Dresden 2011 – scientific programme

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BP: Fachverband Biologische Physik

BP 13: Posters: Biological Membranes

BP 13.8: Poster

Monday, March 14, 2011, 17:15–20:00, P3

Confocal Raman Microscopy of Ternary Phase Domains in Model Membrane Systems — •Guillermo Beltramo, Magret Giesen, and Agnes Csiszár — Institute für Complexe Systeme Biomechanik ICS-7, Forschungszentrum Jülich, D 52425 Jülich, Germany

Recently lipid micro domains in cellular membranes as well as in model membranes like lipid bilayers and vesicles have been extensively investigated. The micro domains are formed due to a phase separation between areas of different cholesterol and lipid concentration. These membrane structures have been frequently studied using confocal fluorescence microscopy. Fluorescent dyes, however, may alter the properties of the molecules of interest. With the recent development of microscopic techniques, based on vibrational optical spectroscopy, novel means appeared to characterize lipid micro domains in model systems. Molecular vibrations are excited by non-elastically scattered photons. This is known as Raman effect: Laser light interacts with molecular vibrations in the molecule, resulting in a red-, respectively, blue-shift of the laser light. The energy shift gives detailed information on the chemical components in a membrane with high spatial and time resolution. In confocal Raman microscopy, the laser beam scans a sample volume and the membrane is imaged based on its vibrational properties. Hence, information about the membrane chemical composition is achieved bypassing the need for any staining procedures. In our work we present confocal Raman microscopy studies on model membranes composed of sphingomyeline, phospholipid, and cholesterol.