Insights into the formation of carboxymethyl chitosan-nisin nanogels for sustainable antibacterial activity

To improve the sustainable antibacterial active of nisin, nisin-loaded carboxymethyl chitosan (CMCS-nisin) nanogels (CN NGs) are prepared via a combination method of electrostatic self-assembly and chemical cross-linking. The as-prepared CN NGs are profiled using dynamic light scattering, zeta potential, transmission electron microscopy, fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). We found CN NGs to be spherical and well dispersed, with an average particle diameter of 45 ± 5.62 nm. Besides, the molecular interactions (electrostatic interactions and hydrogen bonding) between nisin and CMCS are the main driving force in the formation of CN NGs, which is demonstrated by FT-IR, XPS and molecular dynamic simulation analysis. Additionally, the CN NGs showed a great nisin-controlled release behavior and the excellent antimicrobial activity against food-borne bacteria. These results suggested that CN NGs have the potential to be used as a promising bio-preservative in food industry.