Antimicrobial peptides (AMPs) are a class of natural compounds that hold promise for the development of antibiotics. However, they are not intrinsically useful because they are easily broken down by proteolytic enzymes in the body and may initiate immune responses. Phillip B. Messersmith and his team at Northwestern University have recently developed a novel method of producing useful antimicrobial products inspired by AMPs. In order to overcome the disadvantages of natural AMPs, they construct peptide chains comprised of N-substituted glycine type synthetic amino acids. Since these novel amino acids do not exist in nature, they do not initiate an immune response and are not susceptible to degradation by proteolytic enzymes. However, they share enough characteristics with natural amino acids that chains of the synthetic amino acids, called peptoids, do mimic the folding habits of natural peptides. Messersmith's group created a series of peptoids that adopt helical folding patterns similiar to natural AMPs; they dubbed the synthetic counterparts ampetoids. When immobilized to a surface by bonding, the surface becomes passively antimicrobial. The ampetoids developed by Messersmith and his team have demonstrated a high degree of antimicrobial capability. Moreover, since the active mechanism of AMPs (and ampetoids as well) relies on forming "barrel stave" type punctures in microbial cell membranes, pathogens do not easily develop immunity to their effects.
Most antimicrobial surface coatings are petroleum-based polymers or contain harmful and expensive chemicals (e.g., quaternary ammonium compounds and silver, respectively). A surface treatment based on ampetoids would not necessarily contain such components and could be made from renewable resources.
Conventional antimicrobial surface coatings cannot always prevent the growth of microbial biofilms either due to resistance or lack of inherent efficacy. Surface coatings containing immobilized ampetoid may be more effective at preventing the growth of pathogens on medical devices, hospital equipment, food packaging, and fresh water containers.Edit Summary