Thesis (M.Sc.) - Cairo University - National Institute of Laser Enhanced Sciences - Department of Laser Applications

In the last decades, nanotechnology has become a key word in scientific research as well as in the public interest and it is considered as the critical research technology of the 21st century. Gold nanoparticles have been proven to be powerful tools in various nanomedicinal applications. Consequently, the study of cytotoxicity and genotoxicity of gold nanoparticles has been emerged as an important issue. In this study, we have studied the cytotoxicity (using MTT assay) and genotoxicity (using comet assay) of gold nanospheres and nanorods in human hepatocellular carcinoma cell line (HepG2). The experimental conditions such as nanoparticles preparation (surface modification), laser power, time of exposure, and concentration of the gold nanoparticles have been studied . Non-PEGylated and PEGylated Au nanospheres with Poly (ethylene glycol) methyl ether thiol (m-PEG-SH), were synthesized by citrate reduction method. Also, Au nanorods were prepared using the seed-mediated method and modified with m-PEG-SH. The prepared nanoparticles were characterized using UV-Vis. spectroscopy, dynamic light scattering (DLS) and transmission electron microscopy (TEM). The synthesized Au nanoparticles before and after the PEGylation showed very good stability for both after different types of low intensity laser exposure and in the cell culture supplementary media (RPMI). The potential cytotoxicity of the synthesized Au nanoparticles before and after PEGylation in dark conditions showed that there is no significant difference in cell viability between non-PEGylated and PEGylated Au nanospheres at the same concentration

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