Tethered Lipid Bilayer Membranes: Formation and Ionic Reservoir Characterization

Abstract

Using novel synthetic lipids, a tethered bilayer membrane (tBLM) was formed onto a gold electrode such that a well-defined ionic reservoir exists between the gold surface and the bilayer membrane. Self-assembled monolayers of reservoir-forming lipids were first adsorbed onto the gold surface using gold−sulfur interactions, followed by the formation of the tBLM using the self-assembly properties of phosphatidylcholine-based lipids in aqueous solution. The properties of the tBLM were investigated by impedance spectroscopy. The capacitance of the tBLM indicated the formation of bilayer membranes of comparable thickness to solvent-free black (or bilayer) lipid membranes (BLM). The ionic sealing ability was comparable to those of classical BLMs. The function of the ionic reservoir was investigated using the potassium-specific ionophore valinomycin. Increasing the size of the reservoir by increasing the length of the hydrophilic region of the reservoir lipid or laterally spacing the reservoir lipid results in a...