Steroidal saponin based extracellular biosynthesis of AgNPs

Plant based synthesis of metallic nanoparticles is an increasing commercial demand due to its wide application in various areas such as electronics, catalysis, chemistry, energy, cosmetics and medicine. Silver nanoparticles were synthesized by adding an extract of Dioscorea deltoidea in AgNO3 solution and characterized by using UV-visible spectroscopy and, transmission electron microscopy (TEM). The main constituent of extract, i.e., Diosgenin, interacts with AgNO3 which showed gradual change in the color of the reaction mixture from colorless to yellowish brown with intensity increasing during the period of incubation. Hence, the extract acts as a reducing and capping agent. The cetyltrimethylammonium bromide (CTAB) markedly enhanced the reaction path and changed the morphology (size, shape and distribution). The diameter of the AgNPs ranged from 11.2 nm to 103.4 nm.