LAUSR

Abstract Bio-nanotechnology is a rapidly growing scientific field of producing Nano sized particles by using biological systems. In this study the biosynthesis of silver nanoparticles (Ag NPs) using leaf extract of Satureja hortensis treated with different concentration of NaCl (0, 50, 100 and 150 μM) was reported. In addition, the nanoparticles were assessed against two gram-positive and one gram-negative bacteria. The biosynthesized Ag NPs were characterized using FESEM, XRD, UV/vis spectroscopy and related to the size, shape and morphology of the nanoparticles as revealed by FESEM. FTIR spectrum indicated various functional groups effective on Ag NPs biosynthesis. In each treatment, the plant extract showed color change from yellow to brownish-red after Ag NPs biosynthesis. The surface Plasmon resonance found at 450 nm confirmed the formation of Ag NPs. The highest rate of Ag NPs biosynthesis was related to 150 μM treatment. FESEM images revealed relatively spherical shape ranged from 2.9 to 3.4 nm. FTIR results expounded the functional groups of plant extract responsible for the bio-reduction of silver ions and their interaction between them. Ag NPs biosynthesis by 150 μM treatment showed the smallest size (2.9 nm) and thus the most antibacterial activity especially against Bacillus subtilis. Our results revealed that aromatic bicyclic monoterpenes have the most effective role in the biosynthesis process in 150 μM treatment. To the best of our knowledge no similar study has been reported.