Credit: © 2008 AAAS

Absolute control over the dimensions of a structure is a primary goal of nanotechnology. To this end, DNA is proving to be one of the most versatile building blocks. DNA can be used to form rigid tiles with 'sticky ends' capable of binding other tiles and directing the formation of a design. Using such methods, a range of two- and three-dimensional nanoscale architectures have been created, including tubes. However, controlling the circumference and uniformity of these nanotubes has proved difficult. Peng Yin and colleagues1 at the California Institute of Technology and Duke University now report the synthesis of molecular tubes with programmable circumferences by using flexible DNA motifs.

The research team used a 42-base single-stranded DNA motif with four modular domains. By pairing up complementary domains, it was possible to organize the motifs into DNA lattices made up of parallel helices with single-stranded linkages. In the lattice, the motif configures into a rectangular, tile-like geometry, which is connected to four adjacent neighbours. The circumference of a molecular tube can then be programmed by specifying the modular interactions between the motifs.

To execute this 'molecular programme', one-pot annealing of the DNA strands is all that is required, and monodispersed nanotubes with designed circumferences from four to twenty DNA helices can be synthesized.