Synthesis and characterisation of silver nanoparticles from Rheum Ribes roots extract

Nano-particles, ultrafine particles [1], are particles between 1 and 100 nanometres in size [2]. Nano-particles show interesting properties differ than normal size. Their applications in many areas of science are growing. Accordingly, the field of nano-technology is more interest for researchers [3]. Synthesis and characterization of gold and silver nano-particles are the most studied in nano-technology [4]. Nowadays, developing of plant-mediated green synthesis is demanded. In this study, silver nano-particles (Ag-NPs) were synthesized from silver nitrate by Rheum ribes roots extract as reducing and stabilizer agents. The silver nanoparticles (Ag-NPs) were prepared using silver nitrate as silver precursor and the aqueous stem extracts of Rheum ribes as reducing agent and stabilizer. First of all the aqueous extract of Rheum ribes roots was extracted by boiling method. Next several concentrations (0.25, 0.5, 1 and 2 mM) of silver nitrate were added to extract for biosynthesis of NPs at several temperatures (10, 25 and 40˚C). Finally, changing the color of extract was occurred and indicated the end of biosynthesis. Plant-mediated synthesized Ag-NPs were confirmed by absorption peak at 420 nm. Comparison of the obtained UV spectra showed that biosynthesis at 40˚C with 2 mM silver nitrate was optimum condition. After that, The biosynthesised nanoparticles were isolated by ultracentrifuge and introduced to DLS and SEM for size characterization.