Stress\nin DNA Gridiron Facilitates the Formation of\nTwo-Dimensional Crystalline Structures

Abstract

Programmable\nDNA nanotechnology has generated some of the most\nintricate self-assembled nanostructures and has been employed in a\ngrowing number of applications, including functional nanomaterials,\nnanofabrication, biophysics, photonics, molecular machines, and drug\ndelivery. An important design rule for DNA nanostructures is to minimize\nthe mechanical stress to reduce the potential energy in these nanostructures\nwhenever it is possible. This work revisits the DNA gridiron design\nconsisting of Holliday junctions and compares the self-assembly of\nthe canonical DNA gridiron with a new design of DNA gridiron, which\nhas a higher degree of mechanical stress because of the interweaving\nof DNA helices. While the interweaving DNA gridiron indeed exhibits\nlower yield, compared to its canonical counterpart of a similar size,\nwe discover that the mechanical stress within the interweaving gridiron\ncan promote the formation of the two-dimensional crystalline lattice\ninstead of nanotubes. Furthermore, tuning the design of interweaving\ngridiron leads to the change of overall crystal size and regularity\nof geometry. Interweaving DNA double helices represents a new design\nstrategy in the self-assembly of DNA nanostructures. Furthermore,\nthe discovery of the new role of mechanical stress in the self-assembly\nof DNA nanostructures provides useful knowledge to DNA nanotechnology\npractitioners: a more balanced view regarding mechanical stress can\nbe considered when designing future DNA nanostructures.