(360g) Bactericidal Activity of Surface Immobilized Antimicrobial Peptides

Substrates with
antimicrobial functionality have many potential uses including medical devices,
food safety, decontamination and prevention of materials degradation.  Currently
used antimicrobial agents such as metals, chloramines and quaternary ammonium compounds
have a biochemical mode of action that may lead to increased bacterial resistance
after prolonged use.  In contrast, the physical mode of action of antimicrobial
peptides (AMPs) is not expected to induce resistance.  AMPs incorporated into
polyurethane films and coatings exhibited antibacterial activity. After
washing, films lost activity while coated glass fiber filters remained active. Peptide
leaching is required for activity, limiting the length of time the polymer retained
functionality.   To address this limitation, the activity of AMPs covalently-attached
to amine functionalized surfaces was examined.  As proof of concept, AMPs were attached
to magnetic beads.  Activity against both Gram-positive and
Gram-negative bacteria including Acinetobacter baumannii, Bacillus anthracis
sterne and Staphylococcus aureus has been demonstrated.  Potency was
cell?dependent; however, the peptides exhibited activity for all organisms in a
dose-dependent manner, reaching a critical concentration that inhibited growth completely. 
A combination of increased concentration and longer exposure time was required
for activity compared to peptides in solution.  SMAP immobilized to a
glass exhibited activity against E. coli and S. aureus.  A
greater amount of peptide required to exhibit antibacterial behavior than was
needed on magnetic beads. We have demonstrated that antimicrobial functionality
can be imparted to surfaces through covalent attachment of AMPs.  The research
presented here lays the foundation for a new generation of non-leaching
antimicrobial treatments.