End Group Nonplanarization Enhances Phototherapy Efficacy of A–D–A Fused-Ring Photosensitizer for Tumor Phototherapy
Bing Lü, Hui Quan, Zhecheng Zhang, Tengfei Li, Jin Wang, Yue Ding, Yang Wang, Xiaowei Zhan, Yong Yao
Abstract
Enhancing the phototherapy efficacy of organic photosensitizers through molecular design is a fascinating but challenging task. Herein, we propose a simple design strategy to first realize the generation of superoxide anion radical (O 2 •– ) by A–D–A fused-ring photosensitizers. Through replacing one cyano group of traditional end group with an ester group, we designed a novel nonplanar end group (A unit) to synthesize a novel A–D–A photosensitizer F8CA. In a comparison with its counterpart F8CN with the traditional end group, F8CA displays more loose packing and larger spin–orbit coupling constants. The F8CA nanoparticles showed higher photodynamic activities with the generation capability of singlet oxygen ( 1 O 2 ), hydroxyl radical ( • OH), and O 2 •–, while F8CN nanoparticles could only generate 1 O 2 and • OH. In addition, F8CA nanoparticles still remain high photothermal conversion efficiency (61%). As a result, F8CA nanoparticles perform well in hypoxia-tolerant tumor phototherapy. This study brings an effective design thought for A–D–A photosensitizers.