Graphene sheets form sensor to rapidly detect COVID-19

Researchers at the University of Illinois Chicago have used sheets of graphene to quickly detect COVID-19 in laboratory experiments, an advance that could potentially detect variants of the virus.

graphene sensor
The white rectangle represents the substrate with graphene functionalized with SARS-CoV-2 antibody (shown in yellow). When this graphene detector interacts with the virus’ spike protein in a COVID-positive sample, its atomic vibration frequency changes (Image: Vikas Berry)

According to UIC, the researchers combined sheets of graphene with an antibody designed to target the spike protein on the coronavirus. They then measured the atomic-level vibrations of these graphene sheets when exposed to COVID-positive and COVID-negative samples in artificial saliva. The sheets were also tested in the presence of other coronaviruses, such as Middle East respiratory syndrome.

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The UIC researchers found that the vibrations of the antibody-coupled graphene sheet changed when treated with a COVID-positive sample, but not when treated with a COVID-negative sample or with other coronaviruses. Vibrational changes measured with a Raman spectrometer were reportedly evident in under five minutes.

Their findings are published in the journal ACS Nano.

“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, professor and head of chemical engineering at the UIC College of Engineering and senior author of the paper. “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.”

“This project has been an amazingly novel response to the need and demand for detection of viruses, quickly and accurately,” said study co-author Garrett Lindemann, a researcher with Carbon Advanced Materials and Products, or CAMP. “The development of this technology as a clinical testing device has many advantages over the currently deployed and used tests.”

Carbon atoms in graphene are bound by chemical bonds whose elasticity and movement can produce resonant vibrations (phonons), which can be measured very accurately. When a molecule such as a SARS-CoV-2 molecule interacts with graphene, it changes these resonant vibrations in a very specific and quantifiable way.

“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,” Berry said in a statement. “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.”

A provisional patent has been submitted based on this work.