Researchers have used graphene — one of the strongest, thinnest known materials — to detect the SARS-CoV-2 virus in laboratory experiments. The discovery has potential applications in the fight against COVID-19 and its variants.
In experiments, researchers combined sheets of graphene — which are more than 1,000 times thinner than a postage stamp — 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. These sheets were also tested in the presence of other coronaviruses like Middle East respiratory syndrome (MERS-CoV).
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 evident in less than five minutes.
Graphene — which has been called a “wonder material” — has unique properties that make it highly versatile, making this type of sensor possible. Graphene is a single-atom-thick material made up of carbon. Carbon atoms are bound by chemical bonds whose elasticity and movement can produce resonant vibrations, also known as phonons, which can be very accurately measured. When a molecule like a SARS-CoV-2 molecule interacts with graphene, it changes these resonant vibrations in a very specific and quantifiable way.
Since the graphene is just one atom thick, a molecule on its surface is relatively enormous and can produce a specific change in its electronic energy. In this experiment, the researchers 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.