Thesis (M.Sc.) - Cairo University - Faculty of Science - Department of Biochemistry

The synthesis of eco-friendly nanoparticles is a needy branch of nanoscience for biomedical application. Affordable cost of synthesis and non-toxicity are main features make it more attractive and potential option for biomedical field and elsewhere. The aim of this work is to synthesize gold nanoparticles (AuNPs) using calendula officinalis flower extract as a reducing agent and investigate photocatalytic activity, antibacterial activity, antioxidant activity and anticancer activity of the bio-synthesized gold nanoparticles. The biosynthesized AuNPs were characterized by UV{u2013}Vis spectroscopy, Transmission Electron Microscopy (TEM), Zeta potential analysis, Energy dispersive X-ray spectroscopy (EDX) and Fourier transform infrared spectroscopy (FTIR). The antimicrobial efficacies towards Bacillus subtitis and Staphylococcus aureus as a gram-positive pathogenic bacterium, Escherichia coli and Pseudomonas aeruginosa as a gram-negative pathogenic bacterium were tested. Furthermore, the antioxidant capability using 2,2-diphenyl-1- picrylhydrazyl (DPPH) was measured. Also, the photo-catalytic capacity for degradation of methylene blue dye (MB) was examined. Moreover, MTT assay were carried out to investigate the cytotoxic effect of the biosynthesized AuNPs on Colorectal cell line and melanoma cell line. Based on TEM images, there are three different shapes spherical, anisotropic and flower shape with average size 13-30 nm, 50-80 nm and 50 nm for AuNPs (A), AuNPs(B) and AuNPs (C) respectively. As FT-IR findings the AuNPs and plant were linked via a hydrogen bonding. The AuNPs revealed effective photo-degradation for MB. The highest antioxidant activity was achieved by using AuNPs(C).The antimicrobial activity demonstrated the remarkable activity of AuNPs(A) over AuNPs(B) and AuNPs(C) on the four bacterial strains. Results of MTT assay revealed significant cytotoxic activity of AuNPs(A) over AuNPs(C) while AuNPs (B) showed no cytotoxic effect at all. The results of the current study spot light for using used Egyptian plant for fabricating NPs that could be involved in huge biomedical and industrial applications as food packaging and antibacterial dressings

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