Researchers have developed a novel device that detects the COVID-19 virus in one minute using just a couple of breaths of exhaled air. The device has the potential to revolutionize the testing process, especially in hospitals and schools and at large-scale social gatherings like concerts or sporting events.
Most people would be familiar with at-home COVID tests, so-called rapid antigen tests or RATs – the pain and sneeze-inducing irritation of swabbing the inside of your nostrils, swishing the mucus-coated swab around in a testing solution, squeezing it onto a test strip and waiting 15 or 20 minutes for a result that may or may not be accurate.
Now, researchers at Washington University in St. Louis have developed a hand-held device that tests for the COVID virus using as little as two exhaled breaths and providing an accurate result in around a minute. It’s an improvement on previously developed breath-analyzing COVID detectors that took three or five minutes to provide results.
“With this test, there are no nasal swabs and no waiting 15 minutes for results, as with home test,” said Rajan Chakrabarty, co-corresponding author of the study. “A person simply blows into a tube in the device, and an electrochemical biosensor detects whether the virus is there. Results are available in about a minute.”
The researchers repurposed a biosensor originally created to test for Alzheimer’s-disease-related amyloid beta protein in mouse brains, swapping out the antibody that tests for amyloid beta for a nanobody derived from llama antibodies that recognizes a protein in the SARS-CoV-2 virus, which causes COVID-19.
The process is simple. A 3D-printed collection device is fitted with a straw, which the user blows into. Aerosols from the user’s breath collect on the biosensor inside the device, which is plugged into a machine that determines whether the user is COVID-positive or not.
The researchers tested the device in a lab first, using three COVID variants: WA1, Delta, and Omicron. They found that its sensitivity was comparable to other electrochemical detection techniques for SARS-Cov-2. They then tested it on eight human patients, six who were COVID-positive and two COVID-negative. After having the patients blow into the device two, four, and eight times, the researchers found that the device was accurate, gave no false negatives and that two exhaled breaths were sufficient for virus detection.
With a production cost of less than US$10 per test, the researchers say that their novel device is not only cost-effective, it’s non-invasive and its use doesn’t require trained personnel. Moreover, it can be adapted to detect a range of respiratory pathogens, including new COVID variants. Currently, the researchers are working on the simultaneous detection of multiple airborne viruses using different specific nanobodies.
This novel device has the potential to revolutionize testing, especially at large gatherings like concerts or sports games that have the risk of becoming ‘superspreader’ events. Instead of going through the lengthy process of at-home testing, this new breathalyzer could rapidly test for COVID upon entry with little to no inconvenience and a great deal of peace of mind.
“It’s a bit like a breathalyzer test that an impaired driver might be given,” said John Cirrito, another of the study’s corresponding authors. “And, for example, if people are in line to enter a hospital, a sports arena or the White House Situation Room, 15-minute nasal swab tests aren’t practical, and PCR tests take even longer. Plus, home tests are about 60% to 70% accurate, and they produce a lot of false negatives. This device will have diagnostic accuracy.”
While initial results are promising, the researchers plan to validate them by conducting a longitudinal clinical study.
The study was published in the journal ACS Sensors.
