Sugar-Coated COVID-19 Test Strip Detects All Known Coronavirus Variants

By LabMedica International staff writers
Posted on 16 Dec 2021

Researchers have taken advantage of the coronavirus’ sweet tooth by designing a sugar-coated COVID-19 test strip that has proved effective at detecting all known variants of the virus, including delta.

In the next few weeks, researchers at the University of North Carolina at Chapel Hill (Chapel Hill, NC, USA) and University of California San Diego (La Jolla, CA, USA) will determine if the self-test known as GlycoGrip can detect infections caused by the omicron variant as well. 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.

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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.

To better understand how these sugar polymers bind the virus, the team developed computationally intensive simulations that helped explain the mechanics behind how and why the cell-anchored sugars bind the viral spikes. One of the greatest challenges of the ongoing COVID-19 pandemic has been responding to the virus’ mutations and emerging variants. New tests must be developed for new tweaks in the virus’ genetic code. But GlycoGrip offers a solution for universal coronavirus testing.

“We have turned the tables on the virus by using the same sugar coat it binds to infect cells – to capture it into our sensor,” said Carolina researcher Ronit Freeman. “We tapped into nature to reimagine viral diagnostics. We are optimistic that GlycoGrip will capture future variants just as easily.”

“By using atomic-level views of the spike protein, we were able to identify key binding sites for the glycocalyx sugar polymers and unlock how these sugars adapt to different spike conformations,” said Rommie Amaro, professor of chemistry and biochemistry at the University of California San Diego. “This is exciting, we essentially revealed another secret of how spike binds cells to facilitate infection.”