Chemistry

Big Steps for Little Feet

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Science  08 Jan 2010:
Vol. 327, Issue 5962, pp. 127
DOI: 10.1126/science.327.5962.127-b

Macroscopic robots can already walk—the trouble is getting them to think. At the molecular scale, though, channeling stochastic motion into something resembling a series of purposeful strides is still a great challenge. Von Delius et al. now show that carefully designed feet appended to a small hydrocarbon chain can shuffle to and fro along a four-site track under proper chemical stimulation. One foot forms disulfide bonds to two of the track sites, whereas the other forms hydrazone linkages to interspersed sites. By introducing acids or bases that selectively favor these respective reactions, the authors shift the chain's position one step at a time. Replacing the base treatment with a redox protocol asserts some degree of control over the directionality of the stroll.

Nat. Chem. 10.1038/nchem.481 (2009).

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