Journal of Nanomedicine & Nanotechnology

Biosynthesis, optimisation and characterisation of gold nanoparticles using fungal extracts

7^th World Nano Conference

June 20-21, 2016 Cape Town, South Africa

Ruqsar Bibi Ismail

University of KwaZulu-Natal, Durban

Posters & Accepted Abstracts: J Nanomed Nanotechnol

Abstract:

The development of techniques for the synthesis of nanoparticles of well-defined size, shape and composition is a challenge and an important area of research in nanotechnology. Many microorganisms have the ability to produce inorganic nanostructures and metal nanoparticles with properties similar to chemically synthesized materials and are a good alternative approach to chemical synthesis. In the present study, extracellular synthesis of gold nanoparticles (AuNPs) in the presence of fungal extracts has been successfully demonstrated to manipulate the size and shape of gold nanoparticles by alteration of key growth parameters (Temperature, pH, incubation period, and sodium citrate concentrations) and reaction conditions (Supernatant: HAuCl4). Production of nanoparticles was confirmed by the colour change from yellow to violet-blue after ~72h of reaction. The synthesis of the AuNPs was monitored by UV-visible spectroscopy which showed an absorbance peak at ~530 nm which was specific for gold nanoparticles. The particles thereby attained were characterized by Transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier transform infrared (FTIR) and energy dispersive X-ray (EDX) analysis. TEM images revealed that the nanoparticles were spherical, triangular, rod-shaped, polygonal and irregularly shaped with indefinite morphology in the range of 3-460 nm in size. The most promising results were obtained when the fungus was grown at pH 3, 40º C and the best parameters for the synthesis of gold nanoparticles were pH 3, 32 ºC, 40h, 5mM sodium citrate concentrations and ratio of 1:100. The GNPSs were monodisperse, spherical and found to be 3-53 nm in size. FTIR absorption spectrum showed the presence of bonds due to O-H stretching (around ~3,430 cm -1). This peak indicates the presence of proteins and other organic residues, which might have been produced extracellularly during the growth of the fungus. An elemental composition analysis employing EDX showed the presence of a strong signal from gold atoms. However, there were other EDX peaks for C, O, Cr, Cu and Fe, suggesting that they were mixed precipitates from the fungal extracts and the copper disks. This study represents an important advancement in the use of of fungal enzymes for the biosynthesis of highly stable gold nanoparticles by a greener approach and this proposed mechanistic principal might serve as a set strategy for the synthesis of nanostructures with desired morphology and can be amenable for large scale commercial production and technical applications.

Biography :

Ruqsar Bibi Ismail obtained her Bachelor of Science with Majors in Genetics and Microbiology from the University of KwaZulu-Natal in 2013 and in 2014 pursued further a Bsc (Honours) degree in Microbiology and won best student presentation at the 27th annual South African Society for Microbiology-KZN Symposium. Ms Ismail is currently a Masters student in the School of Life Sciences at the University of KwaZulu-Natal (Westville) and has shown interest in green biotechnology and sustainable development.

Email: 211522494@stu.ukzn.ac.za