Nanotechnological material allows distinguishing the presence of different viruses with more precision and speed than current tests
Do you have a cough, sore throat and congestion? Any one of countless respiratory viruses, including the coronavirus, could be responsible, but which one? Conventional tests can pinpoint some of the likely culprits based on chemical reactions, but the researchers found a better solution: swapping the chemistry for electrical changes detected by nanomaterials.
Using a nanomaterial one atom thick, a device capable of simultaneously detecting the presence of the viruses that cause COVID-19 and the flu can be built, at much lower levels and faster than conventional tests for both. The researchers presented these results at the spring meeting of the American Chemical Society (ACS).
The symptoms of flu and COVID-19 are very similar, making it difficult to tell them apart. The team of researchers at the University of Texas at Austin, in the United States, built a COVID-19 sensor and a flu sensor using graphene, a single layer of carbon atoms arranged in a hexagonal lattice pattern. Its extreme thickness makes graphene very sensitive to any electrical changes in its environment.
Previously, his group presented the design of a graphene-based temporary tattoo that could control blood pressure. To build the infection sensor, the researchers had to make graphene respond to the presence of the viral protein. For this, they turned to the immune system, which produces antibodies perfected to recognize and adhere to specific pathogens. Researchers linked graphene to antibodies against SARS-CoV-2, the virus that causes COVID-19, and against the flu 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.
Detect virus in breath
The researchers lacked the necessary security facilities to use live influenza virus or SARS-CoV-2 to test the sensor, which is about one centimeter square. To replace them, they used proteins from these viruses administered in a fluid that was intended to resemble saliva. Their results indicated that the sensor could not only detect the presence of the proteins, but also 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 virus particles found in breath.
Additionally, 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.
The researchers are working to further improve its performance, for example by expanding the range of viruses it can detect, as well as variants of SARS-CoV-2 such as omicron and delta. While they currently focus on a two-variant design, the test could be tailored to identify even more, they say.
Source: American Chemical Society