Tracking lipid droplet dynamics for the discrimination of cancer cells by a solvatochromic fluorescent probe

High lipid metabolism is one of the fundamental characteristics of cancer cells different from normal cells due to lots of energy needed for the fast proliferation of cancer cells. As an important organelle to supply cellular energy, however, the difference of lipid droplets (LDs) in their dynamic features between cancer cells and normal cells remains unclear. A key difficulty is to develop a specific fluorescence-tunable probe with high signal-to-noise for rapidly and accurately identifying cancer cells via tracking lipid droplets’ dynamics. Here, we report a solvatochromic fluorescent probe, dansyl-morpholine (DNS-M), with high LDs-specificity to achieve the effective discrimination of cancer cells from normal cells by visually profiling the feature difference of LDs dynamics. Probe DNS-M is synthesized easily by one-step reaction, and possesses a large Stokes shift ∼200 nm, excellent photostablity and LDs-targeted capability with high overlap coefficient up to 0.97. Due to the remarkable biomembrance penetration, LDs-specificity and photostability, DNS-M has been applied to distinguish cancer cells from normal cells rapidly within 1 min in living cells and fixed cells, and real-time track dynamic behaviors of LDs in cancer cells, such as association, dissociation and fusion. More importantly, a significant difference in LDs behavior modes between cancer cells and normal cells is successfully visualized for the first time with our probe. We envision that our probe will become a rapid and easy-to-operate tool for cancer diagnosis and deeper understanding of LDs-related behaviors in cancer cells.