Study of the biosynthesis of gold nanoparticles by using several saprophytic fungi

Abstract

Gold nanoparticles have wide applications, such as cancer diagnosis and treatment, drug transfer, gene transfer, and DNA and protein detection. Fungi are good options for the biosynthesis of nanoparticles, which is due to their ability to secrete a large quantity of enzymes. The purpose of the present study is to investigate the ability of several saprophytic fungi in the production of gold nanoparticles. The biomass of each fungus was first mixed with a 10 - 3 molar HAuCL4 solution and was subsequently heated for 24 h. The Change in the color of the reaction solutions from yellow to violet was symptomatic of the synthesis of gold nanoparticles. In cases where the above assessment (i.e., color change) was positive, the synthesis of gold nanoparticles was further investigated by using spectrophotometry UV–vis, X-ray diffraction and TEM electron microscope. The observation of the maximum absorption peak at a wavelength of about 540 nm in the UV–vis spectrum confirmed the production of gold nanoparticles. Moreover, the XRD analysis of the nanoparticles proved that the nanoparticles synthesized are gold nanocrystals. The TEM electron microscope technique was used to determine the shape and size distribution of the nanoparticles. Based on electromicrographs, the nanoparticles were spherical, triangular and polygonal.