Three Birds with One Stone: Acceptor Engineering of Hemicyanine Dye with NIR‐II Emission for Synergistic Photodynamic and Photothermal Anticancer Therapy
Wenwen Cao, Yu Zhu, Fapu Wu, Yang Tian, Zhaoming Chen, Weijia Xu, Senyao Liu, Tingting Liu, Hu Xiong
Abstract
Abstract It is challenging to develop a near‐infrared (NIR) small molecular photosensitizer for synergistic phototherapy in deep tissues. Herein, first, a heavy‐atom‐free NIR hemicyanine photosensitizer (BHcy) for 808 nm light‐mediated synergistic photodynamic therapy/photothermal therapy (PDT/PTT) anticancer therapy by leveraging the acceptor engineering strategy is reported. This strategy endows BHcy with a more planar and larger π‐conjugated structure, resulting in long NIR absorption/emission at 770/915–1200 nm as well as enhanced singlet oxygen ( 1 O 2 ) generation ability and photothermal effect, which is ascribed to the reduced energy levels of excited singlet/triplet states and the promoted intersystem crossing process. Notably, BHcy‐based nanoparticles (BHcy‐NPs) exhibit efficient 1 O 2 yield (12.9%) and high photothermal conversion efficiency (55.1%). More importantly, BHcy‐NPs are able to significantly kill cancer cells by destroying main organelles and inhibit tumor growth in vivo after a single irradiation. Overall, this study provides a strategy to design new heavy‐atom‐free PDT/PTT agents for potential clinical applications.