Highly Electrically Insulating Tethered Lipid Bilayers for Probing the Function of Ion Channel Proteins

Abstract

A method is presented to form gold-electrode-tethered lipid bilayers with exceptionally high electrical resistances. Electrical impedance spectroscopy is used to monitor the bilayer incorporation of a ligand-gated ion channel protein and the modulation of its channel activity by the selective binding of an antibody. Due to the low defect density of the tethered membrane, the effect of a few channels can be resolved thus opening the way to single-channel experiments on this highly stable and versatile platform. In turn, a minute quantity of analyte, here antibodies, can be measured, which is of great interest for bioanalytics.

Two‐Dimensional Protein Crystals for Solar Energy Conversion

“…[ 25 ] tBLMs provide a large barrier to electron transfer, thereby enabling measurement of current changes due to the insertion of single ion channels, but they are not ideal for incorporation of large membrane proteins. [ 26,27 ] To enable electron transfer through the bilayer, we incorporated DSSN+ into unilamellar vesicles and used cyclic voltammetry (CV) to demonstrate increased conductivity across the bilayer when these vesicles were absorbed onto a thiolipid SAM (Supporting Information, Figure S3). To attach the negatively charged PSI crystals to the conductive tBLM, a positively charged tBLM was assembled with an estimated zeta (ζ) potential of 10 mV (Supporting Information, Figure S4).…”

Molecular-scale measurements of electric fields at electrochemical interfaces.

“…Hybrid bilayers of this type have been shown to be excellent electric insulators. 7 For our experiments SAMs were prepared on commercial gold coated coverslips (100 Å. gold thickness) using 1 mM 1-octadecanethiol in absolute ethanol. The coverslips were left in this solution for approximately 48 hours.…”

Real-time high-sensitivity impedance measurement interface for tethered BLM biosensor arrays

“…TETHERED BLM BIOSENSOR tBLMs are ideally suited for reconstituting membrane proteins, in a functionally active and mechanically stable form to be investigated by surface sensitive analytical techniques. The variation of the electrical resistance of tBLMs containing ion channels by ligand binding has been used in biosensors [1][2][3][4][5][6]. Attractive features of this type of biosensors include high amplification of ligand binding by ligand-gated ion channel currents (up to 10 8 ions/sec), high specificity and biocompatibility.…”

“…The resulting aqueous phase between the electrode surface and the lipid bilayer is designed to accommodate the extramembraneous parts of membrane proteins. Tethered lipid bilayers can be formed quickly and easily by self-assembly; they show an exceptionally high mechanical stability [3,5].…”