Fluorescence lifetime imaging has been a powerful tool for biomedical research. Recently, fluorescence lifetime-based multiplexing imaging has expanded imaging channels by using probes that harbor the same spectral channels and distinct excited state lifetime. While it is desirable to control the excited state lifetime of any given fluorescent probes, the rational control of fluorescence lifetimes remains a challenge. Herein, we chose boron dipyrromethene (BODIPY) as a model system and provided chemical strategies to regulate the fluorescence lifetime of its derivatives with varying spectral features. We find electronegativity of structural substituents at the 8’ and 5’ positions are important to control the lifetime for the green-emitting and red-emitting BODIPY scaffolds. Mechanistically, such influences are exerted via the photo-induced electron transfer and the intramolecular charge transfer processes for the 8’ and 5’ positions of BODIPY, respectively. Based on these principles, we have generated a group of BODIPY probes that enable imaging experiments to separate multiple targets using fluorescence lifetime as a signal. In addition to BODIPY, we envision modulation of electronegativity of chemical substituents could serve as a feasible strategy to achieve rational control of fluorescence lifetime for a variety of small molecule fluorophores.

中文翻译：

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多重成像荧光寿命的化学控制

荧光寿命成像已成为生物医学研究的强大工具。最近，基于荧光寿命的多重成像通过使用具有相同光谱通道和不同激发态寿命的探针扩展了成像通道。虽然希望控制任何给定荧光探针的激发态寿命，但荧光寿命的合理控制仍然是一个挑战。在这里，我们选择二吡咯亚甲基硼（BODIPY）作为模型系统，并提供化学策略来调节具有不同光谱特征的其衍生物的荧光寿命。我们发现 8' 和 5' 位结构取代基的电负性对于控制发绿光和发红光​​ BODIPY 支架的寿命很重要。从机理上讲，这种影响分别是通过 BODIPY 8' 和 5' 位的光诱导电子转移和分子内电荷转移过程产生的。基于这些原理，我们生成了一组 BODIPY 探针，使成像实验能够使用荧光寿命作为信号来分离多个目标。除了 BODIPY 之外，我们预计化学取代基电负性的调节可以作为实现各种小分子荧光团荧光寿命合理控制的可行策略。