Fluorogenic Detection and Characterization of Proteins by Aggregation-Induced Emission Methods

Protein is one of the four most important biomacromolecules in living systems. The detection, quantification, localization, and characterization of proteins is essential for an understanding of biological fundamentals, as well as for the diagnostics and treatment of protein-related diseases. By using intrinsic and extrinsic fluorescence, different techniques have been established to study proteins, many of which are now being routinely used in research laboratories and clinics. This review summarizes the applications of aggregation-induced emission (AIE) fluorescence in protein science. In contrast to traditional fluorescent dyes, the activation of AIE dyes is mainly attributed to the restriction of intramolecular motions. This unique turn-on mechanism of AIE dyes allows researchers to develop novel fluorogenic strategies for sensitive, selective, and reliable analysis of proteins. This review focuses on introducing AIE strategies for 1) detection, localization, and quantification of proteins; 2) probing polymer conformational transitions of proteins; 3) characterization of protein-ligand interactions; and 4) evaluation of enzyme activities. Perspectives and challenges with respect to this emerging field of protein characterization are offered.