Regensburg 2010 – scientific programme
Parts | Days | Selection | Search | Downloads | Help
CPP: Fachverband Chemische Physik und Polymerphysik
CPP 26: Micro and Nanofluidics I
CPP 26.13: Talk
Wednesday, March 24, 2010, 17:15–17:30, H39
Dynamics of lipid bilayer formation using water in oil emulsions 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
Using lipid stabilized water-in-oil emulsions, we investigate the process of formation of lipid bilayers between emulsion droplets. For sufficiently high lipid concentrations in the oil phase, the oil-water interface is fully covered by a monolayer of lipid molecules. When two such monolayers are brought together, the oil separating them drains away, thus forming a lipid bilayer. We use a combination of high speed microscopy and electrical measurements to follow the dynamics of oil drainage and the subsequent bilayer formation. We find two typical modes of membrane formation depending on the surfactant concentration: (i) for lower concentrations, a zipper like mechanism where an oil lens rapidly leaves the region between the two lipid monolayers and (ii) at higher concentration the membrane forms as the droplets tend to separate from each other, similar to a decompression effect. In the first case, we find that the oil drainage reaches a typical velocity of 2mm/s, also corroborated by the rise time of the electrical capacitance due to the bilayer. In the latter case, we report on the critical length and time scales of the membrane formation and also the effect of surfactant concentration on the stability of the bilayer formation by decompression.