Integration of lysozyme into chitosan nanoparticles for improving antibacterial activity

Lysozyme was integrated into chitosan nanoparticles (CS-NPs) to improve the antibacterial activity. CS-NPs and chitosan-lysozyme nanoparticles (CS-Lys-NPs) were prepared according to the ionic gelation technique and then characterized by average size, zeta potential, polydispersity index (PDI), atomic force microscopy (AFM), fourier transform infrared (FT-IR), small-angle X-ray scattering (SAXS), circular dichroism (CD) and UV-visible spectroscopy. Antibacterial properties were investigated by transmission electron microscopy (TEM) based on observation of the inhibition zone and measurement of the minimum inhibitory concentration (MIC) and minimum bacterial concentration (MBC) of CS-NPs and CS-Lys-NPs against E. coli and B. subtilis. The CS-NPs had particle sizes of 476.2-548.1 nm, while an increase to similar to 488.8 to 613.5 nm was observed upon loading with lysozyme. The results suggested that the integration of lysozyme into CS-NPs enhanced the antibacterial activity against E. coli and B. subtilis, which may show great potential for use in the food industry and other applications in the form of direct addition or incorporation into packaging. (C) 2016 Published by Elsevier Ltd.