What Spectro-electrochemical Studies Tell about the Interactions between Antimicrobial Peptides and Biomimetic Membranes at Electrode Surfaces

This feature article provides a summary of spectro-electrochemical studies of selected antimicrobial peptides in model biomimetic membranes deposited at a gold electrode surface. This metal support allows for varying transmembrane potential acting on the membrane and investigating its effect on the properties of the biomimetic membranes and the peptides incorporated into the membrane. The responses of gramicidin (channel-forming peptide), alamethicin (pore-forming peptide), valinomycin (ionophore) and polymyxin (peptide disrupting the outer membrane of the Gram-negative bacteria) to changes in the transmembrane potential are described. The properties of these peptides were investigated in three model membranes: supported bilayer membrane (sBLM), tethered bilayer membrane (tBLM) and floating bilayer membrane (fBLM). Polarization modulation infrared reflection absorption spectroscopy (PM IRRAS) was used to provide information about changes in the orientation and conformation of biomolecules and electrochemical impedance spectroscopy (EIS) was employed to monitor the membrane conductivity. The materials described in this article have been published in several papers over the past decade. This feature article provides a comprehensive and comparative analysis of the assembled information.