Rational Design of a Dual-Locked Fluorescent Probe for Precise Imaging of Tumor via β-Galactosidase/Viscosity Activation

Fluorescence imaging is widely applied in oncology owing to its cost-effectiveness, noninvasiveness, and real-time imaging capability. Many activatable fluorescent probes targeting tumor biomarkers, such as β-galactosidase (β-gal) and viscosity, have been developed. However, the reliance on a single-response mechanism limits their ability to capture the dynamic alterations within tumors during cancer progression and chemotherapy. In this study, we rationally designed and developed ZW-gal, a dual-locked near-infrared (NIR) probe activated by both β-gal activity and viscosity. ZW-gal exhibited favorable photophysical properties, such as a large Stokes shift (125 nm), rapid enzymatic activation (within 2 min), and a strong viscosity-dependent fluorescence enhancement (up to 24.6-fold). Leveraging this dual-responsiveness, ZW-gal successfully distinguished cancer from normal cells, visualized doxorubicin-induced cancer cell senescence, and monitored cell death. In a mouse model of liver cancer, ZW-gal enabled precise tumor localization and identified senescent tumors. Moreover, through in situ spraying, ZW-gal provided real-time surgical navigation, facilitating complete tumor resection. Building on these advantages, ZW-gal represents a powerful tool with broad potential to advance both basic cancer research and personalized clinical applications.