Materials Science

Stringing DNA Along

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Science  12 Feb 2010:
Vol. 327, Issue 5967, pp. 762-763
DOI: 10.1126/science.327.5967.762-d

The high base-pairing fidelity of DNA makes the biopolymer a powerfully versatile templating material for precise nanoscale fabrication. Unfortunately. it is costly to prepare long sequences and thus to direct structure over a long range. In contrast, synthetic block copolymers are well suited to creating periodic structures over long distances because of the microphase separation of the covalently linked blocks that ensues in a selective solvent. Carneiro et al. attached a dendritic oligo(ethylene glycol) (OEG) unit to one end of 10– to 20–base pair DNA oligomers. Hybridization with the complementary DNA strands then formed a triblock, with dendritic units at either end that could assemble into long fibers when a selective solvent was added. The fibers extended for several micrometers and could further align into parallel rows. Fiber formation could be tuned or eliminated by changing the ratio of DNA to OEG or by changing the number of arms on the OEG. More complex structures could also be prepared by hybridizing three linking strands to three dendritic DNA strands, yielding a three-helix bundle that, despite the internal complexity, could still form long ordered strands.

J. Am. Chem. Soc. 132, 679 (2010).

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