Iowa State University researchers are developing a no-touch, fast-scan test for COVID-19 that relies on applying a sample on a printed resonant sensor on paper that can then be dropped at a collection center or mailed-in to get results.
The entire diagnostic test kit would cost about $1, according to Iowa State, and would allow members of the public to take their own samples. The card could be deposited in an envelope and sealed and the results could even be read electronically without opening the envelope, thereby cutting out the need for medical staff in protective gear. The electronic reader could even potentially text or email the results.
“We’re trying to make it so that no one has to touch the samples,” said Nigel Reuel, an assistant professor of chemical and biological engineering at Iowa State, in a statement.
Reuel and his team are using a one-year Rapid Response Research grant of $200,000 from the National Science Foundation to develop the testing concept. It’s not clear what happens next in the process or when a product might come out of the research.
How it works: the sensor system detects RNA genetic material through toehold switches. The detection system triggers reporter proteins that can change the color of a sensor, or the frequency of the sensor’s signal.
Part of the toehold circuit involves an electrical interface developed by researchers at the University of Toronto and Arizona State University.
The finished product will probably involve multiple layers on thick paper with a top layer used to collect nasal or cough samples, middle layers to contain the toehold switch and bottom layers with a printed, coiled resonant circuit that can be scanned for frequencies that would indicate disease.
If COVID-19 RNA is in the sample, the toehold switch would allow production of proteins that degrade a coating on the circuit, yielding a positive signal. If there’s no virus RNA, there would be no protein production, and no coating degradation and therefore a negative signal.
A toehold switch is a class of RNA with a hairpin loop that is unfolded upon binding with a trigger RNA, which would expose a ribosome binding site and permit interpretation of the reporter protein. Toehold switches were used in detecting RNA from Zika and Ebola viruses.