زینب شیخلو - Dept. of Microbiology, Faculty of Sciences, Zanjan Branch, Islamic Azad University, Zanjan, Iran
مجتبی صلوتی - Dept. of Microbiology, Faculty of Sciences, Zanjan Branch, Islamic Azad University, Zanjan, Iran
زهره فرهمندکیا - Dept. of Environmental Health, Zanjan University of Medical Sciences, Zanjan, Iran
ساناز مهمازی - Dept. of Microbiology, Faculty of Sciences, Zanjan Branch, Islamic Azad University, Zanjan, Iran
علی عینلو - Dept. of Microbiology, Faculty of Sciences, Zanjan Branch, Islamic Azad University, Zanjan, Iran

Background and Objectives: Gold nanoparticles have found many applications in cancer diagnosis and therapy, drug and gene delivery and DNA and protein characterizations. Fungi are extremely good candidates in the synthesis of metal nanoparticles because of their ability to secrete large amounts of enzymes. The aim of this study was biosynthesis of gold nanoparticles by a fungus. Materials and Methods: The sampling was performed from the Ahar copper mine. The biomasses of isolated fungi were incubated with HAuCl۴ solution in a shaker-incubator for ۷۲ hr, and the strains that were able to produce gold nanoparticles were identified. The production of gold nanoparticles was studied with UV-vis spectroscopy, X-ray diffraction (XRD) and transmission electron microscopy (TEM). Results: Among the eight types of fungi that were isolated from the Ahar copper mine, only Rhizopus oryza was able to synthesize gold nanoparticles. The synthesis of gold nanoparticles was confirmed by observing the characteristic peak at ۵۴۰ nm using UV-vis spectroscopy. The XRD analysis confirmed that the produced gold nanoparticles are in the form of nanocrystaline. Transmission electron microscopy images showed that Rhizopus oryza produces gold nanoparticles with good monodispersity in spherical and trigonal shapes both intra- and extracellularly. Conclusion: Fungus Rhizopus oryza is able to produce gold nanoparticles in the size range of ۱۰-۷۰ nm. This biologic method has the potential to replace chemical and physical methods currently used for gold nanoparticles production.

Keywords: Gold nanoparticles, Biosynthesized, Rhizopus oryza