A team of researchers from the University of Illinois Urbana-Champaign has developed a tiny, four-fingered “hand” folded from a single piece of DNA that is capable of picking up the virus that causes COVID-19.

According to its developers, the aptly name NanoGripper is designed to expedite the detection of the virus as well as block viral particles from entering cells to infect them. Additionally, the nanorobotic hand could be programmed to interact with other viruses or identify cell surface markers, enabling targeted drug delivery for applications like cancer treatment.

Source: Xing Wang, University of Illinois

The NanoGripper consists of a single nanostructure created from a folded DNA strand, forming a palm and four flexible fingers. Each finger includes three joints, similar to human fingers, with the bending angles and degrees precisely determined by the DNA scaffold's design.

“We wanted to make a soft material, nanoscale robot with grabbing functions that never have been seen before, to interact with cells, viruses and other molecules for biomedical applications,” the researchers explained. “We are using DNA for its structural properties. It is strong, flexible and programmable. Yet even in the DNA origami field, this is novel in terms of the design principle. We fold one long strand of DNA back and forth to make all of the elements, both the static and moving pieces, in one step.”

The researchers noted that each finger of the NanoGripper is equipped with DNA aptamer regions designed to bind to specific molecular targets — in this case, the spike protein of the virus responsible for COVID-19. This binding triggers the fingers to bend and wrap around the target. Additionally, the NanoGripper’s "wrist" area can attach to surfaces or larger complexes, enabling biomedical applications like sensing or targeted drug delivery.

To enable the detection of the COVID-19 virus, the team paired the NanoGripper with a photonic crystal sensor platform to develop a rapid, 30-minute COVID-19 test. The team explained that when the virus is held in the NanoGripper’s hand, a fluorescent molecule releases light when illuminated by an LED or laser. In the event that several fluorescent molecules are concentrated upon a single virus, it is bright enough in the detection system so that each virus can be counted individually.

Beyond diagnostics, the NanoGripper could also be used to block viruses from entering and infecting cells, the researchers added. The team determined during trials that when NanoGrippers were added to cell cultures exposed to COVID-19, multiple grippers wrapped around the outside of the viruses, thus blocking the viral spike proteins from interacting with receptors on the cells’ surface, and, consequently, preventing infection.

Likewise, the team believes that the NanoGripper could be engineered to target other viruses — like influenza, HIV or hepatitis B — or for targeted drug delivery.

The paper, “Bioinspired designer DNA NanoGripper for virus sensing and potential inhibition,” appears in the journal Science Robotics.