Temperature-Controlled Assembly Kinetics of DNA-Functionalized Gold Nanoparticles

  • Author / Creator
    Dever, Brittany R
  • The assembly of nanoparticle building blocks into more complex nanostructures has important applications in analytical chemistry, materials science, medical science, optics, and electronics. Due to its exquisite specificity and programmable nature, DNA has emerged as a very promising biomolecule to facilitate the assembly of nanomaterials. DNA-conjugated gold nanoparticles (AuNP) have been used in a wide range of assays and have also been assembled into discrete nanostructures, two-dimensional arrays, and three-dimensional crystal structures. This thesis focuses on how temperature impacts the assembly kinetics of DNA-functionalized AuNPs and applying the findings to the development of analytical assays. A temperature effect on the assembly kinetics of AuNPs was discovered. As the temperature increased, the assembly kinetics increased up to a critical temperature (Tcrit). At temperatures higher than Tcrit, the assembly kinetics were drastically reduced. This very sharp transition from maximal assembly kinetics at Tcrit to minimal assembly kinetics at higher temperatures (2-3 °C) has not been reported in literature. The impact of various experimental parameters on the Tcrit¬ and the sharpness of the transition in the temperature-dependent assembly kinetics (TDAK) profile were studied. Parameters studied included the sodium chloride concentration, the amount of DNA on the AuNP surface, the linker concentration, and the presence of gaps and overhangs present in the linker sequence. The temperature dependent assembly kinetic phenomenon was used to design a colorimetric assay that could detect single nucleotide polymorphisms (SNPs) within five minutes. This strategy was used to detect a SNP that conferred first line drug resistance in Mycobacterium tuberculosis. Temperature-dependent assembly kinetics was also applied to develop a strategy to sequentially control the assembly of three different DNA-AuNPs in a single solution. These results demonstrate the broad applications that temperature-dependent assembly kinetics of DNA-AuNPs can have in assay development and the synthesis of more complex nanostructures from nanoparticle building blocks. With the promising applications that nanotechnology has to offer, temperature-dependent assembly kinetics offers a novel tool to selectively assemble nanomaterials in solution to aid in the advancement of nanoscience.

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  • Degree
    Doctor of Philosophy
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    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.