A sensitive bio-probe for tracking lipid droplets with large Stokes shift and its application in cell imaging

Lipid droplets (LDs) including triacylglycerols and cholesteryl esters are applied for protein transformation and protein maturation in living bodies, which have an important effect on lipid metabolism, homeostasis, and interactions with other organelles. The imbalance of LDs could lead to many serious diseases including insulin resistance, cancer, obesity, liver disease, cardiovascular disease, and neurodegenerative disease. The diameter distribution of LDs is quite extensive from 100 nm to 100 µm. Herein, we designed and constructed a novel organic bio-probe TzAr-N for LDs cell imaging with much more hydrophobic and viscous environment compared to cytosol by using 1,3,5-triazine as electron acceptor. This sensitive probe exhibited favorable merits including large Stokes shift (almost 80 nm), good LDs targeting ability, and a low biological toxicity, which also could not be affected by wide range of pH values. Furthermore, the bio-probe TzAr-N could also mark LDs distribution in living HeLa cells.