Quantitative spontaneous Raman scattering spectroscopy in artificial binary lipid membranes

The cholesterol concentration in lipid membranes is an important parameter that influences signaling processes as well as the structure of membranes. We show that the cholesterol content in giant unilamellar vesicles from binary lipid mixtures of cholesterol and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine can be quantitatively assessed with spontaneous Raman scattering spectroscopy. An analytical model employing correlation analysis is introduced, which can be applied for the determination of the actual cholesterol content in unilamellar lipid membranes of lipid compositions that are unknown or, because of external effects, deviant from the weighed-in values.