A new generation of molecular testing for Covid-19

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A team from ESPCI Paris- PSL supported by the City of Paris, has developed a field test, both fast and reliable, for Covid-19. The so-called COVIDISC is based on a microfluidics device developed by the Tabeling’s research group at ESPCI, that has already proven its effectiveness on several diseases such as Zika or dengue fever. The test has been adapted for Covid-19, and has both a high sensitivity and specificity.
This new test relies on the most recent molecular technologies compared to the existing PCR technology, which is 37 years old. The key device is simple to use, cheap, portable and can be kept at room temperature. It produces reliable results in less than an hour and could be produced on a large scale.

Lisa Dehove

Since 2014, Patrick Tabeling’s research group has been collaborating with the Pasteur Institute on the development of a diagnostic test using molecular biology and capillary forces inside paper networks to detect viral RNA, i.e a virus genetic footprint inside clinical samples (blood, saliva…). With the support of the city of Paris, the team (Patrick Tabeling, Etienne Coz, Pierre Garneret and Elian Martin), combining physicists, biologists and engineers, started adapting the system to COVID-19 in early February.
Each virus has in its genome some specific areas. Designing a set of primers, which detects these areas and amplifies them, is a way to specifically identify the pathogen.
“The exceptional results we obtained with the experiments performed with Pierre, Etienne and Elian are very encouraging”, highlights Patrick Tabeling. We managed to detect very low amounts of viral charges, close to what can be detected with PCR technology. In addition, the test is also selective, which means that it detects specifically COVID-19, and not other pathogens.

A clever system, suitable for diagnosis

The device works in two steps:
First the virus RNA is extracted on a membrane (from a saliva or nasal swab). Then the genetic material is amplified at constant temperature (using the LAMP method), on a treated substrate. Finally the amplification products are detected. The isothermal nature of the reaction is crucial, since it requires much simpler and cheaper instruments than the PCR method; which has been the reference until now.

“The key to this invention lies in the coupling between an excellent fluid management provided by microfluidics, and the use of the LAMP technique- invented 20 years after PCR- which produces a system much more adapted to a simplified diagnosis”, adds P. Tabeling. Indeed, the system is entirely portable, with an analysis taking around one hour, and the team is currently working on different steps to further reduce this analysis time.

Lisa Dehove

Toward industry

Commercialization services at PSL University also support the project towards its future marketing. The team is already in touch with a manufacturer to prepare a large scale production of the COVIDISCS, while optimising the analysis and reading systems.
The goal could be to use the tests in medical practices and small laboratories. The city of Paris has already ordered 1000 tests and some prototypes.

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