Triple synergistic sterilization of Prussian blue nanoparticle-doped chitosan/gelatin packaging film for enhanced food preservation

To mitigate food spoilage caused by microbial contamination and extend the shelf life of food, antibacterial and eco-friendly biological packaging materials as an alternative to petroleum-based plastics is encouraged. Herein, an innovative and green composite film with triple antibacterial activity has been fabricated by introducing prussian blue nanoparticles (PBNPs) into chitosan (CS)-based films blended with gelatin (Gel) for the preservation of food, named CS/Gel/PB film. Due to the incorporation of PBNPs, CS/Gel/PB film exhibits enhanced mechanical, barrier and water resistance, and thermal abilities. The inherent bacterial trapping and killing capabilities of CS (contact killing), photothermal/photodynamic killing based on the excellent photothermal property of PBNPs under NIR irradiation synergistically facilitate the sterilization against Escherichia coli and Staphylococcus aureus (antibacterial ratio = 99.99 %). The film exhibits outstanding preservation capability in product storage, significantly extending the shelf life of strawberry and pork to 15 and 7 days, respectively. Meanwhile, the cytotoxicity assessment of CS/Gel/PB against HepG2 cells ascertains a cell viability exceeding 96 %, indicating a negligible toxicity level. Additionally, this film also exhibits superior biodegradability (preliminary degradation on the 10th day and completion on the 40th day) compared with PE film. Overall, these properties demonstrate great potential of CS/Gel/PB film as a novel packaging material.