The first section of this thesis focuses on applications of DNA-modified gold nanoparticles (AuNPs) while the second part addresses the fundamental properties that arise from conjugating DNA to inorganic AuNPs. Two types of applications are discussed. The first application utilizes the colorimetric properties of AuNPs to screen duplex and triplex DNA binding molecules. Small molecules that bind to double and triple helix DNA often stabilize the DNA helix and increase the denaturation temperature. These molecules are of interest for their properties as anti-cancer drugs and gene regulation agents. When these molecules are combined with AuNP assemblies linked with DNA, the small molecules bind to the DNA interconnects and stabilize the assembly. The increased stability of the assembly can be monitored as a function of temperature and the relative binding strength of the DNA binders can be assessed. These assays have been further developed for processing in a chip based format. DNA-modified AuNPs also have been used to build complex higher order architectures. These materials can be programmed to assemble based upon the DNA recognition properties, however, control over the architectural parameters of these structures have been limited. In this thesis, we demonstrate the ability to utilize the synthetic programmability of DNA to direct the organization of AuNPs into different crystalline structures, depending upon the choice of DNA linkers and environmental conditions. FCC and BCC structures are investigated in detail by synchrotron small angle X-ray scattering experiments. The fundamental properties of these materials, specifically the enhanced binding properties and the sharp melting transitions, are investigated. Concentration dependent melting studies are performed to gain quantitative data about the thermodynamic properties of DNA-modified AuNPs. These data indicate that DNA-modified AuNPs can exhibit two orders of magnitude enhanced binding strength compared to molecular fluorophore-modified DNA, depending upon sequence length. The enhanced binding properties are attributed to the high DNA density at the AuNP surface. The sharp melting transitions are investigated by assembling DNA-modified AuNPs with peptide nucleic acid linkers and then monitoring the melting transitions. The data suggest that a cooperative element is integral to understanding the melting properties of these assemblies.

Last modified

• 08/27/2018

Creator

• Abigail K. R. Lytton-Jean

DOI

• https://doi.org/10.21985/N2RB15

Subject

• Chemistry

Keyword

• Chemistry

Date created

• 2007-11-07

Resource type

• Dissertation

Rights statement

• In Copyright