DNA nanotechnology has been enormously successful in using DNA as a nanoscale construction material, and consistent progress in using increasingly complex DNAmediated assemblies and designs has been reported in the literature. However, the field of DNA nanostructures has sometimes been lacking for concrete applications. Meanwhile, DNA has also been widely used as probes and primers for nucleic acid diagnostics applications, and this provides an extremely critical application with potential for great medical benefits, and these DNA probes and primers are readily interfaced with DNA nanotechnology. Thus, in this Dissertation, I discuss the combination of (1) DNA in its role as a recognition element for nucleic acid detection, and (2) DNA as a structural material for nanoscale self-assembly. This combination represents a fusion of "structure" and "function", and will ultimately lead to great advancements in the field of nucleic acid diagnostics. iii