July 26, 2021

a “precise, rapid and portable” test for the identification of COVID-19 and the screening of mutant strains

Juan Carlos Izpisua, extraordinary professor of Developmental Biology at the Catholic University of Murcia (UCAM) and professor at the Salk Gene Expression Laboratory, in the United States, is the main author of a work, published in Med, in which it is described a new test, called NIRVANA, which simultaneously detects and sequences COVID-19 and any of its variants, the flu virus and other viruses, in a few minutes, with portable technology, as reported by the university center in a press release .

© UCAM

Izpisua has explained, in the aforementioned informative note, that it is “a method of detection and surveillance of viruses that does not require an expensive infrastructure, as in other cases, but we achieve, with a quick and portable test, the same as other slower and more expensive methods ”. The project is funded by UCAM and the Seneca Foundation, the Murcia Region Science and Technology Agency.

Doing tests that can detect COVID-19 quickly in the population, they continue, is “key to stopping its spread. On the other hand, it is essential to monitor new variants of the virus, some of which could respond differently to treatments or vaccines ”. Currently, the standard test to determine if a patient has the disease is to perform a PCR to identify the genetic material of the virus. However, “if the test is negative, we don’t get any information about the cause of the patient’s symptoms, unless they do additional PCR tests for other viruses. And if the sample is positive for SARS-CoV-2, we do not know with which variant of COVID-19 the patient is infected, unless other much longer and more expensive sequencing tests are carried out, ”explains Estrella Núñez, Vice-Rector for Research from UCAM and co-author of the study.

The PCR technique uses temperature cycles to separate the DNA strands and copy them repeatedly to be able to visualize them; RPA, for its part, uses proteins, rather than temperature changes, to achieve the same thing. This technology makes it possible to copy longer stretches of DNA and probe multiple genes at the same time. “We quickly realized that we could use this technique not only to detect SARS-CoV-2, but also other viruses at the same time,” says Mo Li, co-leader of the research group.

In the article, the researchers describe the design of a small, portable device, NIRVANA, based on the RPA method, which can analyze 96 samples at the same time. This tool can simultaneously test COVID-19, influenza, human adenovirus, and non-SARS-CoV-2 human coronavirus samples. In just 15 minutes, the device starts giving positive and negative results, and in three hours it finishes the results of all 96 samples, including the sequences of five regions of SARS-CoV-2 that are particularly prone to mutations that lead to new ones. variants.

NIRVANA has been tested in positive samples for coronavirus, to determine COVID-19 and wastewater that could contain this virus and others. In all cases, they highlight, the test was able to correctly detect which viruses were present and, in addition, the sequencing data allowed to delimit the origin of SARS-CoV-2 in positive cases, differentiating strains from China, Europe or Africa, for example. “The design of this device is very flexible, so it is not limited only to the examples that we have tested so far, we can easily adapt it to detect other pathogens, even something new and emerging,” stresses Li.

Given the small size and portability of NIRVANA, it could be used to quickly identify viruses in companies, schools, universities or airports, provided by UCAM in the aforementioned statement, or to monitor wastewater and detect the presence of new viruses. “The COVID-19 pandemic has brought two important lessons to the table: first, conduct massive tests quickly, and second, learn the variants of the virus. Our NIRVANA method provides a promising solution to these two challenges not only for the current pandemic, but also for possible future ones ”, concludes Izpisua.