Electrohydrodynamic size stratification and flow separation of giant vesicles
Original Entry by Michelle Borkin, AP225 Fall 2009
S. Lecuyer, W. D. Ristenpart, O. Vincent, and H. A. Stone, Appl. Phys. Lett., 92, 104105, 2008
electrohydrodynamics, Vesicle, suspensions
An electrohydrodynamic (EHD) method for separating small from giant unilamellar vesicles (GUVs) is presented in this paper. GUVs are fragile and common suspension separation techniques (e.g. centrifugation) are ineffective. Thus having an effective way to separate them is desirable. GUVs are of particular interest due to their ability to model biophysical systems since GUVs have similar sizes and structures (e.g. lipid bilayers, membranes) as living cells. There is also interest in using GUVs for new technology including nanoreactors and designable drug carriers. In summary, the process for separating the vesicles involves applying an oscillatory electric field which generates an EHD flow around each vesicle close to an electrode. The result is that the smaller vesicles are pulled underneath the larger ones thus lifting the larger ones off the electrode. A brief spike in the electric field is applied to keep the smaller vesicles on the bottom while a flow is applied to push the larger vesicles into a separate container. The result is the removal of >90% of the small vesicles from the GUVs.
(explain unilamellar vesicles)