A near-infrared AIE probe for super-resolution imaging and nuclear lipid droplet dynamic study

In contrast to the lipid droplets (LDs) in the cytoplasm, nuclear lipid droplets (nLDs), generated from the metabolically active inner nuclear membrane, contribute to the nuclear lipid homeostasis, locally regulate the availability of signaling lipids, and exchange the proteins between LDs and nuclei. Since the currently available fluorescence tools for imaging and tracking nLDs are limited, exploring a new nLD probe would be highly beneficial for studying the biogenesis and functional significance of nLDs. Herein, we developed a near-infrared probe, namely DTZ-TPA-DCN, which possessed the aggregation-induced emission (AIE) property with good biocompatibility for cytoplasm LD and nLD imaging. DTZ-TPA-DCN could be used for the super-resolution imaging of LDs with the structured illumination microscopy. By labelling nLDs, we could monitor the nLD formation under an ER stress, and for the first time, we observed that the signaling lipid, namely diacylglycerol (DAG), enhanced the formation of the nLDs. Together, DTZ-TPA-DCN provided a promising imaging tool for nLD studies, which contributed to a better understanding of the physiological significance of nLDs.