Reengineering of Donor–Acceptor–Donor Structured Near-Infrared II Aggregation-Induced Emission Luminogens for Starving-Photothermal Antitumor and Inhibition of Lung Metastasis
Mingwang Yang, Suyin Wang, Xinwen Ou, Junjun Ni, S. Segawa, Jianwei Sun, Feng Xu, Ryan T. K. Kwok, Jing Zhao, Jacky W. Y. Lam, Guorui Jin, Ben Zhong Tang
Abstract
Electron acceptor possessing strong electron-withdrawing ability and exceptional stability is crucial for developing donor–acceptor–donor (D-A-D) structured aggregation-induced emission luminogens (AIEgens) with second near-infrared (NIR-II) emission. Although 6,7-diphenyl-[1,2,5] thiadiazolo [3,4- g ] quinoxaline (PTQ) and benzobisthiadiazole (BBT) are widely employed as NIR-II building blocks, they still suffer from limited electron-withdrawing capacity or inadequate chemo-stability under alkaline conditions. Herein, a boron difluoride formazanate (BFF) acceptor is utilized to construct NIR-II AIEgen, which exhibits a better overall performance in terms of NIR-II emission and chemo-stability compared to the PTQ- and BBT-derived fluorophores. With finely tuned intramolecular motions and strong D–A interaction strength, TPE-BFF simultaneously exhibits high molar extinction coefficient ( ε= 4.31 × 10 4 M –1 cm –1 ), strong NIR-II emission (Φ = 0.49%) and photothermal effect (η = 58.5%), as well as high stability. Thanks to these merits, the thermosensitive nanoparticles constructed by integrating TPE-BFF and the antiglycolytic agent 2-deoxy- d -glucose (2DG) are successfully utilized for imaging-guided photothermal antitumor lung metastasis by regulating glycolysis and reducing ATP-dependent heat shock proteins. Combining experimental results and theoretical calculations, BFF proves to be an outstanding electron acceptor for the design of versatile NIR-II AIEgens. Overall, this study offers a promising alternative for developing multifunctional NIR-II AIEgens in biomedical applications.