1-Dodecanethiol assembly on polycrystalline gold electrodes at fixed positive potentials has been investigated by chronoamperometry and electrochemical quartz crystal microbalance and the films formed characterized by cyclic voltammetry and electrochemical impedance spectroscopy. It was found that 1-dodecanethiol adsorption on gold is enhanced by application of positive potentials to the electrode surface and that adsorption proceeds faster than in the case of open circuit deposition. Compact defect-free monolayers of capacitance values of 1.1 ± 1.6 mF cm À2 are produced in time intervals as short as 100 s, with no roughness, as demonstrated for the first time by electrochemical impedance analysis. Control of surface potential during alkanethiol assembly appears to improve monolayer quality and to allow for shorter assembly periods. Monolayers can be removed by cycling in alkaline solution or in dilute sulfuric acid. These results are important for the fast construction of defect-free bilayers.

A robust platform providing a fluid lipid bilayer is in great demand not only for specific basic research on membrane proteins, but also for related applications. Here we present electrically sealing solventfree bilayer lipid membranes spanned over arrays of cylindrical nanopores. The nanopores are milled through thin Si 3 N 4 diaphragms using a focused ion beam (FIB). Scanning electron microscopy (SEM) and atomic force microscopy (AFM) reveal pores with regular shapes and inter-pore spacing. Nanopore-spanning bilayer lipid membranes (npsBLMs) are formed reproducibly by directed fusion of giant unilamellar vesicles (GUVs) to the pore-containing diaphragms. The arrays of npsBLMs exhibit electrical resistances in the GU range, lifetimes of up to several days, and breakdown voltages above 250 mV. Perfusion robustness of the npsBLMs and low aspect ratio of the nanopores allow easy access to both sides of the bilayers. npsBLM conductance in the presence of the pore-forming toxin gramicidin D increases depending on the concentration levels. Peptide-to-lipid molar ratios can reach as high as 1 : 23. Recordings of ionic currents through alamethicin channels are possible with single-channel resolution after dielectric passivation of the substrates. This demonstrates the applicability of the platform to biophysical research of membrane proteins as well as pharmaceutical drug screening assays.

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