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Nanotechnology may have found its Henry Ford

Tiny DNA robots could be the future of assembly lines.

By Jesse EmspakContributor for The Christian Science Monitor / March 27, 2009



Nadrian Seeman sees a future filled with extremely small factory workers.

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By small, the New York University chemistry professor means a billionth of a meter.

That’s the scale that he and others who work in the field of nanotechnology deal with on an everyday basis. By manipulating molecules, they attempt to build new materials and microscopic robots, possibly small and smart enough to move through human bodies.

But nanotechnology’s key obstacle has always been how to mass-produce these exotic molecules used as building blocks.

At this early stage, nanoscale manufacturing mistakes are pretty common. It would be as though a factory churned out cars where the rearview mirror was attached to the hood – and did so a third of the time.

But Professor Seeman has found a way around that. He and a Chinese team at Nanjing University have built a nanoscale factory worker. The tiny machine is made of DNA, the molecule that governs the way cells make proteins. But this DNA isn’t like that found in human cells – it’s synthetic and can’t reproduce by itself.

But like all DNA, it holds information in the form of genetic code. Seeman “programs” his tiny machine by stringing the right combinations of DNA – much in the way computer engineers use binary code.

“We’re prototyping the notion of programmable patterns,” Seeman says.

The machine has two “arms” made of strings of DNA that are attached by another chain of DNA.

Each arm has a molecule on the end that attaches to other molecules and aligns them in a set order. These sticky ends only connect with a particular building block, and Seeman can program them to specify which molecule he wants.

This allows him to arrange pieces and form specific molecules with some precision – similar to the way a robotic automobile factory can be told what kind of car to make.

After the arms create the desired molecules one at a time, the whole mixture is heated and cooled, which causes the correct molecules to displace the incorrect ones.

This fixes any errors and is what makes the “factory” reliable enough to mass-produce.

Thus far, Seeman’s team has made molecules with various shapes – squares and triangles – that don’t have a specific function. The next step is constructing functional molecules – but he is mum on the details.

He imagines building several tiny DNA machines and programming them to work in harmony, creating more complex substances such as a fiber or even an electronic device.

Seeman has been working on nanorobotics for several years. He first perfected a one-armed version in 2006. It was the first time anyone had put together such a device in a DNA array, he says.

Now, that he’s pulled off a two-arm design, Seeman says that his team can finally build things.

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