Vesicle deposition and subsequent membrane–melittin interactions on different substrates: A QCM-D experiment

Quartz crystal microbalance with dissipation (QCM-D) technique is one of the most effective methods to monitor the dynamic behaviors of a layer on a solid surface. Moreover, it has been reported recently that it is able to provide a fingerprint for the peptide–membrane interactions. In this work, QCM-D technique combined with computer simulations was employed to investigate the deposition and transformation of vesicles, as well as the subsequent membrane–melittin interactions on different substrates. A range of substrate surfaces, i.e. naked SiO₂ without or with Au/polyelectrolyte coating, were produced. The nature of the substrate determined whether the adsorbed vesicles were present as a high-quality supported bilayer or an assembled vesicle matrix, which consequently influenced the membrane–melittin interactions. It was indicated by the related computer simulations that the lipid packing state of the membrane was a key factor to determine the mechanism of membrane–peptide interactions. Furthermore, this work might be a good example of the application of QCM-D for the exploration of membrane-active peptides.