Electric signal transfer through nm-thick molecular bilayers

An information transfer mechanism through a molecular bilayer, which does not involve charge/mass transfer or conformational changes of membrane-spanning molecular structures, is proposed. We tested this proposal by measuring changes in the electric potential at a Si/SiOx surface, onto which an artificial bilayer had been constructed, in response to exposure of the adsorbed bilayer to different ambient. The bilayer was comprised of an OctadecylTrichloroSilane (OTS) monolayer, adsorbed onto the Si/SiOx surface and a second layer of stearic acid, deposited on the OTS monolayer by the Langmuir-Blodgett technique. Changes of the band bending (1313) at the Si/SiOx surface in response to exposing the bilayer to different solutions were measured by Kelvin Probe. These changes indicate that external stimuli at the bilayer's exterior induce a change in the electric potential at the bilayer's interior, a change that is sensed at the surface of the Si/SiOx. The mechanism proposed to explain the results is based on electrostatic interactions at the bilayer's exterior with dipole- or monopole-carrying molecules. (C) 2002 Elsevier Science B.V. All rights reserved.