基于双发射AIE染料的比率型分子/纳米荧光探针研究

Ratiometric fluorescent probes using conventional rigid-planar organic dyes as fluorophores typically suffer from the aggregation-caused quenching (ACQ) defect that severely hamper their application. Substituting traditional fluorescent dyes with novel aggregation-induced emission (AIE) dyes to develop ratiometric AIE fluorescent probes is an effective way to fundamentally solve the ACQ problem. To promote the development of ratiometric AIE fluorescent probes, the dual-emission AIE fluorescent dye and the efficient design mechanism are key factors. In this project, a series of new fluorescent dyes with the characteristics of dual-emission and AIE will be designed and synthesized based on the nature of "monomer-excimer-multimer" morphology distribution of cyanovinyl pyrene-derivatives. By using the obtained dyes as fluorophores or precursors, two ratiometric AIE molecular/Nano fluorescent probes for the example analytes of β-galactosidase and hyaluronidase will be prepared based on the mechanism of change in fluorescent dye solubility after reaction with analytes. Dual-channel fluorescence detection of the example analytes in living cells will be performed. The feasibility of the design for dual-emission AIE fluorescent dyes and the responsive mechanism of ratiometric AIE fluorescent probes to analytes will be evaluated. Our work will greatly facilitate the development of dual-emission AIE fluorescent dyes and the design mechanism of ratiometric AIE fluorescent probes, thus providing a new solution for ACQ.

由于以刚性平面结构的传统荧光染料作为发光基团，比率型荧光探针普遍存在聚集导致猝灭（ACQ）效应，严重制约了其实际应用。利用聚集诱导发光（AIE）荧光染料替代传统荧光染料，发展比率型AIE荧光探针，将从根本上克服ACQ缺陷，而双发射AIE荧光染料的开发与高效设计机制的发掘是推动比率型AIE荧光探针发展的重要因素。本项目拟利用氰乙烯基芘衍生物的“分子态-二聚态-多聚态”形态分布特性发展一系列既具有双波长发射、又具有AIE性质的新型荧光染料，并以其为发光基团或前体，利用与目标物作用后荧光染料溶解性变化的机制，制备β-半乳糖苷酶和透明质酸酶两种示例目标物的比率型分子/纳米荧光探针，开展细胞内双通道荧光成像分析。本研究将评价荧光染料分子设计与荧光探针机制设计的可行性，为比率型AIE荧光探针的开发提供荧光染料和设计机制的支持，为ACQ问题提供全新的解决方案。

聚集诱导发光（AIE）染料能够有效克服常规染料的聚集荧光猝灭（ACQ）缺陷，在荧光探针设计中展现出显著优势。然而，由于缺少有效设计机制，具有双发射性质的AIE染料鲜见于报道。比率型荧光探针由于自校正功能比增强型荧光探针具有更高的定量准确度。本项目围绕双发射AIE染料和比率型分子探针的设计与应用及相关辅助性工作的研究，以芘、氟硼二吡咯、四苯乙烯、氰乙烯、苯并唑、吡啶等基团为构建单元设计并合成了10多种荧光染料，考查了其光物理性质，重点发觉了双发射AIE染料及结构新颖的AIE或双发射染料，探究其双发射和AIE性质的内在机制。基于“单体-二聚体-多聚体”、“单体-激发态二聚体”或“单体-多聚体”的分子状态转变机制，通过考查所设计染料对相关目标物的光谱响应性或在染料分子上修饰功能化识别能团，构建了生物活性分子（肝素、过氧化亚硝酰等）和生理微环境（粘度、pH等）的比率型或增强型荧光探针，系统考查了探针的分析性能，探究了其光谱响应机制，并将其应用于细胞内相关目标物的双通道或单通道荧光成像分析。研究结果初步证实了“单体-二聚体-多聚体”分子状态转变机制在设计双发射AIE荧光染料的可行性，为AIE染料和比率型荧光探针的发展起到了一定的推动作用。依托本项目，发表学术论文7篇，申请专利2项，培养研究生6人。