Green Synthesis of Fe₃O₄/ZnO Nanocomposite Using Vernonia amygdalina Leaf Extract for Antibacterial Applications

Abstract

Green synthesized ZnO/Fe3O4 composite nanostructures have emerged as promising materials due to their unique combination of magnetic and semiconducting properties. These properties make them suitable for the application of antibacterial activity. Thus, the study was focused on the synthesis, characterization, and antibacterial properties of ZnO nanoparticles (NPs), Fe3O4 NPs, and their resulting Fe3O4@ZnO nanocomposite. The synthesized materials were characterized by using the modern instrumental techniques including x-ray diffraction (XRD), Fourier transforms infrared (FT-IR), and scanning electron microscope (SEM). The crystalline structure of the materials, with ZnO displaying a hexagonal wurtzite structure and Fe3O4 exhibiting an inverse spinel structure confirmed by X-ray diffraction (XRD). The nanocomposite presented combined peaks from both ZnO and Fe3O4, indicating the coexistence of both phases and a smaller crystallite size compared to Fe3O4 NPs. Followed, the characterized materials was tested for the antibacterial performance against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Streptococcus pyogenes. Findings confirmed that the Fe3O4@ZnO nanocomposite sowed superior antibacterial activity compared to individual NPs, as evidenced by larger inhibition zones in diffusion experiments. The enhanced antibacterial activity is attributed to the synergistic effects of ZnO and Fe3O4, including increased Reactive Oxygen Species (ROS) generation and improved stability. Disk diffusion assays assured the greater effectiveness of the nanocomposite against a range of bacterial strains. The improved performance of the nanocomposite is likely due to the combined antimicrobial mechanisms of Fe3O4@ZnO nanocomposites. These findings highlight the potential of the Fe3O4@ZnO nanocomposite as a promising candidate for diverse antibacterial applications