o Azizian Shermeh - Department of Chemistry, University of Sistan and Baluchestan, Zahedan, Iran
m Valizadeh - Department of Medicinal Plants, High Educational Complex of Saravan,, Saravan, Iran
j Valizadeh - Department of Biology, University of Sistan and Baluchestan, Zahedan, Iran
m Taherizadeh - Department of Chemistry, University of Sistan and Baluchestan, Zahedan, Iran

Introduction: The field of nanotechnology is the most active area of research in modern materials science. Though there are many chemical as well as physical methods, green synthesis of nanomaterial is the most emerging method of synthesis. We report the biosynthesis, optimization and characterization of antibacterial silver nanoparticles using medicinal herb, Pulicaria undulata L.Material and Methods: 1 g of powdered sample was added to 100 ml of distilled water for 30 min at 50◦c. After filtration 2 ml of extract was added to 4 ml of AgNO3 solution (1mM). Influence of extract, metal concentrations, contact time and pH of reaction were evaluated to find their effect on uniform shape and size of nanoparticles. All parameters were optimized using UV-Vis spectrophotometry. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were also employed to find characterization of the nanoparticles. Finally, the antimicrobial activity of AgNPs were evaluated against pathogenic bacteria and fungi.Results: The results showed that, the best optimal conditions for the synthesis of nanoparticles are: pH= 8, 3ml of extract, 4 ml of AgNO3 solution with concentration (4 mM) and the time of reaction is 10 min. Ag NPs showed maximum absorbance at 412 nm. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were also employed to find characterization of the nanoparticles. It was found that biosynthesized nanoparticles have a uniform spherical shape with a size between 6-10 nm. Also the AgNPs that synthesized by this method showed high antibacterial activities.Conclusion: We believe that plants have great potential to synthesis of metal nanoparticles and the nanoparticles have great potential for applications in catalysis, biomedical, and pharmaceutical industries.

Pulicaria undulate L, biosynthesis, silver nanoparticles, antibacterial activity