Preparation and Characterization of Supported Lipid Bilayers for Biomolecular Interaction Studies by Dual Polarization Interferometry

Analysis of peptide/protein–membrane interactions is central to delineating the regulatory mechanisms of many membrane-mediated biochemical processes associated with receptor signaling, molecular transport, membrane trafficking, cell–cell communication, organelle dynamics, membrane destabilization by cytotoxic toxins, and antimicrobial peptides. Among a wide-range of biophysical methods for studying the membrane interaction, dual polarization interferometry (DPI) combines supported lipid bilayers and a highly sensitive optical waveguide interferometer. The unique features of evanescent field sensing and optical phase difference measurement in DPI thus provide quantitative analysis of changes in molecular mass and molecular packing order of the membrane. The use of simpler membrane model systems to mimic the complex native biomembrane demands robust methods to prepare stable lipid bilayers particularly in terms of reproducible structural organization. With these unique features, DPI has been used to screen key parameters to control the successful formation of lipid bilayers via vesicle fusion and to characterize biomolecule/membrane interactions simultaneously with the reciprocal impact of the molecular binding on the destruction of membrane structure throughout the dynamic association–dissociation process. This multiplex analysis of the dynamic changes in lipid organization and molecular mass has provided new insight into the molecular mechanisms of membrane-active peptides and proteins especially in relation to changes in bilayer structure associated with the biomembrane binding and disruption.