Application of AIE-active probes in fluorescence sensing

熒光傳感作為化學傳感領域中的一項重大技術,具有靈敏度高、選擇性好和響應快等優點,但是傳統有機發光分子在高濃度或者聚集狀態下,容易發生熒光強度的降低或是完全消失,這在一定程度上不利于其在應用中發揮最佳效果.聚集誘導發光（AIE）概念的提出為解決聚集導致發光猝滅（ACQ）的難題提供了方案,實現了發光分子在聚集態下的高熒光量子產率.具有AIE特性的發光分子被用作熒光傳感器不僅具有高亮度的熒光信號,而且不必擔心由于分子聚集導致的熒光信號的降低或猝滅.同時,由于某些分子聚集程度的增強導致的熒光顏色和強度的變化,可以被用來實現對靶標物的定性和定量分析.本文簡述了近幾年來AIE分子在熒光傳感方面的應用,如離子檢測、氣體、有機小分子、爆炸物、蛋白質及酶等化學/生物傳感器,同時對基于AIE分子的熒光傳感器在設計和應用前景做了展望. Fluorescent probes that exhibit distinct advantages of high sensitivity, good selectivity, fast response speed, etc., have been widely applied in diverse sensing areas. However, the fluorescence of traditional organic probes tends to decrease or be quenched at high concentration or in aggregate state due to the aggregation-caused quenching (ACQ) effect, which limits their application in sensing areas. In 2001, our group coined the concept of aggregation-induced luminescence (AIE), which is exactly opposite to the ACQ effect and refers to a unique phenomenon that a kind of non- or weakly emissive luminogens in dilute solutions are induced to emit intensely upon aggregation or in solid state. Thus, the AIE-active luminogens (AIEgens) provide an alternative to solve this difficulty. Thanks to their intrinsic advantages, the fluorescent sensors based on AIEgens show lower background, higher signal-to-noise ratio and more outstanding resistance to photobleaching etc. Moroever, the AIE probes not only could overcome the problem encountered by ACQ ones, but also achieve faster and more sensitive detection of the targets. Thus, using AIE probes to detect a wide varity of targets is one of the hot research areas. To highlight the progress in this area, herein, we briefly summarize the sensing applications of AIEgens. First, we introduced the AIE probes used in the detection of ions, including K+, Hg2+, Fe3+, CN-, ClO-, PO43-, etc. Notably, the fluorescent probes based on AIEgen could realize the selective detection of various ions not only in the organic solutions, but also in aqueous solutions. Next, we discussed the detection of low mass molecules using AIE probes for they play a very important role in life activities and their content can reflect the health status and life information of an organism. The used low mass molecules include gas (NH3, CO2, H2S), explosive (PA, TNT), biothiol (Gys, GSH), and ATP and so on. Third, we summarized the qualitative and quantitative sensing of biomacromolecules, such as DNA, proteins, enzyme, by AIE probes, which is critical to the life sciences, biotechnology, and pharmaceutical industries. Fourth, the application of AIE probes in the fields like pH response, cell membrane imaging, mitochondrial imaging and fungal detection are reviewed. Finally, the prospects for the design and application of AIE probes are presented. We hope that this review will stimulate interests in AIE-based sensors and provide some new ideas for researchers working in this area. © 2020, Science Press. All right reserved.