CRISPR and COVID-19: A New Method of Virus Testing
As COVID-19 rose in some of the world’s largest countries — such as the US, India, and Brazil — public health systems are faced huge testing backlogs. From tests that take 24 hours to tests that take several days, this backlog posed a serious problem in getting people tested as quickly and as widely as possible.
However, two women may be changing how we conduct our COVID testing altogether. For the first time in history, two women share the Nobel prize in the sciences. Jennifer Doudna, a U.C. Berkeley professor, and Emmanuelle Charpentier, now the Max Planck Unit director for the Science of Pathogens in Berlin, won for their work on CRISPR-Cas9, a method to edit DNA. CRISPR-Cas9 genetic engineering technology enables scientists to change or remove genes quickly and with great precision. Labs worldwide have redirected their research programs to incorporate this new tool, creating a CRISPR revolution with huge implications across biology and medicine.
Image by Arek Socha.
What is CRISPR?
Genome editing is a group of technologies that give scientists the ability to change an organism's DNA. These technologies allow genetic material to be added, removed, or altered at particular locations within the genome.
CRISPR-Cas-9, is short for clustered regularly interspaced short palindromic repeats and CRISPR-associated protein 9, is one of several approaches to genome editing. This CRISPR-Cas9 system has generated a lot of enthusiasm among the scientific community as it is faster, cheaper, more accurate and more efficient than other existing genome editing methods.
The CRISPR-Cas9 was adapted from a naturally occurring genome editing system in bacteria. Essentially, the bacteria captures snippets of DNA from invading viruses and uses them to create DNA segments, known as CRISPR arrays. These CRISPR arrays allow the bacteria to "remember" the viruses (or closely related ones). Thereafter, if the viruses attack the bacteria again, the bacteria produce RNA segments from the CRISPR arrays to target the viruses' DNA. The bacteria can then use Cas9 or a similar enzyme to cut the DNA apart and disable the virus. The CRISPR-Cas9 system works similarly in the lab, except the researcher conducts the work manually that bacteria do automatically.
CRISPR and COVID-19
Doudna, Charpentier, and their team of California-based researchers utilized this technology alongside a modified mobile phone camera to conduct rapid COVID tests. The test recognizes a sequence of RNA in SARS-CoV-2, the coronavirus that causes COVID-19. In an Oct. 12 publication, researchers reported the test yielded results in five minutes and correctly identified five samples from patients with the coronavirus, a discovery that could solve the issue of under-testing in epidemic-stricken countries. When used with a mobile phone to detect signals generated by the test, the technology could provide a fast, low-cost test outside a laboratory, the researchers have said.
Along with the speed of this new testing method, it can accurately quantify the amount of viral matter that is in each sample. No other test can quantify the level of infection and progression of the disease. This method combined multiple CRISPR strands in tandem, increasing the sensitivity of the test, and making amplification unnecessary. This was the key to the drastic reduction in testing time, from one hour to five minutes. Doudna and her firm are working to further develop this test and make it available to labs and medical providers.