A family of lipotropic AIEgens for high-fidelity dynamic tracking of lipid droplets in living cells

As dynamic subcellular organelles, lipid droplets (LDs) are associated with energy homeostasis and handling of cellular lipids and proteins, and their abnormal activity and quantity are involved in many serious diseases, even cancer. Thus, the biological morphology of LDs monitoring is very important to disease screening and biomedical research. In this work, we developed a series of aggregation-induced emission luminogens (AIEgens, TFI, MTFI and MOTFI) via very ordinary synthetic technology and convenient purification. Owing to large Stokes shifts (greater than 140 nm), bright red emissions, excellent photostability and good biocompatibility, these lipotropic AIEgens can specially accumulate in LDs and visually 'light up' them. In addition, the MTFI was successfully engaged to high-fidelity monitoring and tracking the LDs' movements in living cells. Moreover, the LO2 and HepG2 cells could be clearly distinguished according to the significantly different fluorescence intensity of MTFI marked LDs. Thus these AIEgens may become promising imaging molecule tools to investigate the physiological and pathology function of intracellular LDs, and show great potential for diagnosis of LDs-related diseases.