Physical-chemical and antibacterial properties of green-synthesized silver nanoparticles mediated by leaf extract of Syzygium aromaticum L

Abstract

Silver nanoparticles have played an important role in many applications due to their unique properties, and green synthesis of the particles has been a popular choice as opposed to chemical and physical methods. In this study, the physical, chemical, and antibacterial properties of green synthesized silver nanoparticles mediated by leaf extract of Syzygium aromaticum L were examined. Initially, the formation of silver nanoparticles was indicated by the yellowish-brown color of the mixture of the extract and silver nitrate solution, followed by the UV-VIS spectrum of the mixture showing the surface plasmon resonance at 415 nm. The samples then were analyzed using TEM showing the particle diameters varying from 2.9 nm to 33.6 nm with the mean diameter of 20.5 ± 4.9 nm. The FTIR spectrum showed the presence of chemical bonding of organic materials on the particles indicating the involvement of the extract as reducing and capping agents in the formation of the particles. The antibacterial activity on Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli were examined using disc diffusion and spectrophotometric methods, and the results show that the silver nanoparticles inhibit the growth of S. aureus and E. coli. Results from the disc diffusion method show that the particles inhibit the growth of S. aureus and E. coli equally, while from the spectrophotometric method, the particles inhibit the growth of E. coli faster than they inhibit the growth of S. aureus.