By Nneka Nwogwugwu
Engineers at MIT and Harvard University 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.
James Collins, the Termeer Professor of Medical Engineering and Science in MIT’s Institute for Medical Engineering and Science (IMES) and Department of Biological Engineering, said “in this study, we targeted the U.K., South African, and Brazilian variants, but you could readily adapt the diagnostic platform to address the Delta variant and other ones that are emerging.”
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 large scale, the researchers say.
The paper’s lead authors are Helena de Puig, a postdoc at Harvard University’s Wyss Institute for Biologically Inspired Engineering; Rose Lee, an instructor in pediatrics at Boston Children’s Hospital and Beth Israel Deaconess Medical Center and a visiting fellow at the Wyss Institute; Devora Najjar, a graduate student in MIT’s Media Lab; and Xiao Tan, a clinical fellow at the Wyss Institute and an instructor in gastroenterology at Massachusetts General Hospital.
The new diagnostic is based on SHERLOCK, a CRISPR-based tool that Collins and others first reported in 2017.
Components of the system include an RNA guide strand that allows detection of specific target RNA sequences, and Cas enzymes that cleave those sequences and produce a fluorescent signal.
All of these molecular components can be freeze-dried for long-term storage and reactivated upon exposure to water.
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.
Source: Scitech Daily