ATLANTA--Georgia State University researchers have received a one-year, $200,000 rapid response grant from the National Science Foundation to develop a tool to detect the presence of SARS-CoV-2, the virus causing the COVID-19 pandemic.
Technology being developed by chemistry professor Gangli Wang in collaboration with assistant biology professor Mukesh Kumar is anticipated to provide several benefits, including fast turnaround time and greatly decreased false negative outcomes.
"It's extremely challenging to detect a single virus, which represents the earliest or most sensitive detection possible," said Wang. "When you take a pregnancy test, for example, you collect a urine sample first thing in the morning because that's when the biomarkers are more concentrated. But we don't want to wait till the virus grows in our bodies before we test for it."
Testing methods now require a multi-step process to purify and amplify, or grow, the sample so even trace amounts of the virus can be detected. This treatment process is expensive and time consuming, contributing to the lag time in obtaining test results. It is also error prone, increasing the chance of false negative results.
"The more you have to do to the sample, the more likely you are to end up with errors," Kumar said. "There are so many places where things can go wrong."
Wang's simplified testing method uses electrochemistry to bypass the need for sample treatment or amplification by using a sensor to detect genetic sequences specific to SARS-CoV-2.
"We're essentially using the virus RNA molecule as a switch," said Wang. "If the RNA sequence is present, it interacts with our sensor and switches on the circuit so that electrons flow to create current signal, like water flows after a faucet is switched on. If the RNA isn't present, the switch remains off."
The method allows scientists and clinicians to detect tiny amounts of the virus in a sample. It also provides the quantity of a patient sample's viral load by measuring the intensity of these interactions, or how quickly they occur.
"When small amounts of the virus are present," Wang said. "it may also take longer for the RNA sequence to interact with the sensor, so the amount of time it takes for the switch to turn on will give us some information about the abundance of the virus in a sample."
Wang initially developed the tool to detect microRNAs, molecules whose concentration can fluctuate in the presence of diseases such as cancer. The technology is not specific to a particular RNA sequence, though, and can be adapted to detect SARS-CoV-2 or any mutations of the virus that may emerge, paving the way for future point-of-use applications that go beyond the novel coronavirus.
"Wth the rest methodology already developed, all we would need to do is redesign the recognition sequence," Wang said.
Using the grant, Wang, Kumar and their teams will demonstrate the tool works and establish a calibration profile so scientists and lab technicians can determine the quantity of the virus present. They hope the test could be used on its own or as a cross-check in combination with what's now available to detect SARS-CoV-2. If everything works perfectly, Wang said, it could eventually be used at home, like a glucose monitor.