U.S. engineers have designed a small tabletop device that can detect SARS-CoV-2 from a saliva sample in about an hour. In a new study, they showed that the diagnostic is just as accurate as the PCR tests now used.
The device can also be used to detect specific viral mutations linked to some of the SARS-CoV-2 variants that are now circulating. This result can also be obtained within an hour, potentially making it much easier to track different variants of the virus, especially in regions that don’t have access to genetic sequencing facilities.
Researchers demonstrated that the platform can be programmed to detect new variants that emerge, and that they could repurpose it quite quickly. In this study, they targeted the U.K., South African, and Brazilian variants, but the diagnostic platform could adapt to address the Delta variant and other ones that are emerging.
The goal was to create an entirely self-contained diagnostic that requires no other equipment. Essentially the patient spits into this device, and then you push down a plunger and you get an answer an hour later. The researchers designed the device so that it can have up to four modules that each look for a different target RNA sequence. The original module contains RNA guide strands that detect any strain of SARS-CoV-2. Other modules are specific to mutations associated with some of the variants that have arisen in the past year.
The Delta variant was not yet widespread when the researchers performed this study, but because the system is already built, they say it should be straightforward to design a new module to detect that variant. The system could also be easily programmed to monitor for new mutations that could make the virus more infectious.
The researchers first tested their device with human saliva spiked with synthetic SARS-CoV-2 RNA sequences, and then with about 50 samples from patients who had tested positive for the virus. They found that the device was just as accurate as the gold standard PCR tests now used, which require nasal swabs and take more time and significantly more hardware and sample handling to yield results.
The device produces a fluorescent readout that can be seen with the naked eye, and the researchers also designed a smartphone app that can read the results and send them to public health departments for easier tracking.
The new diagnostic, which relies on CRISPR technology, can be assembled for about $15, but those costs could come down significantly if the devices were produced at scale. Researchers believe their device could be produced at a cost as low as $2 to $3 per device. They envision that this kind of diagnostic could be useful either for people who want to be able to test at home or in health care centres in areas without widespread access to PCR testing or genetic sequencing of SARS-CoV-2 variants.
The ability to detect and track these variants is essential to effective public health, but unfortunately, variants are currently diagnosed only by nucleic acid sequencing at specialised epidemiological centres that are scarce even in resource-rich nations.
U.S. researchers have been developing new technologies to mitigate COVID-19, such as face masks that can detect COVID-19 infection. As reported by OpenGov Asia, U.S. Engineers have designed a novel face mask that can diagnose the wearer with COVID-19 within about 90 minutes. The masks are embedded with tiny, disposable sensors that can be fitted into other face masks and could also be adapted to detect other viruses, including influenza, Ebola, and Zika.
