Green Synthesis and Characterization of Ag/Zn Bimetallic Nanoparticles Using Garlic (Allium Sativum L) Plant Extracts for Antibacterial Applications

Abstract

In this study, Ag/Zn bimetallic nanoparticles (BMNPs) and silver nanoparticles (Ag NPs) were synthesized via the green synthetic method by using the extracts of Allium Sativum L plant. The antibacterial activities of Ag/Zn bimetallic and Ag NPs were investigated against selected bacterial strains. The synthesized NPs were characterized by using techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform Infra-red (FTIR) and UV-vis spectroscopy. The XRD results confirmed cubic crystal structure for the Ag/Zn BMNPs and the average crystallite size was found to be 17.47 nm. Ag NPs were also found to exhibit cubic phase structure and an average crystallite size of 9.31 nm. UV-vis spectra of Ag NPs and Ag/Zn BMNPs showed absorbance maxima at 402 nm and 360 nm, respectively. The SEM images showed a spherical shape for Ag NPs and Ag/Zn BMNPs. The antibacterial activities of the synthesized nanoparticles were tested against gram-negative bacterial strains (Escherichia coli and Pseudomonas aeruginosa) and gram-positive bacterial strains (Streptococcus pyogenes and Staphylococcus aureus) using the agar-well diffusion method. The maximum zones of inhibition of 19 mm and 16.5 mm were recorded for Ag NPs and Ag/Zn BMNPs against P. aeruginosa, respectively. In addition, the antibacterial effect was found to increase with an increase in the concentration of both Ag and Ag/Zn NPs. The results substantiated that the antibacterial activity of Ag NPs was superior to that of Ag/Zn BMNPs for both gram-negative and gram-positive bacterial strains.