Stable lipid bilayers based on micro- and nano-fabrication

In this review, we will discuss our recent approaches for improving the mechanical stability of free-standing bilayer lipid membranes (BLMs) by combining with BLM formation and micro- and nano-fabrication techniques. BLMs were prepared across a microaperture fabricated in silicon (Si) chips or nanoporous alumina films, and their mechanical stability and electric properties were investigated. BLMs spanned over the porous alumina showed background noise currents small enough for recording activities of low-conductance channels, though further stability enhancement of porous alumina films was necessary. BLMs suspended in a thin Si3N4 septum showed a dramatic improvement of BLM stability. The BLMs were resistant to a voltage of +/- 1V and the membrane lifetime was 15-43h with and without incorporated channels. The membrane containing gramicidin channel exhibited tolerance to repetitive solution exchanges, though the electric properties of the BLMs are necessary to be improved. The realisation of BLMs having both mechanical stability and proper electric properties will open up a variety of applications including highly sensitive biosensors and high-throughput drug screenings for ion channels.