Suspended phospholipid bilayers: a new and versatile biological membrane model

We present a reliable method of forming a fluid phase lipid bilayer suspended underneath a surfactant monolayer at the air-water interface, a novel bacterial membrane mimic. Bilayer formation proceeds by vesicle adsorption and subsequent rupture beneath a monolayer of a cationic surfactant adsorbed at the air-water interface of a laminar ow trough. The laminar flow facilitates buffer exchange beneath the surfactant monolayer, allowing for sequential deposition of vesicles, osmotic rupture and sub-phase contrast variation for neutron reflectometry. As the lipid bilayer formed by this process does not interact with a solid substrate, the suspended bilayer platform is well-suited to studying lipid bilayers including inserted membrane proteins.