A group of scientists has designed a CRISPR-based COVID-19 diagnostic test that is capable of generating a result in 15 to 30 minutes with the aid of a smartphone camera. Compared to the standard polymerase chain reaction (PCR) tests used, the CRISPR Cas13 protein test eliminates the need for DNA conversion and amplification steps in the analysis. According to Jennifer Doudna, a Berkeley professor and one of the corecipients of the 2020 Nobel Prize in Chemistry for the discovery of CRISPR-Cas gene editing, this kind of technology will be “helpful in places that have limited access to testing.”
To achieve this, CRISPR Cas13 proteins identify specific segments of the SARS-CoV-2 RNA, cleave the RNA, and then deploy an RNA probe that is triggered to turn fluorescent when split. When the viral RNA activates the Cas13 proteins, it will begin to split the probe, which is then detected by a smartphone camera thanks to the fluorescence. According to the research, the rate at which the sample brightens is related to the number of virus particles in the sample.
The PCR tests typically convert the SARS-CoV-2 RNA into DNA before “amplifying” or creating copies of the segments to make them easily identifiable. While relatively reliable, these tests often cannot keep up with the current rate of testing demanded to combat the pandemic.
“Recent models of SARS-CoV-2 suggest that frequent testing with a fast turnaround time is what we need to overcome the current pandemic,” shared Dr. Melanie Ott, director of the Gladstone Institute of Virology. “We hope that with increased testing, we can begin to reopen economies and protect the most vulnerable populations.”
The team will be developing the technology further to accommodate the detection of other viral diseases such as influenza, HIV/AIDS, or even the common cold. The researchers are currently working on packaging the test to be used in clinics and point-of-care environments. They are hoping that the technology can eventually be developed into devices that can be used by anyone at home.
“The eventual goal is to have a personal device, like a mobile phone, that is able to detect a range of different viral infections and quickly determine whether you have a common cold or SARS-CoV-2 or influenza,” said Daniel Fletcher, one of the researchers and a professor of bioengineering at Berkeley. “That possibility now exists, and further collaboration between engineers, biologists and clinicians is needed to make that a reality.”
Read the full study at https://www.cell.com/cell/fulltext/S0092-8674(20)31623-8.