Antibiofilm, antibacterial and antioxidant activity of biofabricated bimetallic (Ag-ZnO) nanoparticles from Elephantopus scaber L

Developing the most reliable and eco-friendly techniques for nanoparticle synthesis is an emerging step in green nanotechnology. Intending to avoid the potential risks of harmful substances for a safe environment, research on environmentally friendly methods of generating metal/metal oxide nanoparticles (NP) is increasing. In this study, the aqueous leaf extract of Elephantopus scaber was used to create bimetallic nanoparticles (Ag-ZnO), and the synthesized Ag-ZnO NPs were characterized for their physical and chemical properties. Different spectroscopic and microscopic methods, including UV–visible spectroscopy, FTIR, scanning electron microscopy (SEM), EDX, and XRD, were used to characterize the synthesized Ag-ZnO NPs. SEM revealed the nanoparticles’ irregular shape, and FTIR demonstrated that secondary metabolites served as capping and stabilising agents during the production of the particles. The antioxidant activity of biosynthesised bimetallic nanoparticles was determined using DPPH, hydroxyl and reducing power assays. The E. scaber-mediated Ag-ZnO NPs were tested for their antibiofilm, antibacterial, and antioxidant effects and are reported. The biosynthesised nanoparticles showed significant antioxidant activity of 62% at 500 µg/ml concentration. The results of antibacterial activity showed that MIC of biosynthesised Ag-ZnO NPs was 0.125 μg/ml against Staphylococcus aureus and Bacillus subtilis. The results of studying the antibiofilm activity of Ag-ZnO NPs showed that it was concentration-dependent. Results obtained from the present study indicate that the biosynthesised Ag-ZnO NPs using E. scaber leaf extract are eco-friendly and can be used as a good antibacterial, antibiofilm and antioxidant agent.