New Methodology to Detect SARS-CoV-2 That Produces Reliable Results More Quickly Could Be a Game-Changer

Researchers at the Binghamton University (Binghamton, NY, USA) have developed a nucleic acid sensor that has the potential to speed sample turn-around time while maintaining the sensitivity and specificity parameters that make molecular testing powerful.

Methods to detect SARS-CoV-2, the virus that causes COVID-19, come in two types. The first detects the virus protein or “antigen,” the basis of the rapid tests found at local stores, with results typically coming back in around 15 minutes. The second type are molecular tests designed to detect virus nucleic acid, which can take anywhere from one to three days to return results. In the very specific and sensitive molecular tests, specimens must be shipped to testing labs, where the samples are then processed and analyzed by technicians with specialized training. As a result, they’re considered by scientists as the gold standard for testing due to their reliability, although their long wait time makes them cumbersome for patients.

The nucleic acid sensor developed by the researchers is called an E-beacon and may lead to faster, more accurate test for coronavirus. Enzymatic beacons are engineered “bioconjugates” with two key components: a light-generating enzyme and a DNA probe. The components are stitched together via a recently-patented method. In the E-beacons prepared for SARS-CoV-2, the DNA probe recognizes a specific sequence in the virus’ spike gene; that recognition event in turn causes the light output from the attached enzyme to increase. The more virus nucleic acid in a sample, the brighter the light signal from the enzyme component of the E-beacon.

E-beacons can provide positive or negative results more rapidly than molecular tests, and without the expensive instrumentation required by polymerase chain reaction (PCR) based testing. The E-beacon experiments haven’t yet been done outside the lab, which is the likely next step. However, its applications could be a game-changer. For instance, users can access a walk-up, automated testing device that somewhat resembles a vending machine to deposit a testing swab into a collection port. The molecular tests would then run autonomously within the machine, sending out the results via cell phone in about two hours. E-beacons represent an attractive alternative to the current testing methods, and not just for SARS-CoV-2. Because of their modular design, they can be reconfigured easily for detecting other viral or bacterial pathogens.

“We focused on cutting down the wait time for molecular testing. We developed a nucleic acid sensor - we call it an E-beacon - that has the potential to speed sample turn-around time while maintaining the sensitivity and specificity parameters that make molecular testing so powerful,” said Brian Callahan, Binghamton University Associate Professor of Chemistry. “As of now, our E-beacons appear to be just as specific and even more sensitive than detection methods used in current SARS-CoV-2 molecular tests.”

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