Biophysical characterization reveals the similarities of liposomes produced using microfluidics and electroformation

Abstract

Giant Unilamellar Vesicles (GUVs) are a versatile tool in many branches of science, including biophysics and synthetic biology. Octanol-Assisted Liposome Assembly (OLA), a recently developed microfluidic technique enables the production and testing of GUVs within a single device under highly controlled experimental conditions. It is therefore gaining significant interest as a platform for use in drug discovery, the production of artificial cells and more generally for controlled studies of the properties of lipid membranes. In this work, we expand the capabilities of the OLA technique by forming GUVs of tunable binary lipid mixtures of DOPC, DOPG and DOPE. Using fluorescence recovery after photobleaching we investigated the lateral diffusion coefficients of lipids in OLA liposomes and found the expected values in the range of 1 μm 2 /s for the lipid systems tested. We studied the OLA derived GUVs under a range of conditions and compared the results with electroformed vesicles. Overall, we found the lateral diffusion coefficients of lipids in vesicles obtained with OLA to be quantitatively similar to those in vesicles obtained via traditional electroformation. Our results provide a quantitative biophysical validation of the quality of OLA derived GUVs, which will facilitate the wider use of this versatile platform.

Multifunctional Nanotheranostics for Overcoming the Blood–Brain Barrier

“…The type of liposomes produced for drug delivery is determined by the preparation method, including 1) unilamellar vesicles (ULVs) having one bilayer membrane (including small, large, and giant unilamellar vesicles), 2) oligolamellar vesicles (OLVs) made of 2 to 5 bilayer membranes, and 3) multilamellar vesicles (MLVs) containing five or more bilayer membranes. [185,186] For medical applications, liposomes are synthesized through a variety of techniques, including heating, [187] spray-drying, [188] curvature tuning, [189] osmotic shock, [190] localized IR heating, [191] dual asymmetric centrifugation, [192] lyophilization, [193] hydration on glass beads, [194] gel-assisted hydration, [195] hydration in microfluidics, [196] electroformation in microfluidics, [197] transient membrane ejection, [198] continuous droplet interface crossing encapsulation (cDICE), [199] stationary phase interdiffusion method, [200] and pulsed microfluidic jetting. [201] Figure 15.…”