Physicochemical and functional properties of chitosan-based nano-composite films incorporated with biogenic silver...

In this study, biogenic AgNPs were synthesize using Nigella sativa extract (NSE) with potential antioxidant activity. The transmission electron microscopy (TEM) image showed spherical AgNPs with biphasic nature and an average particle size 8 nm. AgNPs was then evaluated for their effect on sustained release and film-forming capacity of chitosan. Characterization of the films was done to analyze their physical, mechanical as well as antibacterial properties. The structural change in the films was indicated by FTIR spectra which showed the shift of characteristics peak and modification of the absorbance intensity. Scanning electron micrographs (SEM) showed an uneven distribution of AgNPs all over the CS polymer matrix. Moreover, the mechanical and barrier properties of CS/ Ag nanocomposite films were influenced by the intercalation of AgNPs. The tensile strength and elongation of the films were improved by 8.4-22.5% and 4.4-9.2%, whereas water vapor permeability reduced by 15.23% depending on the concentration of AgNPs. Further, the films showed a pH-dependent sustained release of AgNPs and Ag⁺ ions and significant antibacterial activity. Largely, the excellent antibacterial activity and biocompatibility mark CS-AgNPs composite films a promising material for packaging of food, pharmaceutical, and allied products.