Emerging designs of aggregation-induced emission luminogens for lipid droplets imaging

Lipid droplets (LDs) are organelles that have evolved to store intracellular neutral lipids and maintain cellular energy homeostasis. Once considered as inert fat particles, they have recently gained much attention. Along with the rapid development of research, LDs are captivating increasingly concern since being established to be dynamic and mobile, which is closely linked to metabolic disorders and diseases such as obesity, diabetes and cancer. Therefore, the development of reliable imaging tools that enable specific recognition and in-depth study of LDs is of great significance. Traditional dyes used for LDs fluorescence imaging may suffer from drawbacks of low signal-to-noise ratio, self-decomposition and aggregation-caused quenching phenomena, which severely hinder further studies and advances. In recent years, LDs targetable probes with aggregation-induced emission (AIE) property have arouse considerable interests because they offer an alternative solution for overcoming the aforementioned deficiencies. Typically, AIE fluorescence probes share multitude advantages in terms of excellent brightness as aggregates, large Stocks shifts, good photo-stability and high signal-to-noise ratio. In this review, the importance of LDs is introduced, and then the research progress of representative AIE fluorescence probes for LDs imaging and biological applications at cell, tissue and in vivo levels are separately discussed.