Iron oxide magnetic nanoparticles functionalized by nisin

Abstract

Over the last decades iron oxide magnetic nanoparticles, mostly magnetite (Fe3O4) and maghemite (γ–Fe2O3), have increasingly attracted attention as an efficient tool in various fields of application [1]. Here, we present the preparation and characterization of iron oxide magnetic nanoparticles functionalized by nisin. Nisin is naturally produced by Lactococcus lactis subsp. lactis as a small cationic peptide composed of 34 amino acid residues and is a well-known bacteriocin approved as a food additive for food preservation [2]. Iron oxide magnetic nanoparticles were prepared by the co-precipitation method and characterized by X-ray diffraction method. Magnetic nanoparticles were stabilized by citric, ascorbic, gallic, or glucuronic acid coating and were functionalized by nisin using a simple and low-cost adsorption method (Fig. 1). Nisin loading was confirmed by FT-IR spectra, thermogravimetric analysis, and dynamic light scattering methods. Nisin-loaded iron oxide magnetic nanoparticles were stable for at least six weeks as judged by zeta-potential and hydrodynamic diameter measurements. The functionality of nisin-loaded iron oxide magnetic nanoparticles was demonstrated on Grampositive bacteria. Functionalized nanoparticles could find their application in innovative and emerging technologies as antimicrobials.