Molecular Engineering of membrane structure targeted photosensitizers for antitumor photodynamic therapy

Photodynamic therapy (PDT) has been used to cure special diseases or the diseases that localized at special sites in comparison with conventional therapy, due to its high spatiotemporal selectivity, non-invasion, low drug resistance. However, vast majority of photosensitizers (PSs) still suffer from several limitations including poor aqueous solubility and poor photostability. Here, we used two strategies, promoting the intramolecular charge transfer and terminal modification, to overcome these limitations and enhance therapeutic effects. Three membrane-structure targeted molecules, 3CN-Np, 3CN–OH, and 3CN-QA, were designed and synthesized, which exhibited high extinction coefficient, excellent photostability and reactive oxygen species (ROS) productive capacity. In cell imaging, the designing molecules would stain endoplasmic reticulum for 3CN-Np and 3CN–OH, and cell membrane for 3CN-QA, respectively. Afterwards, we used white light (25 mW/cm²) to irradiate the probe cultured cells for 20 min, the ratio of the dead and live cells was 3.0 for 3CN-Np, 3.5 for 3CN–OH, and 3.7 for 3CN-QA. Based on the high cell apoptosis in vitro under a white-light, 3CN–OH was selected to inhibited tumor growth in vivo, and the tumor volume was reduced to 45 % with non-toxicity to vitals. The study provided new sights in developing PSs with high water-solubility, photostability, and ROS generating ability in white-light mediating PDT system.