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.

Carboxyl Analogue of Mutacin 1140, a Scaffold for Lead Antibacterial Discovery

“…Semisynthetic analogues of lantibiotics have been produced by chemically modifying lantibiotics (43,44). The most common chemical modification of lantibiotics is through reactions with a free C-terminal carboxyl group.…”

Cationic Antimicrobial Peptides

“…immobilized cecropin-MEL hybrid peptide on a variety of different types of substrates such as amidated polymer brushes, hydrogel and beads [104]; nisin-tethered on block copolymers made of ethylene oxide and propylene oxide monomers [105]; cellulose membranes covered with short bactenecins analogs (Bac2A) [106]; a synthetic -helical CAP, namely E14LKK…”

“…Recent strategies for the immobilization of CAPs on solid surfaces used either: (i) covalent linkage via SPPS [101,106,108,116], thioalkylation [102,104,111], EDC/NHS activation on COOH-enriched surfaces [103,107], disulfide exchange reaction on polymers using thiolated-peptides [105], or (ii) non-covalent methods using highly specific interactions, such as the biotin-streptavidin system [106]. CAPs may be tethered randomly on the solid surfaces or specifically at the C terminus, N terminus or side-chains of the peptides via the -amino group of selected K residues present within the peptide sequences.…”

“…that the covalent immobilization results in the loss of antimicrobial activity [105]. Nisin belongs to the group of lantibiotics [172] and targets the lipid II, which is located on the …”

Biodegradation of Styrene-Butadiene-Styrene Coploymer via Sugars Attached to the Polymer Chain

“…The graphical representation of data (Figure 6) clearly shows the extent of microbial inhibition exhibited by different functionalized SBS polymers. The microbial concentration was determined by measuring the optical density of the broth [19][20][21] at 600 nm after 24 h, the decrease in the optical density is directly proportional to effectiveness of microbial inhibition.…”