Interactive Aggregation-Induced Emission Systems Controlled by Dynamic Covalent Chemistry.

Aggregation-induced emission (AIE) molecules show all kinds of application in biological research, chemical sensing, and medical study. However, most of the reported molecules are based on the performance of the single molecular entity. In this paper, a molecular system for real-time sensing through combination of dynamic covalent chemistry and aggregation-induced emission was rationally designed and tested. The aggregated particles exhibit different fluorescence emission colors upon the addition of various kinds of chemical reagents. The LC-MS analysis reveals that the breakage, formation, and exchange of the disulfide bonds in the molecular system occur spontaneously upon different reagents (base/acid and cysteine), which leads to a change in the proportion of different components in the system accordingly. Meanwhile, the fluorescence emission of the AIE system exhibits blue/red shift accompanied by intensity changes. Moreover, the particle size of the aggregated molecules gradually increased with the change of the chemical environment, which could be the result of the nucleus growing through intermolecular hydrogen bonding among molecular components. Thus, the chemical environment change results in the interactions of molecules, which further leads to the variation of dynamic fluorescence emission and morphology. The result represents a promising future for a dynamic AIE molecular system in the bioimaging and sensing study.