DNA Glass: Encasing Diffraction-Quality, Mesoporous DNA Crystals in Architected Silica

Self-assembling DNA crystals have emerged over the last two decades as an efficient and effective means of organizing matter at the nanoscale, but functionalization of these lattices has proved challenging as physiological buffer conditions are required to maintain structural integrity. In this manuscript, we demonstrate the silicification of mesoporous DNA crystals using sol-gel chemistry. We identify reaction conditions that produce the minimum coating thickness to confer environmental protection, and we subsequently measure this protective ability to various stressors, including heat, low ionic strength solution, organic solvents, and unprotected freezing. By soaking metal ions and dyes into the lattice after silica coating, we demonstrate that the crystals maintain their pores and that the major groove of the DNA can still be used as a sequence-specific template for chemical reactions. We image a library of different crystal motifs by electron microscopy, and we perform X-ray diffraction on these crystals, both with and without cryoprotection, to determine the structure of the DNA frame, underscoring the conserved molecular order after coating. We anticipate these mesoporous silica composites will find use in applications involving extreme, nonphysiological conditions and in experiments which utilize the DNA glass described here as a template for chemical reactions on the internal surface of architected materials.