Synthesis and antibacterial activity of nisin‐containing block copolymers

Abstract

Nisin, an antibacterial peptide proven to be an effective inhibitor of Gram‐positive bacteria, was incorporated into novel block copolymer constructs and tested for retained antibacterial activity. Covalent coupling was achieved by chemical modification of the N‐terminal isoleucine to introduce a thiol group. Thiolated‐nisin derivatives were then linked to poly[ethylene oxide]‐poly[propylene oxide]‐poly[ethylene oxide] (PEO‐PPO‐PEO) triblocks that had been end‐activated such that terminal hydroxyl groups of the PEO chains were replaced with pyridyl disulfide moieties. The nisin‐containing block copolymers were separated from free nisin by dialysis and showed antimicrobial activity against the Gram‐positive indicator strain Pediococcus pentosaceus. The contribution to antimicrobial activity from nisin that was covalently linked was not distinguished from the contribution of nisin that had associated with the PEO‐PPO‐PEO triblocks through noncovalent interactions. However, nisin that was covalently linked showed activity upon reduction of the disulfide bond and release from the end‐activated PEO. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009