A benzopyran-based near-infrared fluorescent probe with a large stokes shift for visualizing cysteine dynamics in hepatic ischemia-reperfusion injury and tumor tissues.

Cysteine (Cys) is a key biomarker of oxidative stress and is closely associated with pathologies such as hepatic ischemia-reperfusion injury (HIRI) and cancer. However, existing fluorescent probes for Cys detection often lack practicality in complex disease models. Herein, we developed a near-infrared fluorescent probe, Cys398, with a large Stokes shift, for high-fidelity in vivo imaging of Cys. The probe demonstrated high sensitivity, selectivity, and anti-interference capability, enabling real-time visualization of both exogenous and endogenous Cys in live cells and mice. In HIRI models, it revealed a dynamic increase in Cys during ischemia and a decrease upon reperfusion. Additionally, it detected elevated Cys levels in colorectal tumors compared to normal tissues. This study provides the first dedicated imaging tool for Cys dynamics in HIRI and validates its utility in tumor models, offering a valuable platform for studying oxidative stress-related diseases.