Supported Lipid Bilayers

Abstract

A supported lipid bilayer (SLB) represents a lipid membrane that stably coats a solid surface. One particular property of SLBs is the fact that the bilayer remains in its fluid state, if the SLB is separated by a thin water film from the surface as is the case on hydrophilic substrates. Here, we describe how SLBs are formed by vesicle fusion and membrane spreading and how their properties can be used to study membrane-anchored molecules. Lipid mobility in SLBs is characterized by long-range diffusion. Charged macromolecules such as DNA absorb flat to oppositely charged SLBs and exhibit ideal two-dimensional behaviour as a consequence of unrestricted lateral mobility. Using external electric fields, components embedded or adsorbed to SLBs can be separated and purified by surface electrophoresis. Moreover, surface corrugation, acoustic waves, and photonic approaches enable to manipulate molecules on SLBs. For incorporating transmembrane proteins, so-called polymer-SLBs are introduced that are lifted from the surface by thin polymer films. We discuss the potential of SLBs for chip technologies and future studies on membrane-based processes in synthetic biology.