Distinguished Lecture - From the Blueprint of Life to Programmable Assembly: Engineering Colloidal Crystals with DNA

Assembly of nanoscale building blocks into superstructures, where the emergent properties are determined not only by the properties of the building blocks but also by the symmetry, orientation, phase, and dimension of the resulting superstructures, are fundamental in expanding the understanding of material crystallization and developing functional metamaterials. However, precisely controlling the length at nanoscale remains challenging in developing crystalline materials with tailorable properties. Professor Mirkin's research group uses DNA as a programmable material to guide the assembly of nanoscale building blocks into colloidal superstructures, with crystal symmetries, habits, and properties dictated by nucleic acid interactions. This programmable strategy of using DNA as “bonds” allows for easy control over nucleic acid sequences and lengths and has led us to define a powerful set of design rules for the construction of colloidal crystals with more than 78 lattice symmetries spanning the classic 14 Bravais lattices, and eight well-defined crystal habits without any atomic lattice equivalents or mineral equivalents. We have expanded this strategy to hollow nanoframes and non-space filling nanostructures to form open-channel lattices, Kagome lattices, and mechanical metamaterial with controllable topology and sizes. These programmable superstructures feature highly ordered solid nanoparticles bonded by soft, deformable DNA strands and have many remarkable physical properties and unprecedented mechanical strength distinct from individual building blocks. For example, DNA-bonded crystals have shape memory properties and restore their crystallinity and habit after 90% compression during dehydration. Exotic optical properties have also been observed in DNA-engineered colloidal crystals, including wavelength-dependent reflection, second harmonic generation, and negative refraction indicating a new milestone in the design of programmable metamaterial.

 

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