Controlled solvent-exchange deposition of phospholipid membranes onto solid surfaces

Controlled deposition of lipid bilayers plays a key role in creating supported membranes for biosensing devices and biophysical cell studies. The authors adopt a solvent-exchange method in order to deposit a phospholipid bilayer on solid substrates. The basic concept of deposition is to dissolve phospholipids in isopropanol-water mixtures and to increase water content gradually. Shortly before the onset of the micelle-to-vesicle transition, a lipid bilayer nucleates at the solid surface. They investigate the bulk phase behavior and surface coverage using small angle x-ray scattering and attenuated total reflection-Fourier transform infrared spectroscopy. They find a sequence of transitions from inverted-monomeric-micellar and vesicle phases correlating with an increasing amount of lipid on the adsorption layer. Supported lipid bilayers, prepared using this approach, are homogeneous and fluid. (C) 2010 American Vacuum Society. [DOI: 10.1116/1.3319326]