With the Delta variant wreaking havoc on unvaccinated populations and COVID-19 cases spiking around the world, the pandemic is far from over. Despite the impressively fast development of SARS-CoV-2 diagnostic tests over the last year and a half, the vast majority of patient samples must still be sent to a lab for processing, which slows down the pace of COVID-19 case tracking. If a sample is to be tested for a specific variant of the virus, it must be genetically sequenced, which takes even more time and resources.
Now, researchers at the Wyss Institute for Biologically Inspired Engineering at Harvard University, the Massachusetts Institute of Technology (MIT), and several Boston-area hospitals have created an inexpensive, CRISPR-based diagnostic test that allows users to test themselves for SARS-CoV-2 and multiple variants of the virus using a sample of their saliva at home, with no extra instrumentation needed.
The diagnostic device, called Minimally Instrumented SHERLOCK (miSHERLOCK), is easy to use and provides results that can be read and verified by an accompanying smartphone app within one hour. It successfully distinguished between three different variants of SARS-CoV-2 in experiments, and can be rapidly reconfigured to detect additional variants like Delta. The device can be assembled using a 3D printer and commonly available components for about $15, and re-using the hardware brings the cost of individual assays down to $6 each.
"miSHERLOCK eliminates the need to transport patient samples to a centralized testing location and greatly simplifies the sample preparation steps, giving patients and doctors a faster, more accurate picture of individual and community health, which is critical during an evolving pandemic," said co-first author Helena de Puig, Ph.D., a Postdoctoral Fellow at the Wyss Institute and MIT.
The diagnostic device is described in a paper published today in Science Advances.
From supply chain to SHERLOCK
As an Instructor in Pediatrics at Boston Children's Hospital with a specialization in infectious diseases, co-first author Rose Lee, M.D. has been working on the front lines of the COVID-19 pandemic for over a year. Her experiences in the clinic provided inspiration for the project that would ultimately become miSHERLOCK.
"Simple things that used to be ubiquitous in the hospital, like nasopharyngeal swabs, were suddenly hard to get, so routine sample processing procedures were disrupted, which is a big problem in a pandemic setting," said Lee, who is also a Visiting Fellow at the Wyss Institute. "Our team's motivation for this project was to eliminate these bottlenecks and provide accurate diagnostics for COVID-19 with less reliance on global supply chains, and could also accurately detect the variants that were starting to emerge."