Single-step microfluidic generation of cell-sized giant unilamellar vesicles: Characterization and dielectrophoretic patterning and sorting

Abstract: Giant Unilamellar Vesicles (GUV) have the potential to play a dominating role in future scientific efforts to understand and model biological systems through the creation of artificial cells. GUV:s span a wide range of possible applications that include their use as biosensors, cell encapsulation agents and biomicroreactors. In order to allow GUV:s to reach their full potential, efficient, reliable and flexible generation methods are essential. Existing bulk methods suffer from many drawbacks while proposed microfluidic methods are still in the developing stages. In this report a novel vesicle generation technique is proposed, based on previously published principles.[28][31][29] Vesicles are created from double emulsion templates generated in a single-step flow focusing microfluidic device. The double emulsion generation was characterized and shown to allow generation in both the dripping and jetting regime of droplet generation. The lipid bilayers were created by extraction of excess solvent. The method allowed creation of vesicles in a wide size range (6.5-45µm) at high generation frequencies (300-3500Hz). The created vesicles were characterized using fluorescent methods and quantification of the permeability of the created membranes. Dielectrophoresis (DEP) was proposed and explored as a general method to manipulate generated vesicles. DEP allows for non-invasive, reversible and complex manipulation of vesicles. Patterning and size selective binary sorting using DEP was shown.