They've already shown that their sugar-coated COVID-19 test strip can identify three variants of the virus. In the next few weeks, the National Science Foundation-funded scientists will see how GlycoGrip fares against Omicron.
Researchers from the University of North Carolina at Chapel Hill and University of California San Diego took advantage of the coronavirus' sweet tooth in designing GlycoGrip. The team's findings, published December 15 in ACS Central Science, demonstrated that GlycoGrip could detect wild type SARS-CoV-2 spike as well as the Alpha, Beta, and Delta variants
"We have turned the tables on the virus by using the same sugar coat it uses to infect cells," said UNC researcher Ronit Freeman, an associate professor in the Department of Applied Physical Sciences. "We are optimistic that GlycoGrip will capture future variants just as easily."
The rapid self-test is inspired by the biology of epithelial cells -- those 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; it's this sugar net the virus exploits to cause infection.
In the test, a droplet of biofluid containing the virus, such as saliva, is placed on one end of a strip and flows along the surface. When the fluid reaches a sugar-coated patch, the virus indulges 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 tapped into nature to reimagine viral diagnostics," Freeman said.
To better understand how these sugar polymers bind the virus, Freeman connected with Rommie Amaro, a biochemist at the University of California San Diego and co-corresponding study author.
Amaro and her team developed simulations that helped explain the mechanics behind how and why the cell-anchored sugars bind the viral spike protein, which the virus uses to infect host cells.
"We were able to identify key binding sites for the glycocalyx sugar polymers and unlock how these sugars adapt to different spike conformations," Amaro said. "We essentially revealed another secret of how spike binds cells to facilitate infection."
A patent has been filed for this new technology and looking beyond the current pandemic, the team envision a future in which GlycoGrip can offer cheap and reliable testing for a wide range of viruses.
Read the study: https://pubs.acs.org/doi/10.1021/acscentsci.1c01080