Pure lipid vesicles can induce channel-like conductances in planar bilayers.

Typical channel-like current fluctuations were observed in planar lipid bilayers following brief exposure to large concentrations of lipid vesicles devoid of protein. Vesicles, formed by sonication of pure lipids suspended in 150 mM salt solutions, were ejected approximately 0.5 mm from a planar bilayer with a pipette. Over the next several minutes the bilayer conductance changed in ways usually considered to be indicative of reconstituted protein channels including step conductance changes (both up and down), flickering, ion selectivity, and inactivation. This observation demonstrates the need for caution in interpreting conductance changes which occur following ejection of channel-containing vesicles near a membrane.