Dual-crosslinked poly(vinyl alcohol)/sodium alginate/silver nanocomposite beads - A promising antimicrobial material

- Antimicrobial polymeric/metal nanocomposites can be used in active food packaging.
- PVA and SA at different ratios were used to prepare various PVA/SA/AgNPs composites.
- Dual-crosslinking of polymer/silver nanocomposites entraps silver nanoparticles.
- Escherichia coli (∼1011 CFU/ml) were killed by PVA/SA/AgNPs beads in batch culture.
- Effective killing of E. coli (∼108 CFU/ml) cells in contact with PVA/SA/AgNPs surface.

In this paper, we report the immobilization of borate-stabilized silver nanoparticles (AgNPs) as nanofillers in dual-crosslinked polymers comprised of poly(vinyl alcohol) (PVA) and sodium alginate (SA) at different ratios. Ionic-crosslinking using Ca2+ ions and physical-crosslinking by freeze-thawing were used to entrap silver nanoparticles in the prepared PVA/SA/AgNPs nanocomposite beads. These polymeric nanocomposites were characterized by UV-Vis, XRD, FE-SEM, FT-IR, TGA, and using rheological and swelling properties. The antibacterial activities of these PVA/SA/AgNPs nanocomposites were evaluated against Escherichia coli O157: H7, which causes escherichiosis through contaminated food and water. The results obtained indicated that PVA/SA/AgNPs nanocomposite formed with a ratio 10/90 of PVA to SA (formulation F5) exhibited high bactericidal activity, with entrapment of AgNPs and had excellent rheological and thermal stabilities. Due to the low cost and effectiveness of these antimicrobial nanocomposites, they have potential as an active food-packaging material for food safety and to extend shelf-life of packaged foods.