Interrogating amyloid aggregation with aggregation-induced emission fluorescence probes

To date, approximately 50 proteins have been identified that can misfold and aggregate to form amyloid fibrils and cause neurodegenerative diseases such as Alzheimer disease, Parkinson disease and Huntington disease. The formation of the amyloid fibrils from the precursor proteins and how pre-fibrils and fibrils formation relate to disease have remained elusive. To assist our understanding of the amyloid fibrils, many molecular fluorescence probes, such as thioflavin-T, have been developed to help investigating area including pre-fibrils and fibrils detection, structures of amyloid aggregates, the staining of amyloid in vitro, ex vivo and in vivo. In this mini-review, we focus on amyloid studies involving the use of aggregation-induced emission (AIE) fluorescence probes that are non-emissive when molecularly dissolved but can be induced to emit intensely upon aggregation. The AIE property overcomes the disadvantage of the traditional fluorescence probes with aggregation-caused quenching effect. The design, properties, and application of AIE fluorescence probes on the amyloid fibril's detection, amyloid fibril's structure, and formation dynamics study, and use in investigating potential therapeutic interventions are discussed in this mini review.