Check in five minutes
According to experts, in the complex of measures to stop the pandemic, it is important to have a test system for rapid screening of a large number of people in crowded places. After all, even in the absence of symptoms, a person can be a carrier of COVID-19 and infect others. Express diagnostics will allow identifying and isolating these people until they cease to pose a danger to others. A group of researchers working at the American Chemical Society has developed a prototype breath test that can reliably and accurately diagnose COVID-19 even in asymptomatic carriers in less than 5 minutes.
Currently, the gold standard for COVID-19 testing is the reverse transcription polymerase chain reaction (RT-PCR) method, which is slow, requires a smear from the nasopharynx and must be performed in the laboratory. The rapid antigen test is performed much faster, but has a higher percentage of false negative and false positive results. Scientists have also developed respiratory tests to detect COVID-19, which determine the concentrations of volatile organic compounds exhaled by coronavirus infected, but most of them require cumbersome and complex analysis tools. Xing Yi Ling and his colleagues undertook to develop a fast, convenient and accurate test that would be suitable for screening a large number of people on the spot.
The researchers created a portable tester containing a chip with three Raman scattering sensors (SERS) attached to silver nanoparticles. When a person breathes into the device for 10 seconds, the compounds in the exhaled air interact chemically with the sensors. The researchers then load the chip into a portable Raman spectrometer, which characterizes the formed compounds based on changes in the molecular vibrations of the SERS sensors.
They tested the test system on 501 people in hospitals and airports in Singapore, in whom PCR showed a negative (85.2%), positive with symptoms (8.6%) or positive asymptomatic (6.2%) result for coronavirus. The new method yielded 3.8% false negative and 0.1% false positive results, which is comparable to PCR tests, but it could be performed on-site in less than 5 minutes.
Researchers hope that the rapid respiratory test will replenish the arsenal of tools to combat the COVID-19 pandemic.
Article by S.X.Leong et al. Noninvasive and Point-of-Care Surface-Enhanced Raman Scattering (SERS)-Based Breathalyzer for Mass Screening of Coronavirus Disease 2019 (COVID-19) under 5 min is published in the journal ACS Nano.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on the materials of the American Chemical Society: Quick COVID breathalyzer could allow mass screening in public places.