Silver nanoparticles/carbon dots nanocomposite with potent antibiofilm and long-term antimicrobial activity doped into chitosan/polyvinyl alcohol film for food preservation

Exploration of robust antiseptics with antibiofilm performance and long-term antimicrobial activity is of great significance to effectively destroy foodborne pathogenic bacteria. Herein, a silver nanoparticles (Ag NPs) /carbon dots (CDs) nanocomposite (Ag@CDs) was constructed by the reaction of Ag⁺ with CDs, which has strong antibacterial ability, and mighty biofilm inhibition and destruction ability toward E. coli and S. aureus. Notably, low concentration of Ag@CDs (40.0 and 80.0 μg/mL) could ablate 86.11 % E. coli and 75.86 % S. aureus biomass of mature biofilm. To our knowledge, this is the first bactericide with powerful biofilm destruction activity. In addition, Ag@CDs exhibited long-term (30 d) antibacterial effect on the substrates of plastic, cotton, gauze, and glass. Ag@CDs was evenly dispersed into the matrix of chitosan (CS)/polyvinyl alcohol (PVA) to fabricate well-blended food packaging films. Among which, the 3 % Ag-CP film exhibited improved mechanical performance, excellent UV-Vis light blocking ability, and intensive antimicrobial activity. Despite seven days of storage, 3 % Ag-CP still could preserve the freshness and safety of the pork and shrimp, certifying it extends the storage life of packaged foods.