Brillouin light scattering measurement of the elastic properties of aligned multilamella lipid samples.

Brillouin measurements of the elastic properties are presented for aligned multilamella samples of both pure dipalmitoyl phosphatidylcholine at various temperatures and water concentrations and for the same compound containing 33 mol% cholesterol at various temperatures and two water concentrations. For pure dipalmitoyl phosphatidylcholine the elastic moduli change significantly at the gel transition and the modulus for area compression of individual bilayers is inferred to be an order of magnitude larger below the gel transformation than above. The presence of cholesterol is shown to influence the elastic behavior of dipalmitoyl phosphatidylcholine.