Supported Lipid Membranes at the Au‐Buffer Interface by Solvent Exchange: The Effect of Initial Solvent Concentration

Abstract

The recently introduced solvent‐assisted lipid bilayer (SALB) formation method has proved a fast, simple, and versatile alternative to vesicle fusion in forming membrane‐mimicking platforms on solid supports such as SiO2, TiO2, graphene, and Au. This confers SALB with a broad applicability for developing biomaterial coatings for implants, biomimetic cell culture platforms, and cancer diagnostics. Although significant understanding on the interplay of the parameters controlling SALB (type of solvent, lipid concentration, and flow rate) has been achieved to date, there still exists several unexplored specific questions to be tackled. Herein, the question of how the initial solvent concentration affects the formation and organization of (zwitterionic) lipid membranes formed by SALB on Au surfaces is addressed. Using quartz crystal microbalance with dissipation monitoring, differences in frequency and dissipation responses are observed upon dissolving the lipid compound dimyristoyl phosphatidylcholine (DMPC) in either pure isopropanol or mixtures of different volume ratios of isopropanol and aqueous buffer. At high and medium initial solvent concentrations, thin and rigid supported lipid bilayers (SLBs) are typically formed at the Au–liquid interface, irrespective of the lipid structures formed in bulk, whereas at low solvent concentrations, irreversible vesicle adsorption takes place hindering the homogeneous SLB formation.