Seeing the unseen: AIE luminogens for super-resolution imaging

Super-resolution imaging (SRI) is of great significance to break the Abbe's diffraction limit, enabling visualization and dynamic monitoring with ultra-high resolution in both material science and biology. Fluorophores play an important role in SRI. Among them, aggregation-induced emission (ALE) luminogens (AIEgens) are one of the most promising imaging agents for SRI. They are easy to be synthesized and possess high tailoring ability, high brightness in aggregated states, large Stokes' shift, good photostability, and also excellent biocompatibility. Based on this consideration, the recent progress on AIEgens for SRI is summarized here. The working principles of AIEgens and several SRI techniques are also introduced to illustrate the material requirements. The new achievements in AIEgens research for SRI, including their chemical structures, optical properties, and applications, are highlighted in detail. The goal is to provide the readers with an overview of the recent advances in AIEgens for SRI. It is also anticipated that a deep understanding of the relationship between the AIEgens' properties and their imaging performance can be obtained. This review also aims to provide a set of guidelines to develop new AIEgens for fluorescence imaging to achieve superior resolution, thus resulting a better understanding of their mechanism in both biology and material science. (C) 2021 Elsevier B.V. All rights reserved.