光动力疗法是近年来兴起的一种无创癌症治疗方法。光动力疗法是利用无毒性的光敏剂在特定波长光的照射下，产生活性氧杀死特定的组织，从而达到治疗效果的一种方法。然而传统光敏剂的吸收波长通常位于可见光波段，同时易受聚集诱导荧光猝灭的影响，因此限制了激发光的穿透深度以及光动力疗法的疗效。本项目旨在通过基于聚集诱导发光材料的双光子光动力疗法来克服穿透深度和聚集诱导荧光猝灭的限制，从而有效提高光动力疗法的治疗效果。在本项目中，将设计、合成具有聚集诱导发光特性、大双光子吸收截面、高活性氧产生效率、良好光稳定性和生物相容性的光敏剂。利用近红外飞秒激光激发光敏剂实现双光子光动力疗法，在细胞层面，通过杀死肿瘤细胞的效率来评估双光子光动力疗法的疗效并优化实验参数。最终利用双光子光动力疗法治疗小鼠肿瘤并进行疗效评估。该项目的研究将为扩大光动力疗法的应用提供理论和技术支持。

As an emerging cancer treatment strategy with minimal invasiveness, photodynamic therapy (PDT) is a treatment that uses a nontoxic photosensitizer (PS) in the presence of light with specific wavelength to produce reactive oxygen species (ROS), which can irreversibly destroy the targeted diseased tissue. However, the absorption wavelength of traditional PSs is usually located in the visible light band, and is also susceptible to the influence of aggregation-caused quenching (ACQ). Therefore, the penetration depth of excitation light and the effect of PDT are limited. This project aims to develop a high-performance PDT to overcome the limitation of penetrating depth and ACQ issue utilizing AIEgens based two-photon PDT. PSs with AIE effect, large two-photon absorption cross section, high ROS generation efficiency, and excellent photostability and biocompatibility will be designed and synthesized in this project. Near-infrared femtosecond laser will be used to excite PSs, enabling two-photon PDT. At the cellular level, the PDT effect will be evaluated by cancer cell ablation, which will guide the optimization of experimental parameters. Finally, the two-photon PDT will be used to the in vivo tumor therapy and subsequently its effect will be evaluated. This project will provide theoretical and technical supports for expanding PTD in medical applications.