Improvement in antibacterial and functional properties of mussel-inspired cellulose nanofibrils/gelatin nanocomposites incorporated with graphene oxide for active packaging

Inspired by the natural mussel chemical engineering, we proposed a novel and biomimetic strategy for the fabrication of strong integrated gelatin/cellulose nanofibrils (CNF) nanocomposite materials reinforced with functional graphene oxide (GO) nanohybrids. GO nanosheets were chemically reduced and dip-coated to yield poly(dopamine) (PDA)-functionalized GO (PGO) via self-polymerization of catechol-containing dopamine. Furthermore, Ag nanoparticles (NPs) were further prepared and immobilized by the catechol groups of the functional PDA layers through in-situ reduction and strong catechol-metal interaction. The fracture surface morphology clearly revealed that the interfacial adhesion of gelatin-based nanocomposite was remarkably improved via the synergistic effect and multiple cross-linking interactions of the CNF-PGO nanohybrids and Ag NPs. The tensile strength and toughness of the nanocomposite film were simultaneously increased to 35.99 MPa and 13.49 MJ/m3, respectively. The water vapor permeability of the nanocomposite was remarkably reduced by 51.60%. The nanocomposite film showed strong antibacterial activity against both S. aureus and E. coli pathogenic bacteria. In addition, the film also exhibited significant improvement in the water resistance, UV-shielding capacity, and thermal stability. Hence, the bio-inspired strategy for constructing functional PGO nanohybrids in renewable natural gelatin/CNF nanocomposites provides a promising approach to the fabrication of active packaging materials for a wide range of industrial applications.