Designed DNA Crystal Habit Modifiers.

DNA is now one of the most widely used molecules for programmed self-assembly of discrete nanostructures. One of the long-standing goals of the DNA nanotechnology field has been the assembly of periodic, macroscopic 3D DNA crystals for controlled positioning of guest molecules to be used in a variety of applications. With continuing successes in assembling DNA crystals, there is an enhanced need to tailor macroscopic crystal properties-including morphology-to enable their integration into more complex systems. Here we describe the ability to alter and control crystal habits of a 3D DNA crystal formed by self-assembly of a DNA 13-mer. The introduction of "poison" oligonucleotides that specifically disrupt critical noncanonical base-pairing interactions in the crystal lattice leads to predictably modified crystal habits. We demonstrate that the poison oligomers can act as habit modifiers both during the initial crystallization and during growth of shell layers on a crystal macroseed.