A dibenzothiophene core-based small-molecule AIE probe for wash-free and selective staining of lipid droplets in live mammalian and fungal cells

Lipid droplets (LDs) are spherical dynamic subcellular organelles, and play crucial roles in a number of cellular functions, such as lipid metabolism, protein degradation, membrane formation, energy storage, and signal transduction. It is widely recognized that the dysfunction of LDs can lead to many diseases, and hence it is important to monitor the size, distribution, and movement of LDs in living cells. Herein, we report a dibenzothiopene core-based fluorescent probe named triphenylamine dibenzothiophene-S,S-dioxide (TPA-DBTD), which can exhibit aggregation-induced emission (AIE) characteristic and realize selective and wash-free imaging of LDs in live cells. Most importantly, this probe can efficaciously track the dynamic changes of LDs including lipophagy (an autophagic process that is responsible for the degradation of lipids) in live mammalian cells and stain LDs in fungi. Hence, we believe that TPA-DBTD with high photostability, good biocompatibility, AIE characteristic, and LD staining ability in diverse biological systems (mammalian cells and microorganisms) can find practical applications in the fields of biomedical science, cell biology, and diagnosis of LDs-associated diseases.