Gold Nanoparticles, ZnO Nanostructures: Applications In The Cancer Treatment And Biosensing

Nanotechnology is a typical multidisciplinary realm including physics, chemistry, electronics and biology. The combination of nanotechnology and biomedicine which is termed as nanobiomedicine has received much attention recently. In this field, researchers dedicate to the research on the detection and treatment of major diseases such as cancer, diabetes or cardiopathy with nanomaterials. Although impressive progress has been achieved, there still exists a significant challenge to design and synthesize functionalized nanomaterials with good biocompatibility. In this dissertation, we focus on the synthesis of functionalized 0D and 1D nanomaterials and explore their applications in the cancer treatments and sensing of biomolecules.In chapter 1, we first summarized the synthesis strategies on the nanomaterials briefly. Then we introduced the typical applications of the nanomaterials in the biological fields. Lastly, we discussed the main contents and significance of the dissertation.In chapter 2, we successfully synthesized gold nanoparticles (GNPs) with various types of chemical surface features. The cell uptake and radiation cytotoxicity enhancement of GNPs in the breast cancer have been well investigated. It's shown that the size, concentration and surface modification of GNPs can affect the cell uptake. As for the citrate sodium modified GNPs, 98nm diameter GNPs are mostly uptaken by the breast cancer cells and the number of the GNPs in the cells increases linearly with their concentration. Selective bond with the cell membrane or localized to the cytoplasm was also achieved with cysteamine (AET-GNPs) or thioglucose (Glu-GNPs) modified GNPs, respectively. Radiation experiments demonstrated that both of AET-GNPs and Glu-GNPs could increase the cytotoxicity of 200kVp X-ray to the cancer cells, but not to the normal cells. By comparison with difference type of radiation (60Co, 137Csγ-ray), we suggest that the photoelectric effect might be a major mechanism for GNP-induced increase of cytotoxicity by the interaction between low-energy X-ray and GNPs.In chapter 3, a glucose biosensor was fabricated with immobilization of glucose oxidase onto the ZnO nanotube arrays. The ZnO nanotube arrays were prepared by chemical etching of ZnO nanorods that were electrochemically deposited on the Au surface. Factors affecting the morphology of ZnO nanoarrays such as reaction time, temperature and applied voltage were studied. The glucose biosensor was fabricated via cross-linking method. The biosensor showed a fast and sensitive response to the detection of glucose. It has a wide linear range from 50μM to 12mM with 3s response time. The sensitivity of the biosensor is found to be 21.7μA/mM·cm2. Moreover, its experimental detection limit is 1μM (signal to noise ration of 3) and the apparent Michaelis-Menten constant is calculated to be 19mM. The biosensor also exhibited good anti-interference ability and long-term stability. All these results demonstrated that ZnO nanotube can provide a promising material for the biosensor designs and other biological applications.In chapter 4, a nonenzymatic H₂O₂ sensor was constructed based on palladium nanoparticles decorated ZnO nanorods (Pd-ZnONR) fabricated by electrodeposition method. The factors affecting the Pd-ZnONR morphology such as electrodeposition time, initial PdCl2 concentration were qualitatively assessed. The Pd-ZnONR showed high electrocatalytic ability to the electro-reduction of hydrogen peroxide (H₂O₂). The fabricated nonenzymatic H₂O₂ sensor had a quite wide linear range from 2.5μM to 23mM, low experimental detection limit of 2.5μM and large sensitivity of 0.405mA/mM·cm2. The sensor also had good anti-interference ability and long-term stability. The results demonstrate that the Pd-ZnONR is a promising material for nonenzymatic H₂O₂ sensing.In chapter 5, we gave a prospect on the topics discussed in this dissertation.