Wash-Free β-Galactosidase-Activated Fluorescent Probe for Assessing Chemotherapy Efficacy in Ovarian Cancer Organoids

Reliable evaluation of chemotherapy efficacy is essential for optimizing treatment strategies in ovarian cancer. Organoids provide a physiologically relevant model to capture tumor heterogeneity, yet practical tools for functional assessment remain limited. Here, we report a wash-free near-infrared β-galactosidase-activated fluorescent probe Hcy-SO₃-β-Gal for noninvasive imaging of ovarian cancer organoids. The probe remains quenched in its native form and is rapidly activated upon enzymatic cleavage by β-galactosidase, an enzyme associated with therapy-induced senescence and stress responses in cancer cells. The wash-free property enables real-time imaging with minimal background interference, facilitating dynamic monitoring of cellular responses to chemotherapy. Applied to organoid cultures, the probe provided sensitive readouts that correlated strongly with standard viability assays, while offering advantages of operational simplicity and high-throughput compatibility. This work introduces a practical imaging platform that integrates molecular specificity with translational potential, supporting precision evaluation of chemotherapy efficacy and informing personalized therapeutic strategies.