Photolithographic Fabrication of Micro Apertures in Dry Film Polymer Sheets for Channel Recordings in Planar Lipid Bilayers

ABSTRACT: Planar lipid bilayers constitute a versatile method for measuring the activity of protein channels and pores on a single molecule level. Ongoing efforts attempt to tailor this method for detecting biomedically relevant target analytes or for high-throughput screening of drugs. To improve the mechanical stability of bilayer recordings, we use a thin-film epoxy resist ADEX as septum in free-standing vertical bilayers. Defined apertures with diameters between 30 µm and 100 µm were micro-fabricated by photolithography. The performance of these septa was tested by functional reconstitution of the K(+) channel Kcv(NTS) in lipid bilayers spanned over apertures in ADEX or Teflon films; the latter is conventionally used in bilayer recordings and serves as reference. We observe that the functional properties of the K(+) channel are identical in both materials while ADEX provides no advantage in terms of capacitance and signal-to-noise ratio. In contrast to Teflon, however, ADEX enables long-term experimental recordings while the stability of the lipid bilayer is not compromised by pipetting solutions in and out of the recording chamber. Combined with the fact that the ADEX films can be cleaned with acetone, our results suggest that ADEX carries great potential for multiplexing bilayer chambers in robust and reusable sensing devices. GRAPHICAL ABSTRACT: [Image: see text]