A MoS₂QDs/chitin nanofiber composite for improved antibacterial and food packaging

Chitin nanofiber has potential application as antibacterial nanocomposite material because of its inherent biocompatibility, biological activity, amino containing macromolecular structure and nano-size effect. Molybdenum disulfide quantum dots (MoS₂QDs) were uniformly bonded on partially deacetylated chitin nanofibers (DEChNs) by hydrothermal reactions. The antibacterial properties of MoS₂QDs/DEChN against Escherichia coli were detected under different conditions. When the antibacterial agent was fixed at 200 μg/mL, the survival rates of bacteria were 2.77% (pH = 4), 5.58% (pH = 5) and 7.83% (pH = 6), which were lower than those in the DEChN groups. Unlike DEChN, which only had excellent antibacterial activity under acidic conditions (pH < 5), the combination of DEChN and MoS₂QDs had antibacterial activity close to neutral conditions, with a bacteriostatic rate > 90%. When TEMPO-oxidized cellulose nanofibers (TOCN) were applied for the preparation of MoS₂QDs/TOCN, they did not show obvious antibacterial ability, which proved the positive role of DEChN and its amino groups. The MoS₂QDs/DEChN assembled film could be applied to preserve meat by delaying spoilage. The current study might inspire new ideas for designing food packaging based on the prepared MoS₂QDs/DEChN films.