Fabrication of an antibacterial system of arginine-modified chitosan with AgNPs-loaded montmorillonite for food preservation

Ag-based materials have potent antibacterial effects, but their potential toxicity problems should not be underestimated, so it is urgent to construct a safe and non-resistant dual antibacterial system. In this study, we utilized tea polyphenols (TPs) and montmorillonite (MMT) to control the growth of silver nanoparticles (AgNPs). Then, we combined the AgNPs with arginine to construct a synergistic antibacterial system of arginine-modified chitosan-assisted AgNPs-loaded MMT (ACS/G/AgNPs@MMT). The results showed that AgNPs with a uniform dispersion of 6.72 ± 4.66 nm and ACS with a grafting degree of 0.153 were successfully prepared, and the synergistic antibacterial effect between ACS and AgNPs@MMT was verified by the FIC index, and the antibacterial rate could still reach 99.9 % when the additions of ACS and AgNPs@MMT were reduced by 75 % and 79.1 %, respectively. The ACS/G/AgNPs@MMT-2 composite film exhibited excellent mechanical properties, water vapor/UV barrier properties, antioxidant activity, degradation properties, and biosafety. In addition, the synergistic effect enabled the ACS/G/AgNPs@MMT-2 film to achieve antibacterial rates of 99.24 ± 0.19 % against E. coli and 99.49 ± 0.40 % against S. aureus, and the film exhibited excellent long-lasting antibacterial performance due to the slow release of Ag+ (only about 11.27 % of Ag+ was released in 20 days). Finally, the ACS/G/AgNPs@MMT-2 film could significantly improve the food preservation ability. In conclusion, this study indicates that the film could be used as a novel antibacterial packaging material.