Dynamic DNA Nanotechnology for Probing Single Nucleotide Variants and DNA Modifications

Abstract

In the last decades, various DNA hybridization probes have been developed that attempt to conquer the challenge of single-nucleotide-variants (SNVs) detection. Even though a powerful toolbox including the toehold-exchange reaction, the dynamic ‘sink’ design, and the polymerase chain reaction (PCR) has been built, it still faces practical problems. For example, the natural DNA is usually in double-stranded form whereas most hybridization probes aim for single-stranded targets; the concentration of extracted DNA samples is totally unknown thus may lay outside the optimal design of probes/primers. To achieve ultra-high sensitivity and specificity, expensive and sophisticated machines such as digital droplet PCR and next-generation-sequencing may be inapplicable in rural areas. Therefore, the quantitative PCR method is still the gold standard for clinical tests. Thus motivated, my PhD career was mainly focused on the fundamental understanding of the challenges in SNVs discrimination and developing robust, versatile, and user-friendly probes/strategies. In this thesis, Chapter 1 provides a general introduction of dynamic DNA nanotechnology and its representative applications in discriminating SNVs. Chapter 2 to 4 describe three completed projects that aim to understand the thermodynamic and kinetic properties of strand displacement reactions and to circumvent the challenges of discriminating SNVs through finely tuned probes/assays.