Formation of supported membranes inside nanoporous aluminium oxide.

J.-B. Larguze and S. Morandat
UMR CNRS 6022 Laboratoire de Gnie Enzymatique et Cellulaire
Compigne University of Technology

Supported model lipid bilayers provided interesting tools for biotechnological applications. We have developed in our laboratory an original substrate for the reconstitution of biomembranes: a nanoporous aluminium oxide electrode. The fusion of small unilamellar vesicles was realised inside the pores to obtain a large surface area membrane. We have investigated different kind of fusion procedures classically found in the literature such as the fusion in presence of calcium or freeze/thaw cycles. The steps of the lipid bilayer formation were followed by Biacore on planar gold surfaces and cyclic voltametry in nanopores. This latter technique allows the electrochemical measurements of the reduction peak of ubiquinone, which is a diffusive electron carrier embedded in the membrane. This permitted to follow the formation of a stable, fluid and continuous membrane along the pores. The quinone electroactive charge was found to be around 1.5C which is consistent with the covering by a lipid bilayer of  5% and  1% of 12m and 60m pores respectively. To increase the membrane surface, a biotin/streptavidin tethered bilayer system has also been investigated. The charge was then 5C for the 60m-long pores and 8,5C for the 40m-long which represents a covering of 8% and 45% of the pores by a membrane.

Keywords: lipid bilayer, cyclic voltametry, nanoporous alumina, ubiquinone