| Nanomaterials are a class of materials that have dimensions less than or equal to 100 nm. In the current research, reducing agents from plants were extracted and used, instead of sodium borohydride to reduce silver, silver-titania nanoparticles or metal organic frameworks. These systems were synthesised using hydrolysis, thermolysis (solvothermal) and characterised using UV-VIS spectroscopy and transmission or scanning electron microscopy, including X-ray diffraction to confirm crystallite size of nanoparticles (< 25 nm), morphology, porosity, crystalline phase and chemical order. The nanoparticles or nanosystems derived from a colloidal chemistry were evaluated against Gram-negative and Gram positive bacteria and other microorganism, such as Escherichia coli, or eukaryotic cells, such as human retinal pigment epithelium cells. The nanosystems were able to inhibit microbial growth (< 20 parts-per-million) or cell growth (< 50 parts-per-million). Although the mechanism of action was not investigated, using literature reports, it appears one mode of cellular deactivation is generation of reactive oxygen species, which are local to the cell wall or plasma membrane, that disrupt integrity or cellular function. The study in this thesis indicated that nanoparticles reduced with natural products are effective as functional materials with less environment contamination. It was also found that these nanoparticles can provide a feasible and environmentally-friendly synthetic approach for wide spectrum of materials. |
