(201f) Fluid and Resistive Supported Lipid Membranes On Nanoporous Metal Films

The study of transmembrane proteins is essential to understand a wide variety of biophysical process that happen across the cell membrane. Generally, supported lipid membranes are used to mimic biological cell membranes and are useful for elucidating membrane function in a controlled laboratory environment. Organization of lipids into membrane architectures can lead to emergent and cooperative behavior of lipids that strongly affects the ion transport and fluidity of the membrane. In addition, incorporation of intact transmembrane proteins/peptides into supported lipid membranes is possible and allows one to controllably study transmembrane protein function. However, interactions between the extra-membrane components of the transmembrane protein with the solid substrate can cause the protein to lose functionality. In order to minimize protein-surface interactions, there is a need to develop a suitable platform that will allow the formation of stable and fluid bilayers. Moreover, the substrate should have desired properties including low resistance and high capacitance in order to electrochemically detect the formation of lipid bilayers. And, finally should also allow intact incorporation of transmembrane proteins. In this report, we have investigated the use of nanoporous metal films that provide a water-filled pocket at the surface for the extra-membrane components of a transmembrane protein. In this presentation, we will show for the first time that lipid membranes on nanoporous noble metal films (Au and Pt) can be both fluid and electrochemically resistive. We make use of several techniques, including ellipsometry, imaging fluorescence microscopy and impedance electrochemical spectroscopy, to characterize the supported lipid membrane architectures. The development of fluid lipid membranes on conducting supports is broadly applicable for studying transmembrane protein function and may potentially be useful for new biosensing, energy harvesting devices and new biomaterial interfaces.