京都大学 / 新制・課程博士 / 博士(工学) / 甲第23920号 / 工博第5007号 / 新制||工||1781(附属図書館) / 京都大学大学院工学研究科高分子化学専攻 / (主査)教授 秋吉 一成, 教授 大内 誠, 教授 大塚 浩二 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

This thesis outlines a study of the physical changes that hybridisation imposes on single-stranded DNA (ssDNA) immobilised by one end to a substrate, and of how such physical changes can be exploited to detect specific sequences of DNA in a target solution. The system studied was composed of a mixed monolayer of 20mer ssDNA with C6 alkanethiolate modifications on their 3??? ends and short-chain hydroxyterminated alkanethiolates, on a gold substrate. It was prepared using the self-assembly properties of alkanethiols on gold. Atomic force microscopy images showed that the end-immobilised ssDNA is flexible enough to lie over the diluent hydroxy-terminated self-assembled monolayer (SAM). Hybridisation was shown to cause the DNA to become more rigid and stand up off the substrate due to an increase in persistence length. Such physical changes of the DNA upon hybridisation were significant enough to be exploited in the development of a DNA recognition interface. The recognition interface was designed with the view of keeping it both simple to make and simple to use, and was coupled with electrochemical transduction. A label-free recognition interface was developed that relied on the oxidation of the sulfur head group of the alkanethiolate SAM to detect hybridisation (firstly air oxidation and then electrochemical oxidation). It produced a positive signal upon hybridisation with complementary target DNA. Improvements in the reliability and robustness of the recognition interface were made using a labelled approach. The labelled version employed electroactive molecules as labels on the 5??? ends of the probe DNA strands. Two labels were investigated ??? anthraquinone and ferrocene. The flexibility of the ssDNA ensured that the redox labels were able to directly access the underlying gold electrode. Hybridisation was expected to remove the labels from the electrode due to an increase in the DNA???s persistence length, and thus perturb the electrochemical signal. The use of ferrocene as a label provided a ???proof-of-concept??? for the system. The labelled recognition interface provides a foundation for the future development of a simple, reliable, and selective DNA hybridisation biosensor.

The adsorbed layer morphology of a series of surfactants under different conditions has been examined primarily using atomic force microscopy (AFM). The morphologies of single and double chained quaternary ammonium surfactants adsorbed to mica have been characterised using AFM at concentrations below the cmc. Mixing these different types of surfactants systematically allowed a detailed examination of the change in adsorbed film curvature from the least curved bilayers through to most curved globules. From this study a novel mesh structure was discovered at curvatures intermediate to bilayers and rods. A mesh was again observed in studies examining the morphology change of adsorbed nonionic surfactant films on silica with variation in temperature. Other surfactant mixtures were also examined including grafting non-adsorbing nonionic surfactants and diblock copolymers into quaternary ammonium surfactant films of different morphologies.

Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (p. 133-150).

Thesis (M.M.S.E.)--University of Delaware, 2008 / Principal faculty advisor: Robert L. Opila, Dept. of Materials Science & Engineering Includes bibliographical references.

Thesis (Ph. D. in Chemical Engineering)--Vanderbilt University, May 2006. / Title from title screen. Includes bibliographical references.

Thesis (Ph. D.)--University of Oregon, 2008. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 164-192). Also available online in Scholars' Bank; and in ProQuest, free to University of Oregon users.

Thesis (Ph. D.)--State University of New York at Binghamton, Department of Chemistry, 2008. / Includes bibliographical references.

Thesis (Ph.D.)--Chemistry and Biochemistry, Georgia Institute of Technology, 2009. / Committee Chair: Marcus Weck; Committee Member: Bunz, Uwe; Committee Member: Collard, David; Committee Member: Jones, Christopher; Committee Member: Payne, Christine

Thesis (Ph. D.)--Chemistry and Biochemistry, Georgia Institute of Technology, 2005. / Weck, Marcus, Committee Chair ; Jones, Christopher, Committee Member ; Collard, David, Committee Member ; Liotta, Charles, Committee Member ; Bunz, Uwe, Committee Member. Includes bibliographical references.