Lipid Membrane adhesion and fusion by Coherent Near-field X-ray Imaging

We propose to study adhesion and onset of membrane fusion using two giant unilamellar vesicles (GUV), controlled by a micropipette setup. By aligning the contact zone in a coherent divergent x-ray wavefield, we will record a magnified holographic fringe pattern which contains information on the nanoscale structure of the adhering bilayers. From least-square fitting of these profiles we will determine important structural parameters, as for example the water layer thickness between two adhering membranes, well below the resolution of optical microscopy. Using methods which we have developed for freely suspended lipid bilayers (black lipid membranes, BLMs), we extract quantitative structural information from the near-field diffraction profile at molecular resolution. Membranes will be in a chamber with x-ray compatible windows, compatible with a wider range of control conditions.