Biosynthesis of Antibacterial Silver Nanoparticles using Astragalus verus Olivier

In this work, a green method was introduced for preparing silver nanoparticles (Ag NPs) using gum tragacanth extracted from Astragalus verus Olivier. The absence of a chemical reducing agent that may be toxic is an advantage of this method. The Ag NPs were prepared in different tragacanth concentrations, pH values, and temperatures. XRD, FT-IR, and UV–vis spectroscopy analyses confirmed the structure of the synthesised Ag NPs. TEM and FESEM images showed that the prepared Ag NPs have spherical shapes. The FESEM images determined that a pH of 10 and a synthesis temperature of 50°C would be the optimal condition for preparing Ag NPs in this method. The change in concentration of tragacanth does not have much effect on the quality of Ag NPs. Obtained data from DLS revealed that the average diameter of Ag NPs is about 40 nm. The antibacterial activity of the prepared nanoparticles was evaluated against both Gram-positive and Gram-negative bacterial species. The results of the antibacterial tests showed that the prepared Ag NPs possess a desirable antibacterial activity.