If it confirms its performance, the new test will significantly reduce the analysis time while quantifying the viral load.
The new Nobel Prize thanks to Crispr Jennifer Doudna, who together with Emmanuelle Charpentier has just won the 2020 chemistry prize for the development of the DNA editing method, also puts a hand in coronavirus diagnostics . His team has developed a new rapid test that, using Crispr, is able to identify the genetic material of Sars-Cov-2 in biological samples in a few minutes , without the need for many reagents and complicated machinery. And it also provides an indication of the viral load .
Crispr against coronavirus
Tests to detect coronavirus based on Crispr-Cas methodology are nothing new in this pandemic. In essence, they work like this: a complementary guide rna is created to a specific sequence of the viral genome; when the guide rna is paired with the rna of the virus it activates the Cas protein that cuts all those sequences triggering a particular molecule which, hit by a laser pulse, emits a fluorescent signal .
Not bad, but to be sure to find the genome of the virus until now we had to amplify it – an operation that does not reduce the time much compared to the classic swab test and does not even solve the problem related to the availability of reagents.
The new quick test
This new test, on the other hand, has on its side the fact of using more guide rna to increase sensitivity . In practice, the researchers explain in the preprint available on medRxiv , there is no need to amplify the genetic material of the virus because by making several guide rna work in tandem, it is possible to identify the virus even at low concentrations . If a guide RNA works with 100,000 viral particles per microliter of solution, two guide RNAs identify a positive sample with 100 viral particles per microliter.
As reported by Science Magazine Melanie Ott, coordinator of the study together with Doudna, the sensitivity of the conventional molecular test (which also detects 1 viral particle per microliter) is not reached, but the result is obtained in just 5 minutes .
The new test would also have another advantage : by not amplifying, the quantity of the genetic material of the virus in the sample is not altered, giving the possibility to estimate the quantity of virus present. In fact, researchers argue that the intensity of the fluorescent signal is proportional to the viral load when a sample is positive.
The rapid test with Crispr has not yet passed the scrutiny of the scientific community, but, if it is confirmed valid, it could very quickly reach commercialization