New Insights into the Molecular Mechanisms of Biomembrane Structural Changes and Interactions by Optical Biosensor Technology

Biomolecular-membrane interactions play a critical role in the regulation of many important biological processes such as protein trafficking, cellular signalling and ion channel formation. Peptide/protein-membrane interactions can also destabilise and damage the membrane which can lead to cell death. Characterisation of the molecular details of these binding-mediated membrane destabilisation processes is therefore central to understanding cellular events such as antimicrobial action, membrane-mediated amyloid aggregation, and apoptotic protein induced mitochondrial membrane permeabilisation. Optical biosensors have provided a unique approach to characterising membrane interactions allowing quantitation of binding events and new insight into the kinetic mechanism of these interactions. One of the most commonly used optical biosensor technologies is surface plasmon resonance (SPR) and there have been an increasing number of studies reporting the use of this technique for investigating biophysical analysis of membrane-mediated events. More recently, a number of new optical biosensors based on waveguide techniques have been developed, allowing membrane structure changes to be measured simultaneously with mass binding measurements. These techniques include dual polarisation interferometry (DPI), plasmon waveguide resonance spectroscopy (PWR) and optical waveguide light mode spectroscopy (OWLS). These techniques have expanded the application of optical biosensors to allow the analysis of membrane structure changes during peptide and protein binding. This review provides a theoretical and practical overview of the application of biosensor technology with a specific focus on DPI, PWR and OWLS to study biomembrane-mediated events and the mechanism of biomembrane disruption. This article is part of a Special Issue entitled: Lipid-protein interactions.