Restriction of molecular motion to a higher level: Towards bright AIE dots for biomedical applications

In the late 19th century, scientists began to study the photophysical differences between chromophores in the solution and aggregate states, which breed the recognition of the prototypical processes of aggregation-caused quenching and aggregation-induced emission (AIE). In particular, the conceptual discovery of the AIE phenomenon has spawned the innovation of luminogenic materials with high emission in the aggregate state based on their unique working principle termed the restriction of intramolecular motion. As AIE luminogens have been practically fabricated into AIE dots for bioimaging, further improvement of their brightness is needed although this is technically challenging. In this review, we surveyed the recent advances in strategic molecular engineering of highly emissive AIE dots, including nanoscale crystallization and matrix-assisted rigidification. We hope that this timely summary can deepen the understanding about the root cause of the high emission of AIE dots and provide inspiration to the rational design of functional aggregates.

Automated summary

In the late 19th century, scientists discovered the phenomena of aggregation-caused quenching and aggregation-induced emission (AIE) while studying the photophysical differences between chromophores in solution and aggregate states. The concept of AIE has led to the innovation of luminogenic materials with high emission in the aggregate state based on the restriction of intramolecular motion. This review explores recent advances in molecular engineering techniques for highly emissive AIE dots, such as nanoscale crystallization and matrix-assisted rigidification, with the goal of improving their brightness and inspiring the rational design of functional aggregates.