The status quo is simply not enough.
In the world of scientific breakthroughs, CRISPR technology is definitely one worth mentioning. The ability to edit genomes has allowed us to find solutions to curing conditions caused by genetic error, create a world of more sustainable agriculture, and with the onset of the pandemic, reform COVID-19 diagnostics.
The current “gold standard” of coronavirus testing is a familiar process known as RT-PCR (reverse transcription polymerase chain reaction), where the viral RNA would be converted to DNA, and amplified for a duration of time until the amplification can be detected by a digital device. But while its accuracy is known to be incredibly high (above 95%), it’s by far one of the most time-consuming and expensive.
- The entire process takes 3 hours, and this doesn’t even include the time it takes for the results to finally make it back to the patient (which can take days)
- The equipment required to run this process is terrifyingly pricy because of how complex the procedure it
- Each test sample requires over $5 USD to go through the process (and considering the number of samples that need to be shuffled through on a daily basis, those costs stack up like crazy)
So all of this combined creates the perfect formula for inaccessibility. And with 36% of the world living in poverty, we know there needs to be a change in the way we go about mass testing.
Detecting COVID through cutting coronavirus RNA.
Using CRISPR has opened a door to a faster and more cost-efficient way of detecting COVID-19 — a method that could be widely accessible and implemented at a global scale. It doesn’t require expensive lab equipment and has the potential to limit the detection time down to just 20 minutes, making it easy to implement in doctor’s offices, schools, airports, and other public facilities.
“It looks like they have a really rock-solid test. It’s really quite elegant.” — Max Wilson, a molecular biologist at the University of California, Santa Barbara
What’s involved — a step by step breakdown
Detecting COVID is not actually detecting the virus, but the specific genetic material inside. And with SARS-CoV-2, it has a unique sequence which can be identified.
The novel test works first by placing a “guide” RNA that is complementary to the DNA sequence we want to target into a Cas13 protein (the viral RNA is converted to DNA). This protein then goes into the sample to identify the real sequence of viral DNA by binding this implanted “guide” RNA. When it’s ready, the CRISPR Cas13 tool snips the DNA it is attached onto which activates a fluorescent enzyme, and it’s this fluorescent signal which is tracked with a digital device. The binded Cas13 protein also happens to chop up nearby pieces of RNA put into the sample containing reporter molecules, which function in an identical way of sending signals that it has found it’s target SARS-CoV-2 sequence.
Omitting the amplification process
These initial CRISPR tests, however, required researchers to first amplify any potential viral RNA before running it through the diagnostic to increase the odds of the Cas13 binding. But this added complexity, time, and a strain on already amplification reagents. So ultimately, the test would be almost redundant.
Fortunately, researchers led by Jennifer Doudna, co-inventor of CRISPR, found a way to tweak CRISPR coronavirus diagnostics so then this amplification process wouldn’t be necessary at all. For months they tested hundreds of guide RNAs to find multiple guides that work in tandem to increase the sensitivity of the test and they eventually found a single guide RNA that could detect as few as 100,000 viruses per microliters of solution. And if they add a second one, the sensitivity can multiply by up to 10,000 times.
While this still isn’t accurate as conventional lab-based tests, which use expensive and bulky machines to be able to detect viruses down to 1 virus per microliter, against the race of time, this new diagnostic shows incredible potential. That 20 minutes compared to several days on end is a huge difference, and we need to move faster than the coronavirus if we want to put an end to the coronavirus.
Moving to the market
Now, the biggest challenge remaining is to figure out how to speed up diagnostic commercialization. Often once ideas are invented, the time it takes between the planning, the validation, the rounds of testing, and finally the process of distributing is tedious, something that isn’t exactly ideal during a global pandemic.
In fact, there are many startups including Sherlock Biosciences and Mammoth Biosciences that are working to make CRISPR-based testing faster, more accurate, and available for purchase for testing facilities. And even though it’s possible that CRISPR diagnostics may not be able to scale up to a global scale in time to aid this outbreak, we know for sure they’re certainly being put under our belt for the next one.
- Ashley
