DNA sensor determines viral infectivity

Researchers at the University of Illinois Urbana-Champaign and collaborators developed the sensor, which integrates specially designed DNA fragments and nanopore sensing, to target and detect infectious viruses in minutes without the need to pre-treat samples. They demonstrated the sensor’s power with two key viruses that cause infections worldwide: the human adenovirus and the virus that causes COVID-19. Yi Lu, a professor emeritus of chemistry, and Benito Marinas, a professor of civil and environmental engineering, co-led the work with University of Illinois Chicago professor Lijun Rong; professor Omar Azzaroni, of the National University of La Plata in Argentina; and María Eugenia Toimil-Molares, of the GSI Helmholtz Centre for Heavy Ion Research in Germany. They reported their findings in the journal Science Advances.

“The infectivity status is very important information that can tell us if patients are contagious or if an environmental disinfection method works,” said Ana Peinetti, the first author of the study, who performed the work while a postdoctoral researcher at Illinois. She now leads a research group at the University of Buenos Aires in Argentina. “Our sensor combines two key components: highly specific DNA molecules and highly sensitive nanopore technology. We developed these highly specific DNA molecules, named aptamers that not only recognize viruses but also can differentiate the infectivity status of the virus.” The “gold standard” of viral detection, PCR tests detect viral genetic material but cannot distinguish whether a sample is infectious or determine whether a person is contagious. This can make it more difficult to track and contain viral outbreaks, the researchers said.

Tests that detect infectious viruses, called plaque assays, exist but require special preparation and days of incubation to render results. The new sensing method can yield results in 30 minutes to two hours, the researchers report, and since it requires no pre-treatment of the sample, it can be used on viruses that will not grow in the lab. Being able to distinguish infectious from noninfectious viruses and to detect small amounts from untreated samples that may contain other contaminants is important not only for rapid diagnosis of patients who are in the early stage of infection or who are still contagious after treatment, but for environmental monitoring as well, Marinas said. The sensing technique could be applied to other viruses, the researchers say, by tweaking the DNA to target different pathogens.

Source: University of Illinois Urbana-Champaign news release