Nanosoftball made of DNA( This release is available in A HREF h...)

This release is available in German.

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 Gnter 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, 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.

A regular dodecahedron is a geometric shape made of 12 pentagons of equal size, three of which are connected at every vertex. This results in a structure with 30 edges and 20 vertices. In order to produce a hollow dodecahedral object from DNA, the researchers used 20 three-legged building blocks (three DNA strands connected together at one point). The centers of these building blocks represent the vertices of the dodecahedron. The three edges projecting from each vertex are formed when a single strand of DNA converts two neighboring bridging components into a double strand.

In order for this process to result in a dodecahedron and not some other random geometric object, all of the DNA strands must have a different sequence. Among these, there must, however, be pairs of complementary strands that can bind to each other.

By using a computer program, the researchers identified a set of 30 independent, 15-base-pair-long, double-stranded DNA sequences with similar physical properties. The double-stranded sequences were assigned to the individual edges of the dodecahedron and to specific vertices for termination. It was then determined which three single-stranded sequences needed to be attached to each three-legged junction for the predetermined structure to form.

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