The new salivary test for COVID was developed by scientists at Harvard University and MIT, ed is able to determine which variant of COVID-19 you have, using 3D printed components and costing just $ 2 (about € 1.71) per device.
The details of the diagnostic device, along with models for 3D printing, They were published online. The team behind the test says they want to create something simple, which could, for example, “Be built by a doctor in Zimbabwe and 3D printed inside their facilities”. It runs on batteries and gives results in an hour.
The test can successfully identify Alpha, Beta, and Gamma variants in a patient’s saliva, and the researchers claim that they are developing the device to detect the Delta variant.
If new variants emerge, the team could perform a strain-specific saliva test in just two weeks. The likelihood of this happening, experts previously said, it depends on the number of people who get infected. As more countries relax restrictions, more people are likely to be infected. This means there will be more chances of the virus changing in a way that affects COVID-19 disease, creating a disturbing new variant.
All four research co-authors released the project to explain everything there is to know about the new COVID-19 variant test.
and how does the salivary test of the COVID-19 variant work?
The test uses the scissors from scientists’ molecular toolbox: technology CRISPR. “CRISPR is a part of the bacterial immune system that evolved to detect and cut DNA,” explained Dr Xiao Tan, one of the first four authors of the research. “For bacteria, it’s a way to defend themselves. What we have done is co-opt it to detect the things that interest us “.
Unlike some CRISPR technologies, the scissors used in the skewer test aren’t just one-cut wonders. Called SHERLOCK, which stands for “high sensitivity reporter specific enzyme release” can actually detect the presence of COVID-19.
The researchers worked with Dr Jim Collins, one of the co-founders of SHERLOCK technology, to design their device. When SHERLOCK finds a particular spike protein specific to the variant in question, it activates an enzyme, which continues to create the fluorescent light that indicates the test is positive, said Devora Najjar, co-first author. “So only if CRISPR finds the [virus COVID-19] it will begin to release fluorescence. Otherwise, you will not get any fluorescence. “
Getting the saliva test done is simple and no training is required, the researchers said. First, spit into the sample preparation chamber. Turn on the heat and wait three to six minutes for the saliva to diffuse through the filter.
Then, take the filter and move it to the reaction chamber column. Push down to add saliva to three small pipettes, each containing SHERLOCK technology specific for the different variants.
An hour later, you will see fluorescent light, bad news, or no light at all. Even a supplied smartphone app can read the result.
Salivary testing uses minimal tools, which is why the researchers called it miSHERLOCK. Compared to home PCR testing, the miSHERLOCK device is simpler and cheaper, say the researchers.
“I’m not sure how this works in the UK, but in the US, just shipping samples like the ones that have been FDA approved costs $ 120,” Tan said.
Partially recyclable salivary test
For the miSHERLOCK test, a device costs around $ 15. “But if you reuse some of the components, you can actually cut them down to maybe $ 6,” explained Tan. “Then we figured out how much it would cost to a commercial supplier and you could probably cut this down to $ 2-3 per test.”
“This is for all the parts you need to get an answer right away, without having to wait 72 hours of turnaround for the shipping process.”
Can saliva testing detect the Delta variant?
In the research, published in Science Advances, the team tested the device against the Alpha, Beta and Gamma variants. They say they are working now to target the Delta variant.
“When we started this project a few months ago, we were looking for strains that are no longer the main variants of interest,” said Najjar. “It talks about the rapidly changing nature of the pandemic and how we need to create systems that are just as agile as the virus.”
The tubes inside the reaction chamber are called assays and can be individually designed to target a very small and specific part of a genetic code.
“You can think of the device almost like a miniature coffee machine with several coffee pods. Except that we have designed every pod, every test, to contain these CRISPR enzymes, each specific to the gene we are looking for “, explained Dr. Rose Lee, another early authors of the study and an infectious disease specialist at Boston Children’s Hospital.
The team has currently developed a ‘pod’ that can generally detect the COVID gene and others that detect specific genes for spike proteins on COVID variants.
Each test takes about two weeks to create, so each time DNA for a new variant is identified, the team could produce a new ‘pod’ 14 days later.
Why do we need to know which variant a person has?
As the virus mutated, it became more contagious, and further variants could prove more deadly.
“Knowing which variant you have could be significantly relevant, because it changes the way we think about the therapies we could use for the patient, such as antibody treatment,” said Lee.
In Delta’s case, a recently published study suggested the strain was resistant to neutralization by different types of antibodies and that a single dose of Pfizer or AstraZeneca’s coronavirus vaccine had “A barely perceptible inhibitory effect on the Delta variant”, although two doses neutralized the virus.
It also helps the countries to keep track of variants currently worrying in a population.
“Variant monitoring is usually performed by sequencing very few samples and then extrapolating from there to get an idea of the entire population”, explained Dr Helena de Puig, co-author.
Although the miSHERLOCK device does not perform sequencing, which means that cannot detect a previously unknown strain, provides data that can be used to track the spread of known variants.
This research now needs large-scale production and approval from bodies such as the FDA before it can be mass marketed. The team pointed out that their laboratory does not have the ability to sell devices and get FDA approval.
“Production capacity and FDA approval are usually required to commercialize a test”de Puig said. “We would love to see this academic work used in clinics and, if there are manufacturing facilities that would like to develop it, we would be very, very happy to help them.”
The team hopes this can be used all over the world to help populations manage the spread of COVID-19.
“It’s very easy for us to make the components, the only thing that needs to change is the small part that aims for a particular peak on the variant,” said Tan.
“In fact, the device doesn’t even need to be limited to COVID. There are many other infectious diseases in which there are viral particles in the saliva that could be used for this as well. We haven’t necessarily tested them, but there’s no reason why it wouldn’t work. “