{"id":42043,"date":"2021-08-06T18:07:23","date_gmt":"2021-08-06T22:07:23","guid":{"rendered":"https:\/\/sciencebusiness.technewslit.com\/?p=42043"},"modified":"2021-08-06T18:07:23","modified_gmt":"2021-08-06T22:07:23","slug":"portable-testing-device-ids-covid-19-variants","status":"publish","type":"post","link":"https:\/\/technewslit.com\/sciencebusiness\/?p=42043","title":{"rendered":"Portable Testing Device IDs Covid-19 Variants"},"content":{"rendered":"
\"miSherlock<\/a>
Minimally instrumented Sherlock device (Wyss Institiute – Harvard Univ. and MIT)<\/figcaption><\/figure>\n

6 Aug. 2021. A low-cost device is being developed that analyzes saliva samples for SARS-CoV-2 viral mutations, and returns results in about one hour. The device is the work of a team from the Wyss Institute for Biologically Inspired Engineering<\/a> at Harvard University and Massachusetts Institute of Technology<\/a>, and described in today’s issue of the journal Science Advances<\/em><\/a>.<\/p>\n

Since the start of the pandemic, the SARS-CoV-2 virus responsible for Covid-19 infections mutated into several variations, including the delta variant, now the dominant strain in the U.S. and other parts of the world. Most of today’s rapid tests for the SARS-CoV-2 virus are designed to detect the presence any SARS-CoV-2 virus, not specific variants. To identify those variants, nasal swab or other specimens must be genetically sequenced, which in most cases means sending a sample to a remote lab for analysis, with results returned many hours or days later.<\/p>\n

Researchers from the biomedical engineering lab of James Collins, affiliated with the Wyss Institute<\/a> and MIT<\/a>, are seeking a fast, reliable, low-cost, and easy-to-use device to detect precise Covid-19 variants. The team of engineers and medical practitioners from Boston-area hospitals adapted a technology using the gene-editing technique Crispr<\/a>, short for clustered regularly interspaced short palindromic repeats. Crispr is a genome-editing process based on bacterial defense mechanisms that use RNA to identify and monitor precise locations in DNA.<\/p>\n

The researchers’ used an application of Crispr developed at the Broad Institute, affiliated with MIT and Harvard, called Sherlock<\/a>, short for specific high-sensitivity enzymatic reporter unlocking. Sherlock uses Crispr editing enzymes that seek out specific genetic sequences in a specimen sample, and if detected in the sample, bind to and cut the RNA in nearby locations. Sherlock adds a reporter sequence to the RNA, a specific piece of synthetic RNA, which also gets cut by the editing enzyme, releasing a signal identifying the presence of the original target sequence. Those signals can be converted into a bioluminescent visual display that can appear on an everyday material like paper and at room temperature, or captured electronically.<\/p>\n

High sensitivity and specificity<\/h4>\n

The battery-powered device, known as miSherlock, short for minimally instrumented Sherlock, captures an individual saliva sample, which is heated to 95 degrees C (203 F). After three to six minutes, the heated saliva sample is wicked into a filter, which the user transfers to a separate analysis chamber. The filter sample is pushed into the analysis chamber with a plunger that mixes the sample with stabilizing chemicals, dithiothreitol<\/a> and egtazic acid<\/a>, to prevent enzymes in saliva from damaging RNA in the sample. That RNA is then extracted through a membrane.<\/p>\n

After extraction, the sample RNA is mixed with freeze-dried Crispr chemicals activated by water in sealed packets. After about 55 minutes, the user can view any change in color indicating the presence of SARS-Cov-2 viral RNA in the sample. The researchers tested the miSherlock device with saliva samples from 27 Covid-19 infected patients, and 21 healthy individuals, and compared the results to conventional RT-PCR tests for SARS-CoV-2. The results show miSherlock returns results with 96 percent true-positive sensitivity and 95 percent true-negative specificity. Further tests show the device can accurately detect the three known variants at the time: B.1.1.7, B.1.351, and P.1, now identified as alpha, beta, and gamma respectively. The team is extending the technology to also detect the delta variant.<\/p>\n

A major advantage of miSherlock is its ease of manufacture, with a 3-D printer, and its low cost. The researchers say the device in the study costs $15.00 to produce, but by reusing some its parts, the cost can be lowered to $11.00. Mass production can reduce the unit cost further to as low as $3.00.<\/p>\n

“We knew that variant tracking was going to be incredibly important when evaluating the long-term effects of Covid-19 on local and global communities,” says Collins in a Wyss Institute statement<\/a>, “so we pushed ourselves to create a truly decentralized, flexible, user-friendly diagnostic platform. By solving the sample prep problem, we\u2019ve ensured that this device is virtually ready for consumers to use as-is, and we\u2019re excited to work with industrial partners to make it commercially available.”<\/p>\n

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