An ‘Electronic Nose’ to Sniff Out COVID-19

A masked student in a lab coat and gloves examines an electronic device. — Postdoc Scott Zhang at work in the Johnson lab. Their current device is more than 90% sensitive and specific for COVID-19, but the researchers are hoping to improve the device’s accuracy through a better understanding of what specific chemicals give patients with COVID-19 a unique odor profile. (Photo: Eric Sucar, University Communications)

Even as COVID-19 vaccines are being rolled out across the country, the numerous challenges posed by the pandemic won’t all be solved immediately. Because herd immunity will take some time to reach and the vaccine has not yet been approved for some groups, such as children under 16 years of age, the coming months will see a continued need for tools to rapidly track the disease using real-time community monitoring.

A team of Penn researchers is working on a new “electronic nose” that could help track the spread of COVID-19. Led by physicist Charlie Johnson, the project, which was recently awarded a $2 million grant from the NIH, aims to develop rapid and scalable handheld devices that could spot people with COVID-19 based on the disease’s unique odor profile.

Dogs and devices that can detect diseases

Long before “coronavirus” entered into the vernacular, Johnson was collaborating with Cynthia Otto, director of the Penn Vet Working Dog Center, and Monell Chemical Senses Center’s George Preti to diagnose diseases using odor. Diseases are known to alter a number of physical processes, including body odors, and the goal of the collaboration was to develop new ways to detect the volatile organic compounds (VOCs) that were unique to ovarian cancer.

A tangle of circuit boards, wires and tubes that make up the researcher's "electronic nose." — The next step is to scale down the current device, and the researchers are aiming to develop a prototype for testing on patients within the next year.

Since 2012, the researchers have been developing new ways to diagnose early-stage ovarian cancer. Otto trained dogs to recognize blood plasma samples from patients with ovarian cancer using their acute sense of smell. Preti, who passed away last March, was looking for the specific VOCs that gave ovarian cancer a unique odor. Johnson developed a sensor array, an electronic version of the dog’s nose, made of carbon nanotubes interwoven with single-stranded DNA. This device binds to VOCs and can determine samples that came from patients with ovarian cancer.

Last spring, as the pandemic’s threat became increasingly apparent, Johnson and Otto shifted their efforts to see if they could train their disease-detecting devices and dogs to spot patients with COVID-19.

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