Thèse doctorat : Matériaux : Ecully, Ecole centrale de Lyon : 2007. / Titre provenant de l'écran-titre. 139 références.

Thesis (Ph. D.) in Physics--University of Maine, 2001. / Includes vita. Includes bibliographical references (leaves 122-128).

Thesis (Ph. D.)--University of Hong Kong, 2002. / Includes bibliographical references (leaves 128-133).

Metal oxides are important materials that are being developed for use in research and health-related applications. In particular, TiO2 and ZnO nanomaterials for applications in antibacterial coatings, pollutant purification, and photovoltaic devices have been extensively studied. The photocatalytic performances are highly dependent on morphology and crystal structure. However, there are few studies are comparing pollutant purification and antibacterial behavior of different TiO2 nanostructures and less studies of antibacterial activity related to fundamental properties of ZnO. In this study, the details of proposed mechanism and principle of antibacterial mechanisms of metal oxide nanostructures has been examined. Different TiO2 nanostructures (nanotubes, nanorods) have been successfully synthesized and their photocatalytic properties have been studied. In addition, studies of basic properties of commercial ZnO nanoparticles related to antibacterial activity have been performed. / published_or_final_version / Physics / Master / Master of Philosophy

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M13 filamentous bacteriophage has been used as a biotemplate for the nucle- ation of materials. Phage is an ideal and diverse scaffold with its large aspect ratio and ability to display biomolecules to bind a range of targets. To form more complex patterned materials, interactions between the phage must be specific and reliable. We develop a phage labeling method using sortase enzymes to create multi-phage nanostructures. We exploit two sortases and functionalize the N-termini of the pIII, pIX, and pVIII proteins with small and large moieties. For the pVIII, we show a 100 fold improvement in display of GFP molecules on the phage surface. Taking advantage of orthogonal sortases, we simultaneously label two capsid proteins on a single phage particle. Using these N-terminal labeling techniques, we demonstrate fluorescent staining of cells and construct a lampbrush phage structure linking the pIII of one phage to the pVIII of another using a biotin-streptavidin linkage. To further expand our labeling repertoire, C-terminal sortase labeling of phage was pursued. To achieve this goal, we transfer a loop structure from cholera toxin to pIII and label it with a fluorophore and a multi-domain protein. With this archi- tecture, we form end-to-end dimers using sortase to conjugate the loop structure to phage containing the nucleophile motif. Lastly, we investigate DNA hybridization as a method for crosslinking phage. Using sortase, we label the pVIII on two sets of phage: one with ssDNA and the other with a complementary DNA oligonucleotide. We anneal these phages together and observe phage networks that are dispersed by heat and reform upon cooling.

Nanostructures, molecular assemblies at the nanometer scale, are currently influencing diagnostics, imaging, and therapeutics. Many nanostructures are built using supramolecular chemistry principles, where hydrogen bonding between simple building blocks causes the formation of specific morphologies. Here we hypothesize that a six stranded DNA nanotube can be generated by tethering triaminopyrimidine and cyanuric acid building blocks as bases on the natural DNA backbone. We also hypothesize that cyanuric acid, a secondary oxidation product of guanine, will form complex architectures with adenine, its natural hydrogen bond complement. To test these hypotheses, we used multi-step synthetic strategies to generate DNA strands of cyanuric acid and triaminopyrimidine. The synthesis of the cyanuric acid DNA strand is complete and preliminary self-assembly studies with adenine DNA strands have been performed. The synthesis of the triaminopyrimidine DNA strand is ongoing. This thesis provides the groundwork for incorporating supramolecular building blocks into DNA to generate complex DNA architectures.

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Thesis (Ph.D.) in Chemical Engineering--University of Maine, 2007. / Includes vita. Includes bibliographical references (leaves 92-107).

Thesis (Ph.D.)--University of Delaware, 2008. / Principal faculty advisors: Chin-Pao Huang, Dept. of Civil and Environmental Engineering, and S. Ismat Shah, Dept. of Materials Science Includes bibliographical references.