The global increase of bacterial resistance to antibiotics has led to increasing interest in research focusing on the development and characterization of new antimicrobial agents. One class of promising antimicrobials found in nature are Antimicrobial Peptides (AMP’s) [1]. In contrast to most existing therapeutic antimicrobials, and so it is thought that resistance would be far more difficult to develop to AMP’s. We have designed a novel class of AMP's with the general sequence G(IIKK)nI-NH2, with n-the number of coils of α-helix (n=2-4). In a recent experiment we have studies the interaction of these peptides with floating bilayers intended to mimic gram negtive of eukaryotic membranes, and obesrved changes to membrane structure on binding. In this experiment we wish to extend this preliminary work by studying the concentration dependence of peptide interaction with membranes.