Microbial biosynthesis of nontoxic gold nanoparticles

We study the extracellular biosynthesis of gold nanoparticles (GNPs) using the fungal species Aspergilius foetidus. The formation of GNPs were initially monitored by visual observation and then characterized with the help of various characterization techniques. X-ray diffraction (XRD) results revealed distinctive formation of face centered cubic crystalline GNPs. From field emission scanning electron microscopy (FESEM) the morphology of the nanoparticles were found to be roughly spherical and within the size range of 30-50 nm. The spherical and polydispersed GNPs in the range of 10-40 nm were observed by transmission electron microscopy (TEM) analysis. It was established that alkaline pH, 1 mM gold salt concentration and 75 degrees C temperature were the respective optimum parameter for biosynthesis of GNPs. Cell cytotoxicity of GNP was compared with that of normal gold salt solution on A549 cell. The A549 cell growth in presence of GNPs was found to be comparatively less toxic than the gold ion. (C) 2015 Elsevier B.V. All rights reserved.