A chip-based array for high-resolution fluorescence characterization of free-standing horizontal lipid membranes under voltage clamp. Issue 15 (15th July 2022) - Ensslen, Tobias
Abstract : A chip-based microelectrode cavity array facilitates simultaneous high resolution optical and electrical analysis of free-standing lipid membranes. Abstract : Optical techniques, such as fluorescence microscopy, are of great value in characterizing the structural dynamics of membranes and membrane proteins. A particular challenge is to combine high-resolution optical measurements with high-resolution voltage clamp electrical recordings providing direct information on e.g. single ion channel gating and/or membrane capacitance. Here, we report on a novel chip-based array device which facilitates optical access with water or oil-immersion objectives of high numerical aperture to horizontal free-standing lipid membranes while controlling membrane voltage and recording currents using individual micropatterned Ag/AgCl-electrodes. Wide-field and confocal imaging, as well as time-resolved single photon counting on free-standing membranes spanning sub-nanoliter cavities are demonstrated while electrical signals, including single channel activity, are simultaneously acquired. This optically addressable microelectrode cavity array will allow combined electrical–optical studies of membranes and membrane proteins to be performed as a routine experiment.