Used as a fluorescent lipid tracer in biological membranes, enabling visualization of membrane dynamics, lipid distribution, and vesicle trafficking in live and fixed cells. Its strong red fluorescence allows for high-sensitivity detection in microscopy, including confocal and fluorescence imaging. Commonly incorporated into liposomes or cell membranes to study fusion events, endocytosis, and membrane fluidity. Also employed in in vitro assays to monitor lipid-protein interactions and membrane organization due to its stable integration into bilayer structures.