A nanotechnological material makes it possible to distinguish the presence of different viruses with greater precision and speed than current tests

Do you have a cough, sore throat, and congestion? Any of countless respiratory viruses, including the coronavirus, could be responsible, but which one? Conventional tests can identify some of the likely culprits based on chemical reactions, but researchers have found a better solution: replace the chemistry with electrical changes detected by nanomaterials.

Using a nanomaterial one atom thick, it is possible to build a device that can simultaneously detect the presence of the viruses that cause COVID-19 and influenza, at much lower levels and faster than conventional tests for both. The researchers presented these findings at the American Chemical Society’s (ACS) spring meeting.

The symptoms of flu and COVID-19 are very similar, making it difficult to tell them apart. The team of researchers from the University of Texas in Austin, USA, built a COVID-19 sensor and a flu sensor using graphene, a single layer of carbon atoms arranged in a hexagonal lattice. Its extreme thinness makes graphene very sensitive to any electrical changes in its environment.

Previously, his group presented the design of a graphene-based temporary tattoo that can control blood pressure. To build the infection sensor, the researchers had to make the graphene respond to the presence of the viral protein. To do this, they turned to the immune system, which produces antibodies perfected to recognize and adhere to specific pathogens. Researchers have linked graphene with antibodies against SARS-CoV-2, the virus that causes COVID-19, and against the influenza virus. When a sample from an infected person is placed on the sensor, these antibodies bind to their target proteins, causing a change in the electrical current.

The researchers lacked the safety facilities necessary to use live influenza viruses or SARS-CoV-2 to test the sensor, which is aboutone-centimeterr square. To replace them, they used proteins from these viruses administered in a fluid that was meant to resemble saliva. Their results indicated that the sensor could not only detect the presence of the protein, but could do so when they were present in extremely low amounts. According to Akinwande, this sensitivity suggests that the sensor could be used to detect the much more dispersed viral particles found in the breath.

Also, the sensor worked quickly, returning results within 10 seconds of inserting a sample. By comparison, conventional COVID-19 tests can take minutes or hours, depending on the type, and a double COVID-flu test takes about half an hour to return results.

Researchers are working to further improve its performance, for example by expanding the range of viruses it can detect, as well as SARS-CoV-2 variants such as omicrons and deltas. While they currently focus on a two-variant design, the test could be adapted to identify even more simultaneously, they say.

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