Green Synthesis of Silver Nanoparticles and Their Antibacterial Activity

Abstract

Silver nanoparticles (Ag NPs) could be prepared by effective and simple biosynthesis by using plant extracts. Water extracts from Thymus serpyllum L., Thymus vulgar-is L., and Sambucus nigra L. were used for a green synthe-sis of Ag NPs. Progress of the syntheses, the structure of Ag NPs and their antibacterial actiivity were followed by UV-Vis spectroscopy, TEM analysis and agar well diffu-sion method. UV-Vis analysis showed that the reactions performed with various plants extracts need different tem-peratures (60–90 °C) to synthesize Ag NPs. The NPs pre-pared were approx. 30 nm in size, but Ag NPs smaller than 10 nm were detected, too. Pure plant extracts without na-noparticles had no antibacterial activity. Of the Ag NPs-containing samples, only those prepared by using extract from Sambucus nigra L. showed antibacterial activity against Escherichia coli and Staphylococcus aureus. Green synthesis is a promising way to prepare NPs with biologi-cal activities.