Using Hydrodynamic Forces to Trap and Study Membrane-Associated Molecules in Lipid Bilayers

Abstract

In this presentation I show how hydrodynamic forces can be used to locally trap and move membrane-associated molecules in lipid bilayers. We use the liquid flow through a ∼1 μm pipette to create a localized force field that acts on molecules protruding from the lipid bilayer (see Fig. 1). In addition to introducing the hydrodynamic trap and some of the possibilities and challenges of using this technique on living cells, I will also present examples of using this technique to: (i) vary the concentration of molecules in lipid bilayers, (ii) study intermolecular interactions between different membrane-bound proteins as a function of surface coverage and (iii) induce and study pore formation in lipid bilayers. In particular, I show how the hydrodynamic trap can be used to obtain information about the orientation and mechanical properties of the extracellular domain of the tyrosine phosphatase CD45 involved in the early stages of T-cell immune response.Fig. 1Liquid flow through a conical pipette is used to locally trap molecules in lipid bilayers.View Large Image | View Hi-Res Image | Download PowerPoint Slide