Nanoscale robotic ‘hand’ made of DNA could be used to detect viruses

A nanoscale robotic hand with four bendable fingers can grab objects such as gold nanoparticles and viruses.

Xing Wang and colleagues at the University of Illinois constructed a nanohand using a method called DNA origami. In this method, long single-stranded DNA is “stapled” by short pieces of DNA that pair with specific sequences on the long strand. Using this method, complex shapes can be created, from maps of the Americas to spinning nanoturbines.

The Nano Hand’s four fingers are joined in a “palm” that forms a cross when the hand is open. Each finger is only 71 nanometers long (1 nanometer is one billionth of a meter), and like a human finger, he has three joints.

The researchers conducted a series of experiments to show what the hands could be used for. To demonstrate the grasping ability, they added strips of complementary DNA to gold particles 50–100 nanometers in diameter and were able to grasp them with their fingers.

In another experiment, they took a finger and added a piece of DNA that binds to the spike protein of the SARS-CoV-2 virus. The nanohand was then able to “grab” the virus, rendering it unable to infect cells growing in culture.

Wang and colleagues have also designed nanohands that fluoresce when bound to specific viruses, which could help detect such infectious agents. They are now studying whether the device can be used to get drugs into cells, Wang said.

One advantage of nanohands in such applications is that normal DNA is rapidly degraded by enzymes in the blood, whereas DNA origami structures are more stable. You can also make it last longer by using ultraviolet light to create extra bonds between strands or by coating the strands with certain polymers, Wang says.

“We started doing animal experiments, but not so long ago we used different DNA nanostructures,” he says.

“The designs are very unique and may inspire others,” says Matthew Aquilina of the University of Edinburgh, UK.