Hypoxia‐Responsive Photosensitizer Targeting Dual Organelles for Photodynamic Therapy of Tumors

Abstract Developing safe and precise image‐guided photodynamic therapy is a challenge. In this study, the hypoxic properties of solid tumors are exploited to construct a hypoxia‐responsive photosensitizer, TPA‐Azo . Introducing the azo group into the photosensitizer TPA‐BN with aggregation‐induced emission quenches its fluorescence. When the nonfluorescent TPA‐Azo enters hypoxic tumors, it is reduced by the overexpressed azoreductase to generate a fluorescent photosensitizer TPA‐BN with an amino group that exhibits fluorescence‐activatable image‐guided photodynamic therapy with dual‐organelle (lipid droplets and lysosomes) targeting. This design strategy provides a basis for the development of fluorescence‐activatable photosensitizers.