Xu Yan, Yang Weitao, Yao Defan, Bian Kexin, Zeng Weiwei, Liu Kai, Wang Dengbin, Zhang Bingbo
Department of Medical Ultrasound , Shanghai Tenth People's Hospital , Tongji University Cancer Center , Tongji University School of Medicine , Shanghai 200072 , China . Email:
Department of Radiology , Xinhua Hospital , Shanghai Jiao Tong University School of Medicine , Shanghai 200092 , China.
Chem Sci. 2019 Nov 11;11(2):419-428. doi: 10.1039/c9sc04901k. eCollection 2020 Jan 14.
Semiconducting polymer (SP)-based afterglow luminogens are showing increasing potential for imaging because of their long-life luminescence and the associated benefits (, zero-autofluorescence background and high signal-to-noise ratio). However, such organic afterglow luminescence agents are still rare and their application is usually limited by their relatively low afterglow intensity and short afterglow duration. Herein, we report an aggregation-induced emission (AIE) dye-powered SP afterglow luminogen by leveraging on the unique characteristics of an AIE dye to circumvent the concentration-quenching effect, enhance afterglow intensity and prolong afterglow duration. The underlying working mechanism is investigated by a series of experiments and it is found that the AIE dye provides sufficient O to excite SPs and form massive amounts of high-energy intermediates, and then the SP intermediates emit photons that can activate the AIE dye to generate O and simultaneously trigger the energy transfer process between the SPs and AIE dye, resulting in a deep-red emission. It is this closed-loop of "photon-O-SP intermediates-photon" that provides the afterglow emission even after the cessation of the excitation light. The as-prepared luminogen shows good performance in tumour imaging. This study demonstrates the advantages of AIE-facilitated afterglow luminescence and discloses its mechanism, and hopefully it could inspire the development of other innovative designs for cancer theranostics.
基于半导体聚合物（SP）的余辉发光体因其长寿命发光及相关优势（零自发荧光背景和高信噪比）在成像方面展现出越来越大的潜力。然而，这类有机余辉发光剂仍然稀少，其应用通常受到相对较低的余辉强度和较短的余辉持续时间的限制。在此，我们通过利用聚集诱导发光（AIE）染料的独特特性，报道了一种由AIE染料驱动的SP余辉发光体，以规避浓度猝灭效应、增强余辉强度并延长余辉持续时间。通过一系列实验研究了其潜在的工作机制，发现AIE染料提供足够的氧来激发SP并形成大量高能中间体，然后SP中间体发射光子，这些光子可激活AIE染料以产生氧并同时触发SP与AIE染料之间的能量转移过程，从而产生深红色发射。正是这种“光子 - 氧 - SP中间体 - 光子”的闭环即使在激发光停止后仍能提供余辉发射。所制备的发光体在肿瘤成像中表现出良好的性能。本研究展示了AIE促进的余辉发光的优势并揭示了其机制，有望激发癌症诊疗其他创新设计的发展。
