Thesis (M.Sc.) - Cairo University - National Institute of Laser Enhanced Science - Department of Laser Application Environmental Metrology, Photochemistry and Agriculture

Chitosan is derivative of chitin, which, considered as the second most abundant natural polysaccharide on the planet. Due to its properties such as antimicrobial activity, biocompatibility, non toxicity, chitosan has a wide range of applications especially, biomedical applications. In this study, chitosan was prepared in two forms, general molecular form nano form. High quality chitosan of low molecular weight and high degree of deacetylation had been extracted from shrimp shells. The parameters were fixed at 4 and CS: TPP (chitosan: tripolyphosphate) ratio was kept at 3 : 1 to prepare chitosan nanoparticles with 25.37nm size and 27.8mV charge density. The chitosan nanoparticles were used as a host material for synthesis of metallic nanoparticles (gold and silver) to form photo stable bio nanocomposites. This bionanocomposite was designed to improve the antibacterial activity for both chitosan nanoparticles and metallic nanoparticles which can be used safely in several antibacterial applications. The results revealed that the antibacterial activities were increased in the following order chitosan-silver nanocomposite > chitosan nanoparticles > chitosan gold nanocomposite >molecular chitosan

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