Activity Retention after Nisin Entrapment in a Polyethylene Oxide Brush Layer

Abstract

The cationic, amphiphilic peptide nisin is an effective inhibitor of gram-positive bacteria whose mode of action does not encourage pathogenic resistance, and its proper incorporation into food packaging could enhance food stability, safety, and quality in a number of circumstances. Sufficiently small peptides have been shown to integrate into otherwise nonfouling polyethylene oxide (PEO) brush layers in accordance with their amphiphilicity and ordered structure, including nisin, and we have recently shown that nisin entrapment within a PEO layer does not compromise the nonfouling character of that layer. In this work we test the hypothesis that surface-bound, pendant PEO chains will inhibit displacement of entrapped nisin by competing proteins and, in this way, prolong retention of nisin activity at the interface. For this purpose, the antimicrobial activity of nisinloaded, PEO-coated surfaces was evaluated against the gram-positive indicator strain, Pediococcus pentosaceous. The retained antimicrobial activity of nisin layers was evaluated on uncoated and PEO-coated surfaces after incubation in the presence of bovine serum albumin for contact periods up to 1 week. Nisin-loaded, uncoated and PEO-coated samples were withdrawn at selected times and were incubated on plates inoculated with P. pentosaceous to quantify nisin activity by determination of kill zone radii. Our results indicate that nisin activity is retained at a higher level for a longer period of time after entrapment within PEO than after direct adsorption in the absence of PEO, owing to inhibition of nisin exchange with dissolved protein afforded by the pendant PEO chains.

Nisin anchored cellulose nanofibers for long term antimicrobial active food packaging

“…10 Converse to antibiotics, their mode of action does not encourage pathogenic resistance, hence, suppresses the evolution of new infectious diseases. 11 In last decade, nisin has been either incorporated into various polymer matrices, for instance polyethylene brushes, 12 LDPE, 13 polypropylene, 14 soy protein, 15 or starch, 16 or in coatings over them [17][18][19] _ENREF_17. However, these direct applications have been limited in their benecial effects and exhibit a loss in long-term activity.…”

Crystallite dissolution in PEO-based polymers induced by water sorption

“…Water sorption and diffusion in amphiphilic block copolymers (BCPs) are of interest for a wide range of applications 4 , including fuel cells 5 and air batteries [6][7][8][9] , CO2 separation [10][11][12][13] , water desalination 14,15 , food packaging 16,17 , drug delivery 18 , and biomedical implants 19 . Proton exchange membrane fuel cells and air batteries rely on a solid polymer electrolyte to separate the electrodes and conduct ions.…”

Active Packaging Coatings

“…The authors demonstrated that the coating treatment did not affect the mechanical properties of poly(lactic acid); however, the gas barrier properties measured as CO2 permeation were adversely affected. In another work, the antimicrobial peptide nisin was entrapped in polyethylene oxide brushes grown on silane modified silicon wafers [61]. It was hypothesized that the polyethylene oxide brushes would protect nisin from being eluted by foreign proteins and subsequently losing its activity.…”