Inherently Antibacterial Hydrogels: Altering Activity via Tryptophan/Arginine Interactions

Hydrogels are heavily hydrated materials that show considerable promise as artificial extracellular matrices for use in tissue regenerative therapies. The development antibacterial hydrogels has been of great interest to the hydrogel research community as a means to combat the threat of infection during material implantation. We have developed MAX1, a self-assembling β-hairpin peptide hydrogel whose surface exhibits inherent antibacterial activity against several pathogens prevalent in hospital settings. Under physiological conditions, MAX1 self-assembles into a highly crosslinked, mechanically rigid hydrogel whose solvent-exposed fibrils display positive charge, which is thought to be important for antibacterial activity. This study aims to investigate the contributions of a cation-π interaction to the antibacterial activity of a newly designed peptide hydrogel. Cation-π interactions are a common feature of many antibacterial peptides, where they assist in the disruption of bacterial membranes. Thus, a new β-hairpin peptide (RWMAX1) was designed, incorporating a cross-strand Tryptophan/Arginine pair, in the hope of creating a more potent antibacterial hydrogel. The folding and self-assembly properties were assessed using circular dichroism and rheology and the antibacterial activity was investigated against E. coli and S. aureus. Supported by the Beckman Foundation