As businesses scramble to find ways to make workers and customers feel safe about entering enclosed spaces during a pandemic, several companies have proposed a solution: COVID-19 air monitoring devices.
These devices suck in large quantities of air and trap aerosolized virus particles and anything else that’s present. The contents are then tested for the presence of the novel coronavirus, also known as SARS-CoV-2, which causes COVID-19.
Several companies in the air quality and diagnostics sectors have quickly developed this sort of tech, with various iterations available on the market. The devices can be used anywhere, such as office buildings, airplanes, hospitals, schools and nursing homes, these companies say.
But the devices don’t deliver results in real time—they don’t beep to alert people nearby that the virus has been detected. Instead, the collected samples must be sent to a lab to be analyzed, typically with a method called PCR, or polymerase chain reaction.
This process takes hours. Add to that the logistics of physically transporting the samples to a lab and it could be a day or more before results are available. Still, there’s value in day-old air quality information, say developers of this type of technology.
“It’s not solving everything about COVID-19,” says Milan Patel, CEO of PathogenDx, a DNA-based testing company. But it does enable businesses to spot the presence of the virus without relying on people to self-report, and brings peace of mind to everyone involved, he says. “If you’re going into a building, wouldn’t it be great to know that they’re doing environmental monitoring?” Patel says.
PathogenDx this year developed an airborne SARS-CoV-2 detection system by combining its DNA testing capability with an air sampler from Bertin Instruments. The gooseneck-shaped instrument uses a cyclonic vortex that draws in a high volume of air and traps any particles inside in a liquid. Once the sample is collected, it must be sent to a PathogenDx lab, where it goes through a two-step PCR process. This amplifies the virus’s genetic code so that it can be detected. Adding a second step to the process improves the test’s sensitivity, Patel says. (PCR is also the gold standard for general human testing of COVID-19.)
Patel says he envisions the device proving particularly useful on airplanes, in large office buildings and health care facilities. On an airplane, for example, if the device picks up the presence of the virus during a flight, the airline can let passengers on that plane know that they were potentially exposed, he says. Or if the test comes back negative for the flight, the airline can “know that they didn’t just infect 267 passengers,” says Patel.
In large office buildings, daily air sampling can give building managers a tool for early detection of the virus. As soon as the tests start coming back positive, the office managers could ask employees to work from home for a couple of weeks. Hospitals could use the device to track trends, identify trouble spots, and alert patients and staff of exposures.
Considering that many carriers of the virus don’t know they have it, or may be reluctant to report positive test results to every business they’ve visited, air monitoring could alert people to potential exposures in a way that contact tracing can’t.
Other companies globally are putting forth their iterations on SARS-CoV-2 air monitoring. Sartorius in Göttingen, Germany says its device was used to analyze the air in two hospitals in Wuhan, China. (Results: The concentration of the virus in isolation wards and ventilated patient rooms was very low, but was higher in the toilet areas used by the patients.)
Assured Bio Labs in Oak Ridge, Tennessee markets its air monitoring device as a way to help the American workforce get back to business. InnovaPrep in Missouri offers an air sampling kit called the Bobcat, and Eurofins Scientific in Luxembourg touts labs worldwide that can analyze such samples.
But none of the commercially available tests can offer real-time results. That’s something that Jing Wang and Guangyu Qiu at the Swiss Federal Institute of Technology (ETH Zurich) and Swiss Federal Laboratories for Materials Science and Technology, or Empa, are working on.
They’ve come up with a plasmonic photothermal biosensor that can detect the presence of SARS-CoV-2 without the need for PCR. Qiu, a sensor engineer and postdoc at ETH Zurich and Empa, says that with some more work, the device could provide results within 15 minutes to an hour. “We’re trying to simplify it to a lab on a chip,” says Qiu.
The device combines an optical sensor and a photothermal component that harness localized surface plasmon resonance sensing transduction and the plasmonic photothermal effect. But before the device can be tested in the real world, the researchers must find a way, on-board the device, to separate the virus’s genetic material from its membrane. Qiu says he hopes to resolve this and have a prototype ready to test by the end of the year.