Interaction of indolicidin with model lipid bilayer: Quartz crystal microbalance and atomic force microscopy study

The interaction of indolicidin molecules with lipid membrane was studied via in-situ quartz crystal microbalance (QCM) and atomic force microscopy (AFM). From QCM experiments, the interaction of indolicidin with L-α-dipalmitoylphosphatidic acid (DPPA) is found to occur very rapidly. From the AFM experiments, numerous holes ranging from 30 to 100 nm are observed to form initially on the lipid layer by the action of indolicidin. As time went on, the morphology of the DPPA layer become, however, smooth and homogeneous. The result seems to support the earlier view that the aggregated indolicidin should eventually assemble along with the nearby lipid molecules into a closed-packed structure.