Cholesteryl esters consist of a fatty acid esterified to the 3β-hydroxyl group of cholesterol. These very nonpolar species are the predominant lipid components of atherosclerosis plaque and low- and high-density lipoporotein (LDL and HDL) cores. The green fluorescent BODIPY™ FL C₁₂ cholesteryl ester can be used as a tracer of cholesterol transport and receptor-mediated endocytosis of lipoproteins by fluorescence microscopy and as a general nonexchangeable membrane marker.