Rational Design of Novel Cationic Peptide for Antimicrobial and Antifouling Applications

Antifouling, the undesirable adhesion of organisms to a surface, is nowadays a major problem worldwide for health-care, energy and water. Different strategies, such as enzymatic degradation, chemical modification and sonication, which change the surface energy of a surface, were suggested to prevent biofouling. However, a sufficient solution still does not exist because of environmental concerns, limitation to specific surfaces, low stability, short term activity, expensive synthesis or complicated fabrication procedures. Peptides are easy to synthesize, biocompatible in nature and can provide ordered structure due to spontaneous self-assembly. Recent research in our group on peptide-based antifouling materials showed that a tripeptide, containing 3,4-dihydroxyphenyl alanine (DOPA) and two para-fluoro phenylalanine shows good antifouling properties. In this peptide design, the amino acid phenylalanine directs the self-assembly of the peptide by aromatic interactions, the amino acid para-fluoro phenylalanine mimic the non-stick properties of fluorinated polymers and the amino acid DOPA attaches the peptide to the surface. This amino acid is abundant in mussel adhesive protein (MAP). Trying to improve the antifouling properties of this tripeptide, we designed a peptide containing biocidal cationic residues. Cationic peptides, which contain positively-charged amino acids, can interact with the bacterial membrane due to its negative charge and therefore have antibacterial property. For this reason, we chose to incorporate the amino acid lysine in the peptide sequence. In addition, we used multiple para-fluoro phenylalanine and lysine since we assumed that this will enhance the antifouling activity of the peptide. Our results show that a peptide comprising ten lysine and ten phenylalanine residues self-assembles into a coating on the surface and have antifouling and antibacterial activity. This peptide can be applied as an antifouling coating on medical devices, hospital equipment and water desalination facilities.