A miniature, four-fingered “hand” made from a single strand of DNA is capable of detecting the COVID-19 virus rapidly and sensitively, as well as preventing viral particles from infecting cells, according to researchers. This innovative device, known as the NanoGripper, can also be programmed to interact with different viruses or identify specific cell surface markers for targeted drug delivery, for instance, in cancer therapies.
A miniature, four-fingered “hand” sculpted from a single DNA strand can effectively identify the COVID-19 virus for swift and sensitive detection while having the ability to block viral particles from penetrating cells, as reported by researchers from the University of Illinois Urbana-Champaign. This creation, referred to as the NanoGripper, may also be programmed to engage with various other viruses or detect specific cell surface markers for tailored drug delivery, such as in cancer treatment.
Under the leadership of Xing Wang, a professor in both bioengineering and chemistry at the University of Illinois, the team details their breakthrough in the journal Science Robotics.
Taking inspiration from the gripping function of human hands and bird talons, the researchers crafted the NanoGripper with four flexible fingers and a palm, all made from one nanostructure derived from a single DNA strand. Each finger has three joints, similar to a human finger, with the angle and extent of bending dictated by the DNA design.
“Our goal was to create a soft, nanoscale robot with grasping capabilities that have never been realized before for interacting with cells, viruses, and other molecules in biomedical applications,” Wang explained. “We utilize DNA due to its structural characteristics; it is robust, adaptable, and programmable. However, from the perspective of DNA origami, this design principle is quite novel. We have folded one continuous strand of DNA back and forth to create both the fixed and moving parts in a single process.”
The fingers incorporate regions called DNA aptamers, which are specifically designed to bind with molecular targets — such as the spike protein of the virus responsible for COVID-19 in this initial application — prompting the fingers to bend and encircle the target. On the wrist side, the NanoGripper can attach to a surface or larger complex for biomedical uses, like sensing or drug delivery.
In collaboration with a group led by Professor Brian Cunningham from Illinois’ electrical and computer engineering department, who is an expert in biosensing, Wang’s team integrated the NanoGripper with a photonic crystal sensor platform. This fusion resulted in a rapid COVID-19 test that takes only 30 minutes, yet maintains the sensitivity of the gold-standard qPCR molecular tests utilized in hospitals — known for their accuracy but longer processing time compared to at-home tests.
“Our test is extremely quick and straightforward since we are detecting the virus in its intact form,” noted Cunningham. “When the virus is grasped by the NanoGripper, it activates a fluorescent molecule that emits light when hit by an LED or laser. This concentration of fluorescent molecules on a single virus results in a brightness sufficient in our detection system to count each virus separately.”
Beyond diagnostics, the NanoGripper has the potential to act in preventive medicine by obstructing viruses from infiltrating and infecting cells, Wang stated. Experiments showed that when NanoGrippers were introduced to cell cultures exposed to COVID-19, multiple grippers would encircle the viruses, hindering the viral spike proteins from binding with receptors on the cells’ exterior to stave off infection.
“Applying it post-infection would be quite challenging, but we can propose a preventive therapeutic,” Wang shared. “One possibility is developing a nasal spray with the NanoGripper. The nasal cavity is a common entry point for respiratory viruses, such as COVID or influenza. A NanoGripper-based nasal spray might prevent inhaled viruses from interacting with nasal cells.”
The NanoGripper could be tailored to target additional viruses, including influenza, HIV, or hepatitis B, according to Wang. Furthermore, he envisions utilizing the NanoGripper for targeted drug delivery, allowing the fingers to be programmed to recognize specific cancer markers, delivering cancer-fighting therapies directly to the affected cells.
“This approach holds vast potential beyond the limited illustrations we have shown in this study,” Wang emphasized. “There are necessary modifications to be made regarding the 3D structure, stability, and the targeting aptamers or nanobodies, but we have devised several techniques to accomplish this in the lab. Naturally, extensive testing will be necessary; however, the prospective uses for cancer treatment and diagnostic sensitivity showcase the capabilities of soft nanorobotics.”
The National Institutes of Health and the National Science Foundation provided funding for this research. Wang and Cunningham are associated with the Carl R. Woese Institute for Genomic Biology and the Holonyak Micro and Nanotechnology Lab at the University of Illinois.
For media inquiries, contact Xing Wang at xingw@illinois.edu.
The research paper titled “Bioinspired designer DNA NanoGripper for virus sensing and potential inhibition” can be accessed through robopak@aaas.org. DOI: 10.1126/scirobotic.
This research received support in part from NIH grants R21EB031310, R44DE030852, and R21AI166898.
