Using 10-nm-size gold nanoparticles, the DNA nanotubes form a split branch structure, with both the spiral tube splitting into two smaller stacked rings. (Credit: The Biodesign Institute at Arizona State University)
By copying a page from nature's guidebook, they capitalize on the DNA molecule's remarkable properties of self-assembly. When ribbonlike strands of the molecule are brought together, they fasten to each other like strips of Velcro, according to simple rules governing the pairing of their four chemical bases, (labeled A, C, T and G). From this meager alphabet, nature has wrung a mind-bending multiplicity of forms. DNA accomplishes this through the cellular synthesis of structural proteins, coded for by specific sequences of the bases. Such proteins are fundamental constituents of living matter, forming cell walls, vessels, tissues and organs. But DNA itself can also form stable architectural structures, and may be artificially cajoled into doing so.
In his research, Yan has been much inspired by nanoscale ingenuity in the natural world: "Unicellular creatures like oceanic diatoms," he points out, "contain self-assembled protein architectures." These diverse forms of enormous delicacy and organismic practicality are frequently the result of the orchestrated self-assembly of both organic and inorganic material.
Scientists in the field of structural DNA nanotechnology, including Dr. Yan's team, have previously demonstrated that pre-fab DNA elements could be induced to self-assemble, forming useful nanostructural platforms or "tiles." Such tiles are able to snap together -- with jigsaw puzzle-piece specificity -- through base pairing, forming larger arrays.
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