Marcus Lindemann

• During this thesis three different projects have been combined to gain insight into the technical application of Membrane-Protein Matrices. First, a miniaturized, automated "patch-clamp-on-a-chip" system has been adapted for measurements on planar lipid bilayers. The functional setup shows the expected advantages of low stray capacitances with determined 10pF, and complete integration into the data processing environment. Using giant unilammellar vesicles for automated giga-seal formation over a micrometer-sized aperture in a glass chip, proved to be a promising technique for further automation and parallelization to facilitate high-throughput screening of pharmaceutical substances. Second, a calcein efflux assay for liposomes provides an analytical method to investigate the functional incorporation of pore forming proteins into lipid bilayers. It allows quick testing the quality of porin batches prior to time consuming single molecule measurements on planar lipid membranes. Donnan potential experiments on liposomes revealed the competition of two processes in the formation of a zeta potential. It is determined by the concentration gradient of the encapsulated polyelectrolyte and by the number as well as by the charge of the incorporated porins. The Donnan potential allows to couple otherwise uncharged liposomes to an external electric field. Furthermore the Donnan potential gives us another tool to investigate the permeability of lipid membranes. By the characterization of the Donnan potential we can study the diffusion of ions across lipid membranes through channel proteins as well as the permeability of porins for macromolecules. Third, during the industry project "Development of a biological fuel-cell", a battery test bed has been set up and operated. Measurements were done with a zinc/air battery, incorporating PowerZyme's proprietary Active Transport Membrane. Several graphical user interfaces for data acquisition and data analyses have been created.