NRI develops test to visually detect Covid-19 in 10 mins

A team of US scientists led by an Indian-origin researcher has developed an experimental diagnostic test for Covid-19 that can visually detect the presence of coronavirus in 10 minutes.

Scientists from the University of Maryland School of Medicine developed the test that uses a simple assay containing plasmonic gold nanoparticles to detect a colour change when the virus is present.

The test does not require the use of any advanced laboratory techniques, such as those commonly used to amplify DNA, for analysis.

"Based on our preliminary results, we believe this promising new test may detect RNA material from the virus as early as the first day of infection. Additional studies are needed, however, to confirm whether this is indeed the case," said study leader Dipanjan Pan, professor of diagnostic radiology and nuclear medicine and pediatrics.

Once a nasal swab or saliva sample is obtained from a patient, the RNA is extracted from the sample via a simple process that takes about 10 minutes. The test uses a highly specific molecule attached to the gold nanoparticles to detect a particular protein.

This protein is part of the genetic sequence that is unique to the novel coronavirus. When the biosensor binds to the virus's gene sequence, the gold nanoparticles respond by turning the liquid reagent from purple to blue.

"The accuracy of any Covid-19 test is based on being able to reliably detect any virus. This means it does not give a false negative result if the virus actually is present, nor a false positive result if the virus is not present," informed Dr Pan.

Many of the diagnostic tests currently on the market cannot detect the virus until several days after infection. For this reason, they have a significant rate of false negative results.

Dr Pan now plans to have a pre-submission meeting with the US Food and Drug Administration (FDA) within the next month to discuss requirements for getting an emergency use authorisation for the test.

"This RNA-based test appears to be very promising in terms of detecting the virus," said study co-author Matthew Frieman. Others in Dr Pan's team were research scientist Parikshit Moitra, research fellow Maha Alafeef, along with research fellow Ketan Dighe from the University of Maryland, Baltimore County.

The authors published their work in the American Chemical Society's nanotechnology journal ACS Nano..