Multifunctional silk fibroin/PVA bio-nanocomposite films containing TEMPO-oxidized bacterial cellulose nanofibers and silver nanoparticles

Silk fibroin (SF) has been intensively studied as a biobased renewable material for biomedical and other applications. However, its relatively low mechanical properties have limited its use in the applications where an improved strength and structural integrity are desired. In this work, a bio-nanocomposite material consisting of SF/polyvinyl alcohol (PVA) as the matrix, TEMPO-oxidized bacterial cellulose nanofiber (TBC) as the reinforcement, and silver nanoparticles (AgNPs) as an antibacterial agent, was facilely synthesized. SF also functioned as a reducing agent and TBC as an immobilization template during the in-situ synthesis of AgNPs. It was found that TBC and AgNPs were homogeneously dispersed in the nanocomposites after the synthesis, which led to outstanding mechanical properties of the materials. The mechanical properties, hydrophobicity, and water vapor barrier property of the materials could be tailored by adjusting the content of TBC. Moreover, the bio-nanocomposite films exhibited strong UV shielding property, antibacterial activities and low silver leakage. These properties make the SF/PVA/AgNPs/TBC bio-nanocomposites promising materials for active food packaging and seed storage/packaging applications. Graphical abstract