Ronit Freeman, a UNC-Chapel Hill associate professor of biomedical engineering and applied physical sciences, studies the way coronaviruses enter cells as well as how to simplify the COVID-19 testing process. (Credit: UNC)

Researchers have designed a rapid sensing COVID-19 test to meet the challenge of universal testing and tracking variants. The test takes advantage of the virus’ sweet tooth in the design of a sugar-coated COVID-19 test strip that’s been effective at detecting all known variants of the coronavirus, including delta.

The test is inspired by the natural biology of epithelial cells — those that are targeted and infiltrated by SARS-CoV-2, the virus that causes COVID-19. These cells are coated with a dense matrix of sugars called the glycocalyx, and it’s this sugar net that the virus exploits to cause infection.

The concept is intuitive: a droplet of biofluid containing the virus, such as saliva, is placed on one end of the strip and flows along the surface. When the fluid reaches a sugar-coated patch, the virus can’t help but indulge its sweet tooth, becoming trapped on that specific area. This capture is then signaled by antibodies treated with gold nanoparticles producing a visual color that indicates infection.