Abstract
So far almost all studies of biomembrane and lipid membranes have been done using a suspension of manysmall–size vesicles such as large unilamellar vesicles (LUVs).In these studies, the average values of the physicalparameters of LUVs have been obtained from many LUVs, and thereby much information has been lost. Recently wehave proposed a novel method, the single GUV method, for probing function and dynamics of biomembranes/lipidmembranes. In this method we observe and measure changes of structures and physical properties of single giantunilamellar vesicles (GUVs)with a diameter of 10μm in the interaction with various substances, and analyzethese results over many “single GUVs”statistically. This method will reveal detailed elementary processes and alsodetermine their rate constants, which cannot be obtained by the conventional method.In this review, we describe anapplication of the single GUV method to studies on interactions of peptides with lipid membranes, especially interac-tion of antimicrobial peptide magainin 2 with lipid membranes. We show new valuable information on the magainin2–induced leakage of internal contents of liposomes and pore formation in lipid membranes. On the basis of thesedata, we can conclude that the magainin 2 concentration in the membrane interface determine the rate of the poreformation. We also discuss the advantage of the single GUV method in biomembrane research.
