By Bill Levesque
It is crucial to get a test result for a pathogen quickly, lest someone continue in their daily lives infecting others. Delays in testing have undoubtedly exacerbated the COVID-19 pandemic.
Unfortunately, the most accurate COVID-19 test often takes 24 hours or longer to return results from a lab.
At-home test kits offer results in minutes but are far less accurate.
However, researchers at the University of Florida (UF) have helped to develop a COVID-19 testing device that can detect coronavirus infection in as little as 30 seconds. The testing device is just as sensitive and accurate as a PCR or polymerase chain reaction test, the gold standard of testing. UF researchers are now working with scientists at National Yang Ming Chiao Tung University in Taiwan.
Researchers say the device could transform public health officials’ ability to quickly detect and respond to the coronavirus or the next pandemic.
UF has entered into a licensing agreement with a New Jersey company, Houndstoothe Analytics. They hope to ultimately manufacture and sell the device, not just to medical professionals but also to consumers.
According to a recent peer-reviewed study published by UF researchers, the device boasts a 90 percent accuracy rating and comparable sensitivity to that of a PCR test.
“There is nothing available like it,” said Josephine Esquivel-Upshaw, D.M.D., a professor in the UF College of Dentistry’s Department of Restorative Dental Sciences and a member of the research team that developed the device. “It’s true point of care. It’s access to care. We think it will revolutionize diagnostics.”
The device is not yet approved by the U.S. Food and Drug Administration. Researchers say they must first ensure that test results are not abstracted by cross-contamination. This analysis is ongoing as researchers work to identify other pathogens that might be found in the mouth and saliva that could precipitate contagion, such as other coronaviruses, staph infections, the flu, pneumonia and 20 others.
The hand-held apparatus is powered by a 9-volt battery and uses an inexpensive test strip, similar to those used in blood glucose meters. Coronavirus antibodies are attached to a gold-plated film at the tip of the device. The test strip is placed on the tongue to collect a tiny sample of saliva. The test strip is then inserted into a reader connected to a circuit board that houses the “brains” of the device.
If someone is infected, the coronavirus in the saliva binds with the antibodies and begins to dart around as they are prodded by two electrical pulses produced by a unique transistor. A higher concentration of coronavirus changes the electrical conductance of the sample which alters the voltage of the electrical pulses.
The voltage signal is amplified a million times and converted to a numerical value, which is essentially the sample’s electrochemical fingerprint. That value indicates a positive or negative result. A low value indicates a higher proportion of the virus detected within the sample. Researchers say the device’s ability to quantify viral and antibody load makes it especially useful for clinical purposes.
Esquivel-Upshaw confirms that the product can be constructed for less than $50. In contrast, PCR test equipment can cost thousands.
The research team also is studying its ability to detect specific proteins that could be used to diagnose other illnesses, including cancer, a heart attack and immune health.
Fan Ren, Ph.D., a distinguished professor in the Herbert Wertheim College of Engineering’s Department of Chemical Engineering and his team have been developing semiconductor-based sensor devices for nonmedical purposes long before COVID-19.
Ren notes that he finds inspiration for his work in the recent death of his wife which was unrelated to COVID-19. [SL1] He connects his grief to the mourning of the rest of the world amidst the COVID-19 pandemic.
“Almost a million people have died of COVID” in the United States, Ren said. “Those are so many tragedies. Old people. Young people. You name it. I said, ‘No, that’s it.’ That is too much.”
He told of several institutions working on devices that use a field effect transistor (FET) like that found in the COVID-19 testing device his team is developing. Even so, those devices are made for one-time use. The sample is applied directly to the FET, so the transistor is no longer usable and must be discarded.
Ren states that the expendable nature of those devices makes them expensive and impractical for mass testing.
The UF device is unique in its structure due to the separation of the transistor from the sample, like blood glucose meters that use test strips to collect a drop of blood after a lancet pierces a finger. This innovation sets the device apart from the rest in both affordability and ease of use.
Ren proposes that the device could be a crucial advancement in testing for venues with large crowds, such as concerts, sporting events or classrooms. Researchers say the unit would also potentially provide access to inexpensive and accurate testing in rural areas and developing nations.
Researchers also discussed the limitless opportunities for personal usage of the device such as parties, events, and other gatherings.
“Yes or no. You’re infected or not infected. You get the answer right away,” said Ren.
Reprinted from Today’s FDA, 2022 May/June issue. Visit floridadental.org/publications to view Today’s FDA archives.
Beyond the Bite 