SUPPORTED PHOSPHOLIPID ALKANETHIOL BIOMIMETIC MEMBRANES - INSULATING PROPERTIES/

A novel model lipid bilayer membrane is prepared by the addition of ph ospholipid vesicles to alkanethiol monolayers on gold. This supported hybrid bilayer membrane is rugged, easily and reproducibly prepared in the absence of organic solvent, and is stable for very long periods o f time. We have characterized the insulating characteristics of this m embrane by examining the rate of electron transfer and by impedance sp ectroscopy. Supported hybrid bilayers formed from phospholipids and al kanethiols are pinhole-free and demonstrate measured values of conduct ivity and resistivity which are within an order of magnitude of that r eported for black lipid membranes. Capacitance values suggest a dielec tric constant of 2.7 for phospholipid membranes in the absence of orga nic solvent. The protein toxin, melittin, destroys the insulating capa bility of the phospholipid layer without significantly altering the bi layer structure. This model membrane will allow the assessment of the effect of lipid membrane perturbants on the insulating properties of n atural lipid membranes.