AIE Bioconjugates for Biomedical Applications

Fluorescence-based techniques have found potential biomedical applications owing to their high sensitivity, rapid response, and in situ characteristics. Traditional fluorescent probes suffer from aggregation-caused quenching effects, which limit their usage at high concentrations or in nanoparticles. Aggregation-induced emission (AIE), on the other hand, is a phenomenon wherein luminogens are non-emissive in dilute solutions but highly emissive in the aggregate and solid states. AIE bioconjugates formed by covalent linkage of AIE luminogens to biomolecules are especially promising candidates for biomedical applications because they show excellent biocompatibility, good water solubility, high specificity to the target of interest, wide functionality, and smart responsiveness. This review summarizes the methodologies in synthesizing AIE bioconjugates and their intricate applications in biosensing, bioimaging, image-guided therapy, and "Lab-in-cell" over the past 20 years. Perspectives are also shared to inspire enthusiasm and motivate researchers to further develop this emerging field.