Fabrication of Antimicrobial Films Based on Cross-Linked Chitosan Nanocomposite in Food Packaging Applications

This study aims to develop a novel nanocomposite film by modifying chitosan with citric acid and reinforcing it with ZnO nanoparticles. The film’s surface was examined using FE-SEM/EDX and characterized through XPS, TGA, UV–vis, and mechanical testing. 1H NMR and FTIR spectroscopy analysis confirmed the cross-link between chitosan and citric acid. The CS/CA@ZnO nanocomposite film showed a 25% increase in tensile strength and a 5-fold increase in elongation at break, with enhanced barrier properties against water vapor and antioxidant properties compared to pure chitosan. Furthermore, the zone of inhibition of nanocomposite film against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus were 16 ± 1.31, 20 ± 1.25, and 18 ± 0.76 mm, respectively. Moreover, the cell viability of the RAW cell line on the surface of the nanocomposite film was 96.29 ± 1.12%, indicating excellent biocompatibility and holds significant potential for future use in the sustainable food packaging industry.