Surface immobilization of a short antimicrobial peptide (AMP) as an antibacterial coating

Bacterial infections associated with commonly encountered abiotic surfaces are common threat to patient safety and health care. Antimicrobial peptides (AMPs) immobilization on such surfaces are considered as suitable approach towards addressing this clinical issue. In this study, we evaluate the antibacterial effect of immobilizing a short, pore-forming antimicrobial peptide, KLR (KLLLRLRKLLRR). KLR is covalently linked to polystyrene (PS) surfaces, via its C-terminal using EDC/NHS chemical coupling, and via its N-terminal using maleimide-thiol coupling with a Cysteine added to KLR (CKLLLRLRKLLRR) first. Physicochemical characterization of PS surfaces at each step of modification is carried out using atomic force microscopy, water contact angle measurements, and X-ray photoelectron spectroscopy. Antibacterial efficacy assays demonstrate that immobilized KLR shows excellent antibacterial activity against Gram-negative (E.coli ATCC 25922) and Gram-positive (S.aureus ATCC 25923) bacteria for both the coupling strategies. In addition, the AMP coatings possess no toxicity against mouse fibroblast cells (NIH 3T3).