Thesis (Ph.D. in Biochemistry) -- University of Colorado, 2006. / Typescript. Includes bibliographical references (leaves 118-126). Free to UCDHSC affiliates. Online version available via ProQuest Digital Dissertations;

Deoxyribonucleic acid isolated from bacteriophage lambda can infect Escherichia coli K12 in the presence of adsorbed helper phage (Kaiser and Hogness, 1960; Kaiser, 1962). The manner in which lambda DNA enters the cell and the possible role of helper phage in the penetration process is still not clear. Kinetic studies conducted in this laboratory during the initial stages of infection by lambda DNA demonstrate a requirement for helper function during the penetration of an infectious molecule. Further investigation into this problem is needed and was the major objective of this study.

Thesis--Carleton University. / Also available in electronic format on the Internet.

In this dissertation, I developed a Pd seeding method in association with electroless plating, to successfully metallize both lambda DNA and DNA origami templates on different surfaces. On mica surfaces, this method offered a fast, simple process, and the ability to obtain a relatively high yield of metallized DNA nanostructures. When using lambda DNA as the templates, I studied the effect of Pd(II) activation time on the seed height and density, and an optimal activation time between 10 and 30 min was obtained. Based on the Pd seeds formed on DNA, as well as a Pd electroless plating solution, continuous Pd nanowires that had an average diameter of ~28 nm were formed with good selectivity on lambda DNA. The selected Pd activation time was also applied to metallize "T"-shape DNA origami, and Au coated branched nanostructures with a length between 200-250 nm, and wire diameters of ~40 nm were also fabricated. In addition, I found that the addition of Mg2+ ion into the reducing agent and electroless plating solution could benefit the surface retention of Pd seeded DNA and Au plated DNA structures. This work indicated that DNA molecules were promising templates to fabricate metal nanostructures; moreover, the formation of Au metallized branched nanostructures showed progress towards nanodevice fabrication using DNA origami. Silicon surfaces were also used as the substrates for DNA metallization. More complex circular circuit DNA origami templates were used. To obtain high enough seed density, multiple Pd seeding steps were applied which showed good selectivity and the seeded DNA origami remained on the surface after seeding steps. I used distribution analysis of seed height to study the effect of seeding steps on both average height and the uniformity of the Pd seeds. Four-repeated palladium seedings were confirmed to be optimal by the AFM images, seed height distribution analysis, and Au electroless plating results. Both Au and Cu metallized circular circuit design DNA origami were successfully obtained with high yield and good selectivity. The structures were maintained well after metallization, and the average diameters of Au and Cu samples were ~32 nm and 40 nm, respectively. Electrical conductivity measurements were done on these Au and Cu samples, both of which showed ohmic behavior. This is the first work to demonstrate the conductivity of Cu metallized DNA templates. In addition, the resistivities were calculated based on the measured resistance and the size of the metallized structures. My work shows promising progress with metallized DNA and DNA origami templates. The resulting metal nanostructures may find use as conducting interconnects for nanoscale objects as well as in surface enhanced Raman scattering analysis.