Suspended Planar Phospholipid Bilayers on Micromachined Supports

Abstract

Micromachined structures consisting of an aperture between a buried reservoir and ambient have been produced using the photoresist SU8. The external surface of the structure, surrounding the aperture, was coated in a gold layer to allow surface modification with self-assembled monolayers. These structures were assessed as substrates for the assembly of “suspended” phospholipid bilayers. We report that phospholipid bilayer membranes could be formed over such apertures and that they are highly resistive to the conduction of metal anions (K+). Resistance values are typically found to be ∼1010 Ω (∼106 Ω cm2). These values represent a significant improvement over our membranes supported directly on gold substrates (105 Ω cm2). Fluorescence microscopy images are presented to provide evidence that the lipid bilayer spans the 100 μm aperture. Given the ease of producing large numbers of devices using microlithographic techniques, the proposed structures could form a sensing element for studying membrane transport phenomena in general and for ion-channel assays in particular.