AVS 61st International Symposium & Exhibition
    Biomaterial Interfaces Wednesday Sessions
       Session BI+AS-WeM

Paper BI+AS-WeM12
Second Harmonic Scattering: Characterizing the Interaction between Lipid Membranes and Water

Wednesday, November 12, 2014, 11:40 am, Room 317

Session: Nonlinear Optical & Vibrational Spectroscopy
Presenter: Cornelis Lütgebaucks, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland
Authors: C. Lütgebaucks, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland
C. Macias-Romero, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland
S. Roke, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland
Correspondent: Click to Email
Lipid membranes are essential for all organisms by separating functional compartments and mediating cellular signaling. Dioleoylphosphatidylcholine (DOPC) and Dioleoylphosphatidylserine (DOPS) are the main constituents of mammalian cell membranes. Molecular level understanding of cell membrane architecture often involves supported lipid membranes and invasive methods. We designed a second harmonic scattering (SHS) instrument that allows for investigating the molecular properties of interfaces from lipid vesicles in aqueous solution, label-free, and substrate independent. Characterizing DOPC:DOPS composed liposomes, we find that the water-lipid interaction is mainly responsible for the SHS signal. Moreover, the SHS signal increases up to a lipid mixing ratio of 9:1 and remains unchanged at lower ratios. This value coincides with the saturation value of DOPS in the outer leaflet of the mammalian membrane, when spontaneous apoptosis occurs.