Antibacterial and Antifungal Efficacy of Silver Nanoparticles Biosynthesized Using Leaf Extract of Thymus algeriensis

The present study reports a cost effective and environment friendly technique for the preparation of silver nanoparticles (AgNPs) using Thymus algeriensis leaf extract as reducing and capping agent. The effects of reactants ratio, contact time, pH and temperature on the synthesis of the Ag nanoparticles were investigated. It was found that the rate of formation of silver nanoparticles enhanced with time at high temperature and alkaline pH. The biogenic AgNPs were characterized by UV-Visible spectrophotometer, showing a typical surface Plasmon resonance at about 430 nm which is specific to AgNPs. XRD and SEM-EDX results reveal that the synthesized nanoparticles have a face centered cubic structure (fcc). TEM images clearly show that the biosynthesized nanoparticles are mostly spherical with an average particle sizes between 10 and 20 nm. Fourier transform infrared spectroscopy (FTIR) was used to identify the biomolecules and capping reagents in the T. algeriensis leaf extract that may be responsible for the reduction of silver ions and the stability of the bioreduced nanoparticles. The AgNPs as potential anti-bacterial and anti-fungal agents have been studied on gram negative (P. aeruginos and E. coli), gram positive (B. cereus, and S. aureus) pathogenic clinical bacteria and pathogenic fungi (Candida albicans). The results showed that the biologically synthesized AgNPs exhibit interesting anti-bacterial and anti-fungal activity with those clinical pathogens.