Aloe vera-synthesized Ag nanoparticles loaded on PVA/chitosan as biodegradable and antibacterial film for food storage

We have developed a novel, eco-friendly, and active food packaging film by incorporating green-synthesized silver nanoparticles (AgNPs) into polyvinyl alcohol (PVA) and chitosan matrices. The AgNPs were in situ and green synthesized in high-yield by using Aloe vera extract as a reducing agent and chitosan as a stabilizing agent at high temperature. The obtained AgNPs exhibit quasi-spherical shapes and tunable size in the range 20 ∼ 30 nm by controlling the content of AgNO₃ precursor in the growth solution. The in situ synthesis enables the homogeneous distribution of AgNPs throughout the films and eliminates the need for purification. The effect of the loaded amounts of Aloe vera-synthesized AgNPs on the film characteristics was investigated. The results show that the obtained AgNPs-loaded films exhibit excellent mechanical properties (tensile strength of 36.7 MPa and elongation at break of 213.9%) and superior bacterial killing and inhibition effects against E. coli. Moreover, the incorporation of green-synthesized AgNPs into the polymeric films also results in a significant improvement in the contact angles formed between the film surface and glycerol droplets, enhanced thermal stability, and a reduction in water swelling and water solubility. All these results highlight the great potential of these biodegradable and antibacterial membranes as an alternative to petroleum-based plastics in food packaging and preservation.