Thesis (M.Sc.) - Cairo University - Faculty of Pharmacy - Department of Microbiology and Immunology

An eco-friendly, non-toxic and cost-effective protocol for the synthesis of gold nanoparticles (GNPs) using submerged liquid fermentation of the fungus Pleurotus osteratus was established. Treatment of tetrachloro-auric acid (HAuCl4) solution with the free cell filtrate (FCF) of the fungus reduced the HAuCl4 ions and formed stable GNPs. These nanoparticles were characterized by Surface Plasmon Resonance (SPR) band at wavelength 550 nm for GNPs. The media components for the fungal growth were optimized using factorial design. The maximum SPR in UV-Vis spectra was recorded with a medium containing in (%); glucose (1), yeast (0.5), malt extract (0.5) and KNO3 (0.2) and incubation period 8 days, the temperature and pH were kept at 30 oC and 6, respectively. The particles were further characterized by UV/Vis spectroscopy, Transmission electron microscope (TEM), Dynamic light scattering (DLS), Fourier Transform Infrared Spectroscopy (FT-IR) and X-Ray diffraction (XRD). Exposure of fungal strain and FCF after mixing with Au+ to Gamma radiation showed 36 % increase in the SPR band intensity of the synthesized GNPs compared to un-irradiated strain and FCF irradiated before mixing with Au+. Interestingly, the synthesized GNPs exhibited antimicrobial activity against both Gram positive and Gram negative bacteria, as measured by well diffusion assay. No antifungal activity was reported. Moreover, it also showed good anticancer activity against human Breast carcinoma (T47D) cells, Prostate carcinoma (PC3) cells and Hepatocellular carcinoma (HEPG2) cells using Trypan blue exclusion and Sulfo-Rhodamine B assay

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