AIE active cyanostilbenes for live-cell imaging of lipid droplets

Abstract

Lipid droplets (LDs), owing to their involvement in various physiological processes and diseases such as fatty liver disease, diabetes, and cancer, have attracted considerable attention. Live cell imaging of lipid droplets allows researchers to visualize and track the movement of these organelles within living cells in real time. In this study, we synthesized trifluoromethyl-substituted cyanostilbene fluorophores containing naphthalene or julolidine groups to visualize lipid droplets in live cells and investigate the changes in the size and number of LDs upon oleic acid stimulation. The fluorophores with donor (D) and acceptor (A) substituents show strong solvatochromism due to intramolecular charge transfer (ICT). In addition, these fluorophores show enhanced aggregation-induced emission (AIE) in water, and the lipophilic trifluoromethyl substitution aids the formation of stable organogels. The morphology and size of the aggregates obtained were characterized through scanning electron microscopy and dynamic light scattering experiments. Rheology and differential scanning calorimetry were used to further characterize the organogels. Our findings suggest that these D–π–A-substituted cyanostilbenes are valuable probes for understanding live-cell LD dynamics.