In this approach to structural DNA nanotechnology, three short DNA strands are attached to one aromatic ring containing six carbon atoms. By choosing the correct DNA sequences, 20 such three-legged building blocks are made to assemble into a dodecahedron. From “Nanosoftball made of DNA“:
‘Programmed’ oligonucleotides with 3 branches organize themselves into dodecahedra
For quite some time, DNA, the stuff our genes are made of, has also been considered the building material of choice for nanoscale objects. A team led by Günter von Kiedrowski at the Ruhr University in Bochum has now made a dodecahedron (a geometric shape with twelve surfaces) from DNA building blocks. As reported in the journal Angewandte Chemie [abstract], these objects are formed in a self-assembly process from 20 individual trisoligonucleotides, building blocks consisting of a “branching junction” and three short DNA strands.
…Atomic force microscopy images reveal [the dodecahedra] to be uniform particles with a diameter of about 20 nm. Under pressure, the dodecahedra are quite flexible, they can be deformed like “soft balls” without incurring any damage.
If the trisoligonucleotides are equipped with pendant “arms”, the dodecahedra can be outfitted with additional functional molecules. In this way, highly complex nanoconstructs, resembling little viruses in shape and size, should be accessible in the future. Potential applications range from medical diagnostics to nanoelectronics.
Much work has been done using complementary single strands of DNA to program the assembly of nanoparticles into three-dimensional objects (see, for example this Nanodot post from two months ago). This new work differs in that the “nanoparticles” that are assembled are atomically precise—six-member rings of carbon atoms—and the structures that result from the assembly are also atomically precise.
—Jim
