Applied Chemistry

Biography

Biography: Charafeddine Jama

Abstract

Setting up antimicrobial food packaging by nisin adsorption on plasma-treated surfaces depends on the interactions between the peptides and those surfaces. In order to investigate the factors affecting such adsorption, the native hydrophobic low density polyethylene (LDPE) was modified to generate hydrophilic surfaces using Argon / Oxygen (Ar/O2) plasma, nitrogen (N2) plasma and plasma-induced graft polymerization of acrylic acid (AA). The films were studied by various characterization techniques. The chemical surface modification was confirmed by X-ray photoelectron spectroscopy (XPS), the wettability of the surfaces was evaluated by contact angle measurements, the surface charge was determined by the zeta potential measurements and the changes in surface topography and roughness were revealed by atomic force microscopy (AFM). Nisin was adsorbed on the native and the modified surfaces. The antibacterial activity, the nisin adsorbed amount and the peptide distribution were compared for the four nisin-functionalized films. The roughness measurements highlighted the difference observed between surface topographies before and after nisin adsorption. The highest antibacterial activity was recorded on the Ar/O2 film, followed by AA grafting then by nitrogen plasma and the lowest activity was on the native film. The observed antibacterial activity was correlated to the type of the surface, hydrophobic and hydrophilic interactions, nisin distribution on the surfaces, surface charge, surface topography and amount of nisin adsorbed on the surfaces.