Formation of Tethered and Streptavidin-Supported Lipid Bilayers on a Microporous Electrode for the Reconstitution of Membranes of Large Surface Area

Abstract

A new approach for the self-assembly of supported and tethered lipid membranes of large surface area is proposed. The template is a microporous electrode made by anodic etching of aluminum and covered with a monolayer of streptavidin. We show that spontaneous fusion of biotinylated lipid vesicles on the affinity layer is a slow process despite abundant accumulation of lipid material at the template surface. To increase dramatically the efficiency of the self-assembly, fast fusion is provoked with the help of a fusogen solution of poly(ethylene glycol). The extent of fusion is assessed by electrochemical monitoring of the long-range lateral mobility of ubiquinone (coenzyme Q10) in the supported bilayer. Finally, the geometrical characterization of the honeycomb structure at key steps of the self-assembly procedure is performed by electrochemical measurement of the porosity. As expected, the formation of the supported bilayer causes a decrease in the apparent inner diameter of the pores. It is expected that the type of supported lipid membrane built according to the present approach can be adequate for the incorporation of transmembrane proteins in structures that would mimic the membrane stacking found in chloroplasts or mitochondria.