Multivalent Ligand-Receptor Interactions on Planar Supported Membranes An On-Chip Approach

Abstract

Since their initial fabrication two decades ago by McConnell and coworkers, fluid supported phospholipid bilayers (SLBs) have played a key role in the development of nanoscale assemblies of biological materials on artificial supports. 1,2 The reason for this is quite straightforward. SLBs can serve as biomimetics for chemical and biological processes which occur in cell membranes. A thin aqueous layer (approximately 1 nm thick) is trapped between the bilayer and the underlying support (Figure 6.1). Thiswater layer acts as a lubricant allowing both leaflets of the bilayer to remain fluid. 3–10 Consequently, planar supported membranes retain many of the physical properties of free vesicles or even native cell surfaces when the appropriate recognition components are present. 4 Specifically, SLBs are capable of undergoing lateral rearrangements to accommodate binding by aqueous proteins, viruses, toxins, and even cells. 11 As substrate supported entities, they are convenient to study by a host of interface-sensitive techniques and are far less fragile than either unsupported membranes or full-blown cellular systems.