Novel chitosan films with laponite immobilized Ag nanoparticles for active food packaging.

Silver nanoparticles (AgNPs) are a kind of excellent antimicrobial agent, but the application is limited in food field due to easy leakage. In this work, for the first time, laponite immobilized silver nanoparticles (LAP@AgNPs) were synthesized with quaternized chitosan as green reductant, in which AgNPs were embedded in the interlayer of laponite due to confinement effect. Subsequently, chitosan-based films with LAP@AgNPs were prepared for keeping litchis fresh. The results show that only about 5.6% of AgNPs were released from the films with laponite, which were much lower than those films without laponite (about 29.1%), and physicochemical properties of the films were improved due to the suitable addition of laponite. Furthermore, although the films showed very low toxicity to cells, they exhibited good antimicrobial activity and effectively extended the storage life of litchi as a packaging. Hence, the research provides the potential application for silver nanoparticles in food field.