A biosensor currently in development by researchers normally focused on air pollution could provide a way to quickly and accurately detect the COVID-19 virus in the air.
The Swiss-based research group from Empa, ETH Zurich, and Zurich University Hospital had already been working on virus and bacteria monitoring technology before the COVID-19 outbreak, but pivoted in January to focus specifically on detecting the SARS-CoV-2 virus that causes the respiratory disease.
While the technology likely won’t replace diagnostic tests such as the reverse transcription polymerase chain reaction (RT-PCR) options most labs are using, the new biosensor could offer a faster alternative. It could also be used in crowded public locations such as hospitals or train stations to measure the concentration of the virus in the air in real time, according to a press release.
“Biosensors are ideal for providing an alternative and reliable solution to clinical diagnosis, real-time detection, and continuous monitoring,” the researchers say in their recently-published study related to the new technology.
How the coronavirus-detecting biosensor works
According to the Empa press release, the optical biosensor is made up of gold nanostructures known as “gold nanoislands” on a glass substrate. “Artificially produced DNA receptors that match specific RNA sequences of the SARS-CoV-2 [virus] are grafted onto the nanoislands,” the release says. The researchers then use the optical phenomenon known as localized surface plasmon resonance to detect the presence of the virus.
In addition, a temperature increase caused by the plasmonic photothermal effect ensures only SARS-CoV-2 RNA strands can bind to the DNA receptors, avoiding inaccurate test results.
Though the biosensor isn’t yet ready to be used for monitoring the COVID-19 virus in the environment, researchers have so far tested how well it can distinguish between the SARS-CoV-2 virus and its close relative, SARS-CoV, which caused an outbreak in 2003.
"Tests showed that the sensor can clearly distinguish between the very similar RNA sequences of the two viruses," says Empa researcher Jing Wang in the press release.
Once further work is completed, the sensor could also be adapted to detect other viruses and contain outbreaks before they become pandemics.
Other work with biosensors for detecting COVID-19
The Empa team isn’t the only one using biosensors to detect SARS-CoV-2. Researchers in Korea are also working on such a device involving a sheet of graphene with high electric conductivity. This field-effect transistor biosensor, also described in ACS Nano, detects the virus in nasopharyngeal swab samples through a change in electrical current.
While it does not require sample pretreatment or labeling and is faster than RT-PCR tests, it is less sensitive. However, the researchers say in an American Chemical Society press release that using different materials could solve these sensitivity issues.
In Canada, researchers at the University of Calgary are testing a handheld biosensor that could be used by people at home to determine whether they have the virus. The unit would then wirelessly send the results to local health officials within minutes, according to a university press release.
While the team has received funding from the Canadian Institutes of Health Research to develop their microfluidic electrochemical nano-biosensors, the technology is still months away from full production. The team aims to first test the tool with an avian coronavirus to determine how well it can detect the one that causes COVID-19.
“Combining the RNA tests with home-based point-of-care serological assays, we will differentiate between healthy people, those who are symptomatic with COVID-19 and need to remain isolated, and those who were infected but have fully recovered and are able to leave isolation and get back to work,” explains Amir Sanati-Nezhad, PhD, an assistant professor at the University of Calgary’s Schulich School of Engineering, in the release.
On the commercial side, San Diego-based graphene manufacturer Grolltex, Inc. is collaborating with the Sanford Burnham Prebys Medical Discovery Institute to create a graphene-based point-of-care testing platform for COVID-19.
Like the other sensing options, the Grolltex device, which includes a handheld reader and disposable plastic testing chips, provides results in minutes. While the science side of the device is complete, the company is currently looking for a partner to help them scale up and produce it.
“We’re still a small start-up so we’re looking for a financial or resource partner to help us get this up to volume and in the right hands. We know we’re in one of the best locations in the US for an effort like this so once we make the partnering connections, the ramp [up] will be fast,” Grolltex co-founder and CEO Jeff Draa tells the San Diego Business Journal.
Based on the work done by researchers and their partners so far, it seems biosensors are a promising option to quickly and safely detect the COVID-19 virus and control its spread.