氧自由基型酞菁锌光敏剂的激发态释能机制 及光动力治疗研究

Photodynamic therapy is a clinically approved novel therapeutic technique that employs photosensitizer in the presence of suitable light to produce a cytotoxic reactive oxygen species (ROS). According to the ROS types, photosensitizers are divided into Type I (free radical) and Type II (singlet oxygen). Compared with Type II, Type I has low dependence on oxygen, presenting excellent prospects in overcoming the limitations of the hypoxic cancer treatment. However, there is a limited scope of Type I photosensitizers. Moreover, few studies concentrated on the mechanism research, which hinders the development of Type I photodynamic therapy. This study proved that zinc phthalocyanate (ZnPc) has a negligible singlet-triplet energy gap, ultrafast intersystem crossing rate (3.8× 10⁶s^-1), and a long triplet excited state lifetime (327 ns), all of these together give rise to facile triplet-photosensitization. Furthermore, ZnPc exhibits efficient generation of superoxide anion radicals and hydroxyl radicals but negligible singlet oxygen production, validating its Type I feature. Finally, we demonstrated the preliminary in vitro photodynamic therapy mediated by ZnPc.