Unraveling dominant surface physicochemistry to build antimicrobial peptide coatings with supramolecular amphiphiles

With the increasing threat from antibiotic-resistant bacteria, surface modification with antimicrobial peptides (AMP) has been promisingly explored for preventing bacterial infections. Little is known about the critical factors that govern AMP-surface interactions to obtain stable and active coatings. Here, we systematically monitored the adsorption of a designer amphipathic AMP, GL13K, on model surfaces. Self-assembly of the GL13K peptides formed supramolecular amphiphiles that highly adsorbed on negatively charged, polar hydroxyapatite-coated sensors. We further tuned surface charge and/or surface polarity with self-assembled monolayers (SAMs) on Au sensors and studied their interactions with adsorbed GL13K. We determined that the surface polarity of the SAM-coated sensors instead of their surface charge was the dominant factor governing AMP/substrate interactions via hydrogen bonding. Our findings will instruct the universal design of efficient self-assembled AMP coatings on biomaterials, biomedical devices and/or natural tissues. Surface polarity via hydrogen bonding dominates interactions with supramolecular nanofibrillar amphiphiles formed by GL13K antimicrobial peptides.