  Artificial bilayer lipid membranes (BLMs), along with patch-clamped
membranes, are frequently used for functional analyses of membrane proteins. In
both methods, the electric properties of membranes are characterized by only
one parameter, namely, transmembrane potential. Here the construction of a
novel BLM system was reported, in which membrane voltages can be controlled in
a lateral direction in addition to conventional transmembrane direction. A
microaperture was fabricated in a Teflon film and Ti electrodes were evaporated
around the aperture. BLMs were reproducibly formed in the aperture without
being affected by the presence of the electrodes. The application of a lateral
voltage induced no significant changes in the electric properties of the BLMs,
such as baseline current, transmembrane resistance, and transmembrane
capacitance. In contrast, lateral voltages clearly affected the activities of
biological ion channels, suggesting that the lateral voltage might be a useful
parameter for analyzing channel activities. The present Teflon-based system in
which multidirectional voltages can be applied to BLMs represent a promising
platform for the analysis of underlying functional properties of membrane
proteins.
