Hydrodynamic concentration of native membrane proteins for on-chip functional studies

Research Project, 2011 – 2014

Supported self-assembly mimics of natural cell membranes have emerged as one of the most important model systems for studies of specific functions of cell membranes. We recently discovered that when applying a bulk flow of liquid above an planar supported lipid bilayer the lipid bilayer and its constituents move in the direction of the bulk flow[Jönsson et al., JACS, 2009]. One striking observation was that by adjusting the bulk flow, membrane-bound molecules could be drastically concentrated at the front of the moving bilayer. In subsequent work, we were able to use the same method to move an SLB over nanoscale apertures[Jönsson et al.,Nano Letters, 2010], potentially providing a solvent-free alternative to conventional black-lipid membranes for studies of protein-controlled molecular transoport reactions. In this project these achievements will be combined with our recent application of evanescent-wave sensing to probe membrane-protein controlled molecular transport [Brändén et al, Biophys J, 2010], with the main aim to concentrate rare membrane proteins to regions containing optically active nanoscale apertures. In this way, we will obtain membrane-protein concentrations high enough for simultaneous label-free studies of both protein-ligand binding and membrane-protein controlled molecular transport reactions at the high surface coverage naturally occurring in cell membranes - which was so far not possible to obtain in systems based on isolated membrane proteins.