NYU (US)—Scientists from the United States and China have designed one of the world’s smallest robots. The programmable two-armed device could be used to create new DNA structures, serving as a factory of sorts for assembling the building blocks of new materials. Applications range from developing new synthetic fibers to  improving data encryption.

“The aim of nanotechnology is to put specific atomic and molecular species where we want them and when we want them there,” says NYU Chemistry Professor Nadrian Seeman, one of the study coauthors. “This is a programmable unit that allows researchers to capture and maneuver patterns on a scale that is unprecedented.”

Chemists at New York University and China’s Nanjing University developed the device that is approximately 150 x 50 x 8 nanometers. A nanometer is one billionth of a meter. Put another way, if a nanometer were the size of a normal apple, measuring approximately 10 centimeters in diameter, a normal apple, enlarged proportionally, would be roughly the size of the earth.

The creation enhances Seeman’s earlier work—a single nanorobotic arm, completed in 2006, marking the first time scientists had been able to employ a functional nanotechnology device within a DNA array.

The new, two-armed device employs DNA origami, a method unveiled in 2006 that uses a few hundred short DNA strands to direct a very long DNA strand to form structures that adopt any desired shape. These shapes, approximately 100 nanometers in diameter, are eight times larger and three times more complex than what could be created within a simple crystalline DNA array.

In the two-armed nanorobotic device, the arms face each other, ready to capture molecules that make up a DNA sequence. Using set strands that bind to its molecules, the arms are then able to change the structure of the device. This changes the sticky ends available to capture a new pattern component.

The researchers note that the device performs with 100 percent accuracy. Earlier trials revealed that it captured targeted molecules only 60 to 80 percent of the time. But by heating the device in the presence of the correct species, they found that the arms captured the targeted molecules 100 percent of the time.

They confirmed their results by atomic force microscopy, which permits features that are a few billionths of a meter to be visualized.

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