Micro- and nanostructured devices for investigating biomolecular interactions

Cell membrane receptors and ion channels are essential in many different cellular processes. To analyse the activity of membrane proteins in vesicles and biological cells, we fabricated micro- nanostructured chips, enabling the application of electrophysiology and fluorescence-based techniques. A SU-8 biochip was developed for simultaneously micromanipulating and investigating optically and electrically individual vesicles in a microfluidic channel. Lipid vesicles were transported, positioned by electrophoretic movement on a micrometer sized aperture, and fused to form a planar suspended membrane, which is suited to study ion channel activity. Aiming to investigate G protein-coupled receptor signaling pathways in native-like environment, we developed a method for producing well-oriented planar cell membrane sheets on silicon films containing nanoaperture arrays. The accessibility of extracellular and cytosolic surfaces was demonstrated by targeting membrane constituents side-specifically with fluorescent markers. Our approach can be applied for studying membrane proteins from a large variety of cells and cellular organelles using chip-based screening assays.