a methyl thioether group as the ONOO - recognition site. BCOU-S could emit 655 nm NIR fluorescence excited at 518 nm, with a low detection limit of 27 nM and a large Stokes shift of 137 nm. The response mechanism to ONOO - was confirmed by molecular orbital density function theory (DFT) and time -dependent DFT (TD-DFT) calculations. BCOU-S monitors LDs status through co -localization, oleic acid (OA) incubation, and starvation induction experiments. It sensitively distinguishes subtle changes in ONOO - induced by different drugs in DILI cell models. In the acetaminophen (APAP)-induced DILI model, BCOU-S reveals significant LDs accumulation and increase in ONOO - levels, establishing a clear time -effect and dose -effect relationship. Simultaneously monitoring ONOO - levels and LDs accumulation, BCOU-S proves to be a more sensitive and effective tool for early DILI prevention, effectively avoiding false positives caused by changes in a single parameter. BCOU-S is a useful tool for further monitoring early DILI development.