Forming lipid bilayer membrane arrays on micropatterned polyelectrolyte film surfaces

A novel method of forming lipid bilayer membrane arrays on micropatterned polyelectrolyte film surfaces is introduced. Polyelectrolyte films were fabricated by the layer-by-layer technique on a silicon oxide surface modified with a 3-aminopropyltriethoxysilane (APTES) monolayer. The surface pK _a value of the APTES monolayer was determined by cyclic voltammetry to be approximately 5.61, on the basis of which a pH value of 2.0 was chosen for layer-by-layer assembly. Micropatterned polyelectrolyte films were obtained by deep-UV (254 nm) photolysis though a mask. Absorbed fluorescent latex beads were used to visualize the patterned surfaces. Lipid bilayer arrays were fabricated on the micropatterned surfaces by immersing the patterned substrates into a solution containing egg phosphatidylcholine vesicles. Fluorescence recovery after photobleaching studies yielded a lateral diffusion coefficient for probe molecules of 1.31±0.17 μm² s^-1 in the bilayer region, and migration of the lipid NBD PE in bilayer lipid membrane arrays was observed in an electric field. Layer-by-layer assembly of polyelectrolyte films on modified glass substrates, followed by micropatterning by deep-UV photolysis though a mask and immersion of the patterned substrates in a solution of lipid vesicles, afforded lipid bilayer arrays (see figure). The migration behavior of charged lipids in the lipid bilayer arrays under an electric field suggests that these patterned supported bilayers may have applications in studies on the manipulation of charged species in the membrane.