(228eq) Development and Characterization of Collagen Substrates to Study Antimicrobial Peptide Tethering Using QCM-D

The success of chronic wound scaffolds is severely threatened by infection, but current methods to manage infection are toxic, impede tissue regeneration, and may promote antimicrobial resistance. Antimicrobial peptides (AMPs) are promising as alternative chronic wound therapeutics because of their function in the innate immunity of several species, including broad-spectrum antimicrobial activity and immunomodulatory functions, and their unique mechanisms leading to a low likelihood of promoting antimicrobial resistance. Unfortunately, clinical application of AMPs is hindered by their fast degradation and toxicity at high concentrations in vivo. Tethering, or binding AMPs to surfaces has been shown to increase stability and reduce toxicity. Previously, we studied AMP tethering onto inorganic and metallic surfaces using quartz-crystal microbalance with dissipation (QCM-D), a real-time method for characterizing mass and film rigidity changes on a surface, and coupled it with antimicrobial assays. However, QCM-D methods for studying AMP tethering onto relevant biopolymer surfaces have not been developed. Our overall goal is to develop a QCM-D platform to study AMP tethering onto collagen, a prevalent biopolymer in wound scaffolds, and assess AMP bioactivities. For this, we chose human-derived AMP LL37 because it has well-characterized antimicrobial and wound healing activities, and modified it with a collagen binding domain (CBD-LL37) for binding specificity. Here, we characterized adsorbed collagen films using QCM-D in terms of thickness, concentration, substrate, morphology and crosslinking, studied real-time CBD-LL37 binding to these films, and developed ex situ antimicrobial assays to study bound CBD-LL37 bioactivity. These results demonstrate QCM-D versatility in studying AMP-biopolymer tethering for development of antimicrobial scaffolding materials.