Researchers at the University of Illinois Chicago have developed a graphene-based sensor that can rapidly detect the SARS-CoV-2 virus. The system includes graphene sheets that are coupled with an antibody against the viral spike protein. When viral particles bind to the antibodies, they change the vibrational properties of the graphene sheets, and the researchers can measure this using Raman spectroscopy. The test takes less than five minutes, and could provide another useful tool in the fight against COVID-19.
While vaccination programs are picking up speed, the global fight against COVID-19 is still a long way from over. Even in countries that were early leaders in the vaccination rollout, such as the UK, new variants threaten to derail plans to loosen restrictions. In many regions of the world, vaccination campaigns have yet to begin in earnest, with COVID-19 still raging through the population.
Rapid and reliable testing is still an unmet need, with new technologies welcome. This latest device exploits the vibrational properties of graphene to detect COVID-19. “We have been developing graphene sensors for many years. In the past, we have built detectors for cancer cells and ALS. It is hard to imagine a more pressing application than to help stem the spread of the current pandemic,” said Vikas Berry, a researcher involved in the study, in a UIC press release. “There is a clear need in society for better ways to quickly and accurately detect COVID and its variants, and this research has the potential to make a real difference. The modified sensor is highly sensitive and selective for COVID, and it is fast and inexpensive.”
The system is based on the vibrations of the carbon atoms making up graphene sheets, which can be measured usi ngRaman spectroscopy. By incorporating antibodies against the SARS-CoV-2 virus into graphene, the researchers transformed it into a viral sensor, and observed obvious vibrational differences when the graphene was exposed to an artificial saliva sample containing the virus. Conversely, the sensor did not react in the same way to a blank sample, or other coronaviruses, such as the causative virus for Middle East respiratory syndrome, demonstrating its selectivity.
“Graphene is just one atom thick, so a molecule on its surface is relatively enormous and can produce a specific change in its electronic energy,” said Berry. “In this experiment, we modified graphene with an antibody and, in essence, calibrated it to react only with the SARS-CoV-2 spike protein. Using this method, graphene could similarly be used to detect COVID-19 variants.”