DNA photocleaving reagents are a unique class of molecules that display the
ability to cleave DNA, causing strand breaks, upon exposure to an irradiation source. In
terms of biological applications, achieving excitation through a two-photon absorption
event provides for unique benefits that can be useful in such applications as
photodynamic therapy and cell viability studies. Thus, this thesis pertains to the study of a
class of photocleaving reagents that have been shown to become excited through a twophoton
process during irradiation with a pulsed femtosecond laser at 775 nm.
N-(Alkoxy)pyridinethiones were selected as possible oxygen-based radical
generators upon irradiation at two-photon wavelengths. Experiments were carried out
with pBR 322 plasmid DNA to determine if these N-(alkoxy)pyridinethiones could cause
strand cleavage and if so how efficient they are in doing so. Several compounds were
found to be effective DNA strand cleavers when irradiated at two-photon wavelengths,
displaying the utility of two-photon excitation in biological studies. Rationale is
suggested for the observed variation in cleaving efficiency based on inherent properties of
the generated radicals.
A second study was done to measure the two-photon cross section of the
compound N-(anthracenoyloxy)pyridinethione. The two-photon cross section was found
by measuring the fraction of substrate remaining after specific periods of femtosecond
laser irradiation at 775 nm, and the two-photon cross section was found to be 0.051 GM.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:NSHD.ca#10222/36323 |
| Date | 22 July 2013 |
| Creators | Ruzic-Gauthier, Michael |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
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