Dang Huiping, Yan Lifeng
CAS Key Laboratory of Soft Matter Chemistry, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei, Jinzai Road 96# 230026, People's Republic of China.
Biomed Mater. 2021 Feb 3;16(2):022001. doi: 10.1088/1748-605X/abca4a.
Fluorescence imaging technology in the second near-infrared bio-channel (NIR-II) has the advantages of low light scattering and weak autofluorescence. It can obtain high spatial resolution imaging in deeper biological tissues and realize accurate diagnosis in the lesion. As a new cancer treatment method, photothermal therapy has the characteristics of obvious curative effect and small side effects. However, the hydrophobicity and non-selectivity of many fluorescent materials, aggregation-induced fluorescence quenching, and other problems lead to undesirable imaging results. Here, we reviewed the structure of the NIR-II fluorescent molecules and these dyes whose fluorescence tail emission is in the NIR-II bio-channel, discussed in detail how to realize the redshift of the dye wavelength, including modifying the push-pull electron system, extending the conjugated chain, and forming J-aggregates and other methods. We also summarize some strategies to improve brightness, including responsiveness, targeting, adjustment of aggregation mode, and aggregation-induced emission effect, thereby improving the imaging performance and therapeutic effect of NIR-II fluorescent dyes.
第二近红外生物通道（NIR-II）中的荧光成像技术具有光散射低和自发荧光弱的优点。它可以在更深的生物组织中获得高空间分辨率成像，并在病变部位实现准确诊断。作为一种新的癌症治疗方法，光热疗法具有疗效显著和副作用小的特点。然而，许多荧光材料的疏水性和非选择性、聚集诱导荧光猝灭等问题导致成像结果不理想。在此，我们综述了NIR-II荧光分子以及荧光尾发射在NIR-II生物通道中的这些染料的结构，详细讨论了如何实现染料波长的红移，包括修饰推拉电子系统、延长共轭链以及形成J-聚集体等方法。我们还总结了一些提高亮度的策略，包括响应性、靶向性、聚集模式的调整以及聚集诱导发光效应，从而提高NIR-II荧光染料的成像性能和治疗效果。
