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According to foreign media reports, doctors using the new coronavirus detection test can not only diagnose COVID-19 in a few minutes with a wearable device, but also detect other viruses, such as influenza, that can be mistaken for the new coronavirus. At the same time, they can also sequence the virus to provide valuable information for the spread of COVID-19 mutations and mutations. March 31, 2021A research team made up of scientists from multiple institutions described this new test called NIRVANA online in the journal Medicine.
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“This is a virus detection and monitoring method that does not require expensive infrastructure like other methods,” said Juan Carlos Izpisua Belmonte, professor at the Salk Gene Expression Laboratory and corresponding co-author of the study. “We can use a portable test to achieve the same thing that others have done with two or three different test methods and different machines.”
Worldwide, more than 100 million people have been infected with SARS-CoV-2, the virus that causes COVID-19. So far, more than 500,000 Americans have died from COVID-19, an alarming number. Testing the population is the key to stopping the spread of the virus. Furthermore, monitoring the spread of new variants of SARS-CoV-2 is crucial; some of these variants may respond differently to treatment or vaccines.
The current standard method to determine if a nasal swab is positive for COVID-19 is to perform a polymerase chain reaction (PCR) test to detect the genetic material of the SARS-CoV-2 virus. However, if the sample is negative, patients and doctors will not get any information that could cause new coronavirus-like symptoms, unless they use different swab samples and perform separate PCR tests for other viruses. And if the sample is positive for SARS-CoV-2, they won’t know which variant of COVID-19 the patient is infected with unless they run another set of tests; these tests require a large and expensive next-generation gene sequencer.
Last summer, Li Mo, associate professor of biological sciences at the King Abdullah University of Science and Technology in Saudi Arabia, was thinking about how to use his expertise in genetic engineering and nanopore sequencing to combat the COVID-19 pandemic. Li Mo previously worked as a Salk postdoctoral researcher in the Izpisua Belmonte laboratory for 6 years. He wanted to know if a genetic detection method called isothermal recombinase polymerase amplification (RPA) combined with real-time nanopore sequencing would be better than the current one. The COVID-19 test method is more useful, faster, cheaper, and more portable. He worked with Izpisua Belmonte to find the answer.
Unlike PCR, which uses cycles of lower and higher temperatures to separate DNA strands and replicate them, RPA uses proteins to accomplish the same thing in just 20 minutes, rather than temperature changes. This technology allows researchers to copy longer pieces of DNA and probe multiple genes at the same time.
“We quickly realized that we can not only use this technology to detect SARS-CoV-2, but also detect other viruses at the same time,” Li Mo said.
In the new article, Li Mo and Izpisua Belmonte describe a small portable device that can simultaneously analyze 96 samples by detecting RPA. They called the NIRVANA method for “fast isothermal virus amplification nanopore sequencing for near real-time analysis.”
The scientist-designed NIRVANA can simultaneously detect samples of COVID-19, influenza A, human adenovirus, and non-SARS-CoV-2 coronavirus. The researchers report that in just 15 minutes, the device began reporting both positive and negative results. In three hours, the device will finally determine the results of all 96 samples, including the sequence of five regions of SARS-CoV-2, which are particularly prone to accumulating mutations and giving rise to new mutations, such as those found in the Kingdom. United. B.1.1.7 Variation.
Li Mo and Izpisua Belmonte performed the NIRVANA test on 10 samples with known SARS-CoV-2 positive, 60 samples with unknown SARS-CoV-2 status, and urban wastewater samples containing the SARS-COV-2 virus. In all cases, the test can correctly identify which viruses are present. The sequencing data also allowed them to reduce the source of SARS-CoV-2 in positive samples; for example, to distinguish between strains from China and Europe.
“The design of this detection is really flexible, so it is not limited to the examples that we show,” said Li Mo. “We can easily adjust it to deal with another pathogen, or even something new.”
