Phospholipid/alkanethiol bilayers for cell-surface receptor studies by surface plasmon resonance

Abstract

Supported hybrid bilayer membranes (HBM) composed of a monolayer of phospholipid and a monolayer of alkanethiol associated with a thin gold film on glass are useful as model lipid bilayer membranes for studying membrane receptor-ligand and cell-cell binding events by surface plasmon resonance (SPR). Measurements of specific binding of proteins and lipid vesicles to well-defined HBMs have been performed under conditions of continuous flow using a commercial SPR instrument (BIAcore). HBMs are shown to be stable in flow and to block nonspecific adsorption of proteins to the alkanethiol/gold surface. The use of such supported lipid bilayers in flow provides a means of conducting equilibrium and kinetic studies of models of ligand-cell and cell-cell interactions with receptors or ligands in a membrane environment. Compared to the extended dextran polymer layer that is currently used for surface modification of BIAcore "sensor chips," the described HBMs provide a well-defined surface that will permit less ambiguous modeling of these important biological interactions.