Researchers hope CRISPR gene-editing technology can yield rapid at-home COVID-19 test

Researchers in the U.S. are using the gene-editing technology known as CRISPR to devise a COVID-19 diagnostic test that they say could be quick, cheap and only slightly more complicated than a pregnancy test.

Piyush Jain, a biomolecular scientist and assistant professor at the University of Florida, says the technique could be used to detect the RNA — a molecule related to DNA — of SARS-CoV-2, which causes COVID-19, in human saliva.

"Imagine there's a twig in a forest, which represents the coronavirus RNA, and we want to find it. It's going to be hard, right? So we use CRISPR to find that twig in the entire forest," he told Day 6.

Jain detailed the research, which has not yet been clinically validated or reviewed by independent scientists, in a post for The Conversation.

The test, which is only a proof of concept, would display its results on a paper strip in roughly 45 to 60 minutes, he said.

"If you see a band in the positive position, then you know that you have coronavirus. If you see ... a band in the negative position, then you know that you're coronavirus negative," he said.

The U.S. Food and Drug Administration has greenlit several COVID-19 diagnostic tests to help make up for test shortages in the United States.

According to Nature Magazine, more than 60 diagnostic tests were given emergency-use authorizations, including a CRISPR-based version developed by Sherlock Biosciences, a bioengineering company co-founded by "CRISPR pioneer" Feng Zhang.

Unapproved medical products can be granted an emergency use authorization, or EUA, on a temporary basis "when there are no adequate, approved, and available alternatives," according to the FDA website.

None of the tests have received clearance for at-home use, according to Nature.

Sherlock CEO Rahul Dhanda told U.S.-based health-care industry site Med City News that the company is working to scale production of the test kit, and hopes to be able to test hundreds of patients a day in hospital settings by the summer.

Jain says the at-home test kit they are envisioning has several working parts and would require six steps to complete, including spitting saliva into a tube and then combining it with a chemical reagent that will eventually detect the SARS-CoV2 RNA when submerged into warm water.

It could help avoid the need to go to a testing centre, or to mail a swab sample to a lab and wait days for the result, he said.

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He hopes an eventual testing kit will be available for five dollars for the public, then eventually at around $2 US per kit.

Research into this CRISPR COVID-19 test is still in its early stages, however, and will have to go through several stages of approval by the FDA before it becomes available to the public.

"The first stage will be to get an approval for a lab-based test and then get an approval for a hospital to do the test, and then eventually get an approval for the home-based test kit," explained Jain.

"So we have a lot of regulatory hurdles in our way," he said, adding that he expects it would take months before it is available to use at home.

CRISPR's role in COVID research

Most CRISPR-related research into COVID-19 is concerned with developing rapid-response tests to detect the virus, according to Dr. Janet Rossant, a senior scientist at the Hospital for Sick Children in Toronto.

Rossant has been a pioneer of new techniques for manipulating the genes of mice, and is one of a handful of scientists in Canada to use CRISPR on non-human embryos.

Her team is one of several around the world working on modifying mouse genomes that would allow them to be used for COVID-19-related animal trials.

Mice genes are different enough from humans' that they cannot be infected with the coronavirus, Rossant explained. By modifying the genes with CRISPR, a "humanized mouse" could be used for COVID-related animal trials, she said.

"This mouse could then be used to study the mechanisms of infection, test drugs and vaccines for safety and efficacy before going into human trials," she said.

She pointed to preliminary research published this week in Cell Host & Microbe submitted by Chinese researchers that found the model of a "humanized mouse" could be "a useful tool for studying SARS-CoV-2 transmission and pathogenesis."

Jain says his team is working with "multiple potential commercial partners" and hopes that once the test kit is approved for general use, they can assemble up to one million kits a day.

But he also stressed the importance of many separate teams developing similar tests in addition to his own.

"Having different companies and technologies work side-by-side on solving the major problem of COVID-19 testing will help the world addressing the crisis, increasing the total number of testing kits available every day," he said.

Written by Jonathan Ore. Produced by Yamri Taddese.

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