Title: The Design of Complex Material aided by DNA Nanotechnology
Description: DNA nanotechnology represents a powerful medium for manipulating the nanoscale arrangement of functional components. The first 15 years of DNA explorations has fast reached into every area of science and technology. Our group has focused attention on the utility of DNA as a structural material by folding DNA into rigid DNA objects such as tetrahedron or octahedron. These objects form the basis for engineered self-assembly by activating vertices of the nano-objects to interact with each other allowing for DNA mediated interaction which can achieve long range ordered cellular structures. Application of DNA nanotechnology can be likened to generating a flexible platform leveraging the precision afforded by the DNA sequences of A,G,T,C, and mostly are limited to experiments that could be accomplished within a 1μm3 volume. To scale emergent properties on the nanoscale, DNA origami techniques need profound improvements in synthesis and tools for characterization. The roadmap to transition DNA origami from a test tube to practical applications required a number of developments undertaken in this body of work.

Critical milestones included: 1. Knowledge of nucleation and growth of DNA crystals (Chapters 1-3) 2. Transitioning DNA origami structures to the solid state (Chapters 4-7) 3. Characterization techniques to evaluate hierarchically engineered objects (Chapters 8-9) In the first thrust we performed investigative studies into the growth and nucleation of DNA origami crystals investigating thermodynamics and kinetics via in-situ experiments, these results iteratively improved synthesis conditions of DNA origami superlattices to grow from ~1um to over 250um single crystals up to 10x faster compared to previous synthesis conditions. These developments worked in tandem to explore methods to transition DNA constructs to the solid state via sol-gel synthesis of silica. The conversion process was reduced from by a factor of 12 from 24 hours to 2hours for rapid evaluation of crystals leveraged by a number of projects. The silication of structures allowed for further expanding the library of chemical structures available through the integration of liquid infiltration, atomic layer deposition and direct metallization of structures.

The rapid development of DNA superlattices into larger and more complex motifs required the development of characterization techniques which could evaluate hierarchically designed materials spanning from 3-4nm to over 100 um. We characterize bulk mechanical properties of silica nanolattices leveraging in-situ indenters to examine nanoscale failure mechanisms. To characterize superlattices real-space artifacts we developed tomographic techniques to explore the spatial and elemental distribution of engineered constructs along with adopting biological serial sectioning approaches to evaluate defects in the assemblies.