Sun Jingzhi

Preparation and self-assembly of amphiphilic polymer with aggregation-induced emission characteristics

An amphiphilic polymer bearing tetraphenylethene (TPE) moiety was synthesized by convenient reactions. The polymer exhibits unique aggregation-induced emission (AIE) characteristics and can self-assemble to size-tunable particles in DMF/water mixtures. The polymer nanoparticles can be used for cell imaging, which provides a potential stable fluorescent tool to monitor the distribution of drugs and bioconjugates in living cells.

Application of AIE-active molecules in biosensing

Aggregation-induced emission (AIE) refers to a unique photophysical phenomenon observed for some specific fluorophores, which are faintly or non-emissive in solution but become highly emissive in solid and aggregated states. In the cases of fluorescent probes, AIE active molecules possess some unparallel advantages over their classical counterparts. On one hand, it allows more AIE active molecules to bind to the target analyte, without worrying about the aggregation-induced fluorescence quenching; thus favors fluorescence detection. On the other hand, the feature of drastic enhancement in fluorescence intensity associating with an aggregation event can be used as a method of quantitative detection. In this paper, a series of representative AIE molecules are demonstrated; their applications as biological probes in sensing of protein, DNA, G4, and chiral amines are highlighted; their working principles and features of these molecules are described. Finally, a brief outlook on the design of new AIE-active molecules and the application of AIE-molecules in relevant fields is forwarded.

Progress on heterocycle-based luminogenswith aggregation-induced emission characteristics

Aggregation-induced emission (AIE), conceptually termed by Tang et al in 2001, refers to a unique phenomenon that a series of propeller-shaped conjugated molecules are weakly or non-emissive in solution state but highly luminescent in the aggregate state. Experimental and theoretical studies have rationalized the restriction of intramolecular motion (including rotation and vibration) as the main cause for the AIE effect. Exactly opposite to conventional fluorophores that suffer from the aggregation-caused quenching (ACQ) effect, the AIE luminogens (AIEgens) could perform best in the condensed phases and enable the molecule aggregation to play positive instead of negative roles in enhancing luminescence. Attracted by this intriguing phenomenon and the application implications, scientists worldwide have actively involved in this research and promoted the development of this area. As a result, tremendous AIEgens have been synthesized and applied in optoelectronic and biologic fields etc. The progresses on the AIE have been well summarized in several excellent reviews. However, the reviewed structures of AIEgens are mostly based on the hydrocarbon ones, such as tetraphenylethene (TPE), distyrylanthracene (DSA), triphenylethene, tetraphenyl-1,4-butadiene (TPBD). Herein, we mainly review the advance of heterocycle-based AIEgens containing silicon, nitrogen, sulfur, boron and phosphorus atoms etc. for the first time. The versatile properties, such as tunable emission color, good thermal and photo-stability, and the applications of these heterocycle-based AIEgens in organic light-emitting diodes, fluorescent sensors and cell imaging etc. were also briefly discussed.