Dual-Responsive Fluorescent Sensor for Monitoring ALP and SO₂ in Cholestatic Liver Injury Evaluation and Drug Screening

Cholestatic liver injury (CLI) is a pathological condition characterized by impaired bile flow and elevated levels of oxidative stress. Its clinical manifestations are often asymptomatic in the early stage, while prolonged CLI may progress to liver failure without timely intervention. However, current diagnostic and therapeutic approaches for CLI are limited in both effectiveness and availability, highlighting the critical need for reliable diagnostic modalities and innovative therapeutic agents. Given that the alkaline phosphatase (ALP) and sulfur dioxide (SO 2 ) serve as pivotal indicators in CLI pathogenesis, here we constructed a dual-responsive fluorescent sensor N–P for detecting ALP and SO 2 with dual-channel signals. This sensor has excellent water solubility, a low limit of detection (LOD = 0.5458 U/L for ALP and 0.1604 μM for SO 2 ), and a large Stokes shift (∼170 nm). Moreover, N–P enables real-time visualization of endogenous ALP and SO 2 in living cells and zebrafish. Significantly, N–P serves as a robust platform for the visual screening of potential CLI therapeutic drugs and ALP/SO 2 activators/inhibitors, as well as for the early diagnosis of CLI. This work presents a versatile fluorescent sensor for the sequential detection of ALP and SO 2, thereby contributing to the advancement in pharmaceutical development and diagnostic approaches for CLI.