Sugar-coated COVID-19 test takes advantage of coronavirus sweet tooth


(CHAPEL HILL, North Carolina – December 15, 2021) Even those who follow every new discovery about the coronavirus and its variants may not be aware of the virus’s sugar cravings.

Researchers at the University of North Carolina at Chapel Hill and the University of California at San Diego are taking advantage of the virus’s sweet tooth to design a sugar-coated COVID-19 test strip that has been effective in detecting all known variants of the coronavirus, including delta.

Over the next few weeks, researchers will determine whether the self-test known as GlycoGrip can also detect infections caused by the omicron variant, said Ronit Freeman, a researcher in Carolina.

“We turned the tide on the virus by using the same layer of sugar that it binds to infect cells – to capture it in our sensor,” said Freeman, who published the results in ACS Central Science.

The test draws on 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 covered with a dense matrix of sugars called glycocalyx, and it is this trickle of sugar that the virus uses to cause infection.

The concept is intuitive: a drop of biofluid containing the virus, such as saliva, is placed at one end of the strip and flows along the surface. When the liquid reaches a sugar coated area, the virus cannot help but satisfy 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.

“We have drawn on nature to reinvent viral diagnostics,” said Freeman, co-author of the article and associate professor of applied physical sciences and biomedical engineering at UNC-Chapel Hill College of Arts & Sciences.

To better understand how these sugar polymers bind to the virus, Freeman got in touch with Rommie Amaro, professor of chemistry and biochemistry at the University of California at San Diego and co-author of the study.

Amaro and his team developed intensive computer simulations that helped explain the mechanics behind how and why sugars embedded in cells bind to viral spikes.

“Using atomic level views of the spike protein, we were able to identify key binding sites for glycocalyx sugar polymers and discover how these sugars adapt to different spike conformations,” Amaro said. “It’s exciting, we’ve essentially revealed another secret about how the peak binds to cells to facilitate infection.”

One of the biggest challenges of the current COVID-19 pandemic has been responding to mutations in the virus and emerging variants. New tests must be developed for further modifications to the genetic code of the virus.

But GlycoGrip offers a solution for universal coronavirus testing.

“We are optimistic that GlycoGrip will capture future variants just as easily,” said Freeman.

A patent has been filed for this new technology, and beyond the current pandemic, the team envisions a future in which GlycoGrip can offer cheap and reliable tests for a wide range of viruses.

The article is titled “GlycoGrip: Cell Surface-inspired Universal Sensor for Betacoronaviruses”. The full list of authors includes: Sanghoon Kim, Fiona Kearns, Mia Rosenfeld, Lorenzo Casalino, Micah J. Papanikolas, Carlos Simmerling, Rommie E. Amaro, and Ronit Freeman.

The research was funded by the Research Corporation for Science Advancement Award (COVID Initiative grant # 27350), the North Carolina Policy Collaboratory at the University of North Carolina at Chapel Hill with funding from the North Carolina Coronavirus Relief Fund established. and appropriated by the North Carolina General Assembly, NSF RAPID (DMS-2028758, MCB-2032054), UNC Institute for Convergent Science Director’s Fund, NIH GM132826 and UC San Diego Moores Cancer Center 2020 SARS-COV-2 Seed Grant.


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