Quartz Nanopore Membranes for Suspended Bilayer Ion Channel Recordings

Abstract

A method is described for fabricating 25-75 mum thick fused quartz membranes containing a single conical shaped nanopore (orifice radius ranging from 10 to 1000 nm). The quartz nanopore membrane (QNM) provides an excellent solid support structure for lipid bilayers in ion channel recordings due to the large electrical resistivity of fused quartz. Electrical measurements demonstrate that the leakage current through 1,2-diphytanoyl-sn-glycero-3-phosphocholine (DPhPC) bilayers suspended across a 500-1000 nm radius QNM orifice is immeasurably small, corresponding to a bilayer resistance greater than 10(12) ohms. Translocation of single-stranded DNA oligomers (poly dA 50-mer and poly dA 20-mer) through a protein ion channel (alpha-hemolysin) reconstituted in a DPhPC bilayer suspended across the QNM orifice is demonstrated.