Electrophysiological characterization of membrane permeability: from protein channels to nanoparticles

Abstract

Cell membrane permeability is modulated by complex dynamical structures created by objects interacting with the lipid bilayer. Paying attention to the kinetics of ion transport in response to different bioelectrochemical signals, we use planar bilayer electrophysiology to provide a perspective on membrane permeabilization mechanisms that goes from order to disorder as regards to the pore conformational dynamics. We first study stable channels shaped by large transmembrane proteins like OmpF. Next, we provide insights on lipid-peptide interactions leading to the formation of pores by Dynorphin A neuropeptides. Finally, we describe selective ion channels induced by large complex objects like plastic nanoparticles while the global bilayer integrity is maintained. Overall, the particular balance between hydrophobic and hydrophilic interactions is revealed in different ways in each system, either modulating the open and closed states of channels formed by membrane proteins or in the surface functionalization of nanoparticles that rules their interactions with membranes.