Bioinspired interface engineering of gelatin/cellulose nanofibrils nanocomposites with high mechanical performance and antibacterial properties for active packaging

Developing an integrated biopolymer material combining favorable mechanical properties and antibacterial activity remains a great challenge. In this study, we designed a tough, hydrophobic, and antibacterial gelatin-based nanocomposites by constructing synergistic multiple coordination bonds between dopamine (DA)-grafted cellulose nanofibrils (DCNF) and montmorillonite (MMT) in a covalent polymer network. Silver nanoparticles (AgNPs) were prepared and anchored to the gelatin chains and MMT-DCNF nanohybrids using in-situ reduction and the strong catechol-metal interactions of poly(dopamine). As a result of the efficient energy dissipation ascribed to the multiple cross-linked network structure, the tensile stress and toughness of the hybrid films were simultaneously improved by 400.9% and 991.5%, respectively. The hybrid films displayed strong antibacterial activity against Staphylococcus aureus (gram-positive) and Escherichia coli (gram-negative) pathogenic bacteria because of the incorporation of AgNPs into the gelatin matrix. Compared with traditional active packaging, this gelatin-based nanocomposite film is renewable and biodegradable, it exhibited superior mechanical properties, UV-shielding capacity, water resistance, thermal stability, and antibacterial activity, which are essential characteristics for commercial applications in complex environments. This work provides a novel and facile strategy for the design of integrated gelatin-based nanocomposites with promising functional properties for application as active packaging materials.