Nanoparticles are synthesized using different physical and chemical methods. However, the development of an eco-friendly approach for the synthesis of nanoparticles is of critical importance to nanotechnology. Types of fungi which secrete a high amount of proteins are ideal candidates for the eco-friendly synthesis of nanoparticles. In this research, the extracellular biosynthesis of silver nanoparticles was implemented, using Botrytis cinerea. UV-vis spectroscopy illustrated a sharp peak at 420 nm, demonstrating the presence of silver nanoparticles in the fungal cell filtrate. Further analysis was accomplished through TEM and FTIR. Silver nanoparticles were spherical and 5.1-13.95 nm in diameter with an average size of 8.55 nm. NPs were stable three months after their formation, which is, quite likely, due to their capping with proteins which were secreted by the fungus
