Evidence for membrane flow through pores in stacked phospholipid membranes

Abstract

We present evidence for an inter-bilayer transport mode of lipid molecules in solid-supported double bilayer membranes via membrane defects. The observation of avalanche rupturing in isolated membrane areas of flat giant unilamellar vesicles, i.e., double bilayers, in the distal (with respect to the solid support) bilayer revealed migration of the membrane material between the stacked bilayers, which we can explain by the presence of defects. The presence of the interconnections was indirectly observed by monitoring the area development of the isolated membrane patches during rupturing. These new findings can help to better describe the dynamic processes in biological structures, featuring stacks of phospholipid bilayers, such as mitochondrial shape dynamics.