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BP: Fachverband Biologische Physik
BP 7: Poster I
BP 7.1: Poster
Monday, March 23, 2009, 17:45–20:00, P3
Self Assembled Asymmetric Lipid Bilayers in Microfluidic Channels — •Shashi Thutupalli1, Ralf Seemann1,2, and Stephan Herminghaus1 — 1Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany — 2Experimental Physics, Saarland University, Saarbrücken, Germany
Biological lipid membranes are predominantly asymmetric. In the plasma membranes of eukaryotic cells, for example, there is an abundance of phosphatidylcholine and sphingomyelin in the outer leaflet while aminophospholipids are primarily in the cytosolic leaflet. The biological importance of asymmetric lipid bilayers has motivated many studies using model systems, such as planar bilayers, supported bilayers, and vesicles. However, there are numerous experimental difficulties regarding such model asymmetric bilayer systems, in particular studying membrane proteins and ion channels. Here we report a highly robust method to simultaneously form many asymmetric bilayers using gel emulsions generated in a microfluidic channel. Liposomes included inside a droplet of water in an external phase of oil reach the oil-water interface to form a lipid monolayer. Such droplets, comprising different lipid monolayers, are brought together to form asymmetric lipid bilayers at the droplet interfaces. Significant advantages in our system are the monodispersity of the membranes thus formed and the ability to simultaneously form symmetric and asymmetric membranes bounding the same droplet. Further, we present electrical characterization of these membranes and demonstrate ion conduction via the incorporation of the ion channel Gramicidin A into these membranes.