DNA, normally the building block of life, is being used to build engineered nano-structures instead. The double helix that forms when two strands of DNA intertwine resembles a twisted ladder, in which the paired bases form the rungs. Crucially, a base on one side of the ladder will only pair up with a specific partner on the other leg.
University of Oxford physicist Andrew Turberfield and his colleagues have exploited this pairing to build a different kind of structure. They designed four single strands of synthetic DNA on which base pairs were strategically placed to zip the strands together into a rigid pyramid about 10 nanometres high.
The team has also joined pairs of pyramids by removing part of one DNA strand and replacing it with a “linker” strand complementary to the exposed base pairs. The free end of the linker DNA attaches to a second pyramid treated in the same way, in effect tying the two blocks together (Science, vol 310, p 1661).
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Turberfield suggests that the blocks could one day be used to create “nano-scaffolding” on which 3D molecular electrical circuits could be built. The pyramids could also be used to cage individual protein molecules, which could one day assist in new methods of drug delivery.
