CRISPR unlocks its potential to diagnose Covid-19 within 5 minutes

-Surupa Chakraborty, Amity University Kolkata

A new CRISPR based test that can diagnose the coronavirus infection within few minutes, joins the race of speedy detection after RT-PCR, rapid testing, and FELUDA test. The potent applications of CRISPR have been talked about for many years now. It is best known for its ability to seek out and cut genetic material with unparalleled accuracy. Using this property, the researchers programmed CRISPR to search for specific genetic sequences found only in the SARS-CoV-2 virus.

The study published in the Science journal says that it is an inexpensive diagnostic test that could potentially detect the trace of the viral infection within 5 minutes using minimal lab equipment. Previously developed CRISPR based tests by the team, worked by identifying a 20 base long RNA sequence unique to SARS-CoV-2. The scientists created a ‘guide’ RNA complementary to the target RNA sequence which can bind together in the test solution. This in turn activates the CRISPR/Cas 13 ‘molecular scissors’ which cuts apart any single-stranded RNAs present nearby. These cuts generate fluorescent particles in the solution which emit fluorescent signals when hit by a laser beam. But this required the researchers to first amplify the viral RNA present in the sample, to increase the chances of spotting the signal, thereby, adding to its complexity, time, and cost of the diagnosis.

However, the recently developed novel CRISPR-based diagnostic test is based on multiple guide RNAs that work in unison to increase the sensitivity of the test, without the need of amplifying the viral RNA. The test was developed by a team of researchers, led by Jennifer Doudna, a recipient of the Nobel Prize in Chemistry, 2020, for her co-discovery of CRISPR. The test detected as few as 100,000 viruses per microliter of the solution with a single guide RNA, and 100 viruses per microliter with an additional guide RNA. Among samples taken from Covid-19 patients, it was able to precisely identify a batch of five positive samples within 5 minutes per test.

Also, this test is rendered beneficial in quantifying the viral load in the patients, which can help the doctors in their treatment procedures. A mobile phone-based device can be used to directly interpret the results of the diagnosis, which makes the entire assay portable, compared to bulky lab-based plate readers. Combined with efficient contact tracing, this CRISPR based SARS-CoV-2 easy detection test can thus play a pivotal role in the control of the current pandemic.

Source:

Direct detection of SARS-CoV-2 using CRISPR-Cas13a and a mobile phone. Parinaz Fozouni, Katherine S. Pollard, Joseph L. DeRisi, Jennifer A. Doudna, Daniel A. Melanie Ott, et al., (2020), medRxiv, https://doi.org/10.1101/2020.09.28.20201947

Also read: Soil Microbes Consume Atmospheric Hydrogen

For more articles, visit bioxone.in