SYNTHETIC ASYMMETRIC VESICLES BUILT USING MICROFLUIDIC TECHNOLOGY AT HIGH-THROUGHPUT

We report on a novel microfluidic strategy for building monodisperse asymmetric vesicles with customized composition, size, and interfacial properties at high-throughput. The microfluidic device encompasses a triangular post region and two flow-focusing regions. The major steps involved in the vesicle building process include: (1) forming highly uniform water emulsion templates in the inner-leaflet lipid solution, (2) replacing the inner-leaflet lipid solution with the outer-leaflet lipid solution, (3) creating water-in-oil-in-water double emulsions, and (4) extracting the excess outer-leaflet lipid solution from the double emulsions. Bilayer membrane asymmetry and unilamellarity are confirmed using a fluorescence quenching assay and quantitative measurements of fluorescent intensities. This method addresses many of the deficiencies found in existing technologies, and yields asymmetries as high as 95%. The asymmetric vesicles built using this strategy hold the potential to serve as model systems to investigate fundamental problems in membrane biology.