March 15, 2006

DNA nanotechnology: DNA oragami example of current capability

Impressive progress is being made towards DNA nanotechnology.

A map of the Americas measuring just a few hundred nanometres across has been created out of meticulously folded strands of DNA, using a new technique for manipulating molecules dubbed "DNA origami". More information is here The "DNA origami" procedure laid out by Paul Rothemund of the California Institute of Technology could be adapted to create nano-computers, new drug delivery systems or even molecular-scale chemical factories. Rothemund said the process is so simple that high-school students should be able to design woven DNA patterns, but so versatile that scientists could build complex structures for a wide variety of nanotechnology applications.

"A physicist, for example, might attach nano-sized semiconductor 'quantum dots' in a pattern that creates a quantum computer," he said. "A biologist might use DNA origami to take proteins which normally occur separately in nature, and organize them into a multi-enzyme factory that hands a chemical product from one enzyme machine to the next in the manner of an assembly line."

Rothemund's technique uses chemicals to twist a long, single-stranded DNA molecule into a predetermined shape, then "staples" the scaffolding together with crossover strands.

The nanoscale map, which sketches out both North and South America at a staggering 200-trillionths of their actual size, aims to demonstrate the precision and complexity with which DNA can be manipulated using the approach.

To make the design process less complicated, Rothemund created software that works out which short-strand sequences will generate different shapes. Rothemund says it should be possible to precisely arrange quantum dots or carbon nanotubes after chemically binding them to DNA, using the method.

William Shih at the Biomolecular Nanotechnology Group at Harvard Medical School in Boston, US, says this offers the most flexible method yet for building nanoscale structures. Shih is experimenting with the technique as a means of making molecular 3D cages, which could be used to build molecular motors.