Valorization of Wastepaper Through Antimicrobial Functionalization with Biogenic Silver Nanoparticles, a Sustainable Packaging Composite

Abstract

Wood pulping for paper production accounts for bulk of the tree lost, with numerous adverse effects to the environment. In this study, Eucalyptus camaldulensis leaf extract was used for silver nanoparticles synthesis. The nanoparticles were used as functional agent for the valorization of wastepaper. The nanocomposite paper was characterized for physicochemical, antibacterial and cytotoxicity. DLS and TEM revealed a spherical nano-sized particle with effective diameters of 138.6 nm and mean size of 13.11 nm, respectively while zeta potential was − 35.85 mV. Minimum inhibitory and minimum bactericidal concentrations of silver nanoparticles ranged from 0.99 to 1.99 µg/mL and 3.98–15.91 µg/mL respectively. UV–vis spectra presented a peak at 427 nm, indicating the surface plasmon resonance band of silver in the paper. SEM and EDX showed uniform distribution of silver nanoparticles, whereas EDX and ICP-OES results indicated Ag concentration of 0.1%Wt and 0.0112 µg/cm2, respectively. Antibacterial efficacy of the paper demonstrated a bactericidal effect against Bacillus cereus and Escherichia coli O157:H7 with > 3log reduction in CFU/mL after 3 h of treatment and bacteriostatic effect against Listeria monocytogenes and Staphylococcus aureus. In addition, cytotoxicity against HEK293T and Caco-2 cells revealed > 80% cell viability. Results indicate that valorization of wastepaper through functionalization with bioactive silver nanoparticles could serve as a sustainable waste management approach.