| It is clear that remarkable progress has been made in understanding the fundamental properties of and potential applications for polyvalent DNA-gold nanoparticle conjugates (Chapter 1). Many important questions have been answered yet many still remain. The work presented in this dissertation will delve into several of these issues.;In Chapter 2, methods are outlined that can be used to finely tune the DNA density on the surface of gold nanoparticles ranging from 15 to 250 nm in diameter. Until this study, the experimental parameters that could be used to maximize DNA loading on the surface of gold nanoparticles were not well understood and a reliable protocol for functionalizing gold nanoparticles up to 250 nm in diameter with a high density of DNA did not exist.;Using the protocols presented in these studies, a series of DNA-gold nanoparticle probes with a range of valencies, particle sizes, and DNA compositions were synthesized and the effect of such architectural modifications on the cooperative properties of these structures were explored, particularly in terms of elucidating and controlling the nature of their "three-dimensional hybridization" to form nanoparticle aggregate structures (Chapters 3 and 4). These studies also allowed comparisons to be drawn between the stability of free duplex DNA and duplex DNA immobilized on the nanoparticle surface.;The results obtained in these investigations are of textbook importance in understanding the fundamental behavior of nanoscale systems, but also serve a practical purpose. These principles can be used to precisely and dependably tailor the architecture (and as a result the properties) of DNA-Au NP conjugates to fit a specific purpose in a given application. For instance, Chapter 5 highlights a DNA-Au NP-based, colorimetric scheme, that relies on nanoparticle hybridization events, that can be used to determine the selectivity of DNA binding molecules for particular sequences of DNA.;Finally, Chapter 6 presents a short summary of the advances enabled by this work and provides insight into ways these topics can be moved forward in the future both in the fundamental and applied realms. |
