Copper sulfide nanoparticle-carrageenan films for packaging application

In this work, to prevent the spoilage of food by microbial contamination, copper sulfide nanoparticles (CuS NPs) with photothermal effect were successfully synthesized by a one-step hydrothermal method and uniformly dispersed in natural carrageenan (Carr) to obtain Carr/CuS films. Photothermal-induced antibacterial testing confirmed that the Carr/CuS film has a broad-spectrum antibacterial activity against Escherichia coli (99.2%) and Staphylococcus aureus (99.9%). Antibacterial test on beef also proved that near-infrared (NIR) irradiation significantly improved the antibacterial ability of the Carr/CuS film against bacteria on the food sample. In addition, compared with the Carr film, the Carr/CuS film with high transparency showed enhanced mechanical properties and thermal stability. The introduction of this NIR-induced strategy is expected to open a new way for broadening the application of antibacterial packaging.