Sustained, coupled electrical and mechanical oscillations in a bimolecular lipid membrane in the presence of inorganic ions

Abstract

Bimolecular lipid membranes of oxidized cholesterol or phosphatidylethanolamine separating bathing solution compartments of potassium ferricyanide and potassium iodide can be set into regular, sustained electrical oscillations when the pH's of the two compartments are adjusted to 5 and 10, respectively. The period of the oscillations are in the order of 30 sec, and the amplitudes are about 30–40% of the self electromotive force, or conduction in an applied field. A mechanical oscillation of the membrane can be detected simultaneously, which has the same period as the electrical.