Photoactive agents based on natural products have attracted substantial attention in clinical applications because of their distinct biological activity, molecular structure multiformity, and low biotoxicity. Herein, we initially modify hypocrellin B (HB) with 1,2-diamino-2-methyl propane to form near-infrared (NIR) light (>700 nm)-responsive amino-substituted HB derivative (DPAHB). The DPAHB exhibit broad absorption (400-800 nm), NIR emission (maximum emission peak at 710 nm), and high singlet oxygen (1O2) quantum yield (∼0.33) under NIR light (721 nm) irradiation. After self-assembly by using DPAHB with PEG-PLGA, the as-prepared nanovesicles (DPAHB NVs) retain efficient 1O2 generation, more interestingly, show high photothermal conversion efficiency (∼0.24) under NIR light (721 nm) irradiation for synergistic photodynamic therapy (PDT) and photothermal therapy toward hypoxic tumor. The DPAHB NVs can not only be as a fluorescence/photoacoustic imaging agent but also exhibit an even stronger PDT efficiency than that of chlorin e6 (a widely used classic photosensitizer). In vitro and in vivo studies demonstrate that DPAHB NVs possess high photothermal stability, enhanced tumor accumulation, and suitable biodegradation rate, thus, show a highly promising clinical potential as a new photoactive agent for cancer therapy.
