A team of researchers from the University of Maryland is developing a portable device to identify different odors throughout an environment.

Funded by a four-year, $2 million grant from the National Science Foundation, the “nose on a chip” project aims to develop a device that uses living cells to detect scents. According to project leader and mechanical engineering professor Elisabeth Smela, creating an artificial nose is important because scent is one of the five senses that technology has yet to replicate.

“On our cellphones we have cameras, we have microphones, we have gyroscopes, we have accelerometers,” Smela said. “We don’t have a nose.”

Once developed, the device could detect spoiled food, drugs and bombs, help diagnose diseases and come in handy for search and rescue purposes, according to Smela.

Working alongside Smela on the project are biology professor Ricardo Araneda, electrical and computer engineering professor Pamela Abshire, computer science professor Abhinav Shrivastava and David Tomblin, who directs the College Park Scholars science, technology and society program.

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The sense of smell is extremely versatile across different species, according to Smela. Birds and insects can sense and seek out specific flowers, hounds can follow scent trails that are hours and days old and humans can detect about 10,000 different odors.

For odors that the human nose and existing technology cannot detect, humans utilize dogs, rats and mice, Smela said.

However, according to project co-lead Abshire, there are limitations to these methods. When humans use animals to track or detect odors, there are no electronic records of that detection, making it difficult to reproduce the results, Abshire said.

But the “nose on a chip” that the researchers are developing could offer many industrial and commercial applications.

“It seems that there can almost be an infinite number of things that it can be applied to when it comes to odor,” Tomblin said.

The perfume industry, for example, could use the device to identify which odors people like in order to fashion those scents into new perfume, Tomblin said.

The device could even potentially help people find compatible friends or romantic partners because one of the major ways humans access their social interactions is through smell, according to Abshire.

Development of the “nose on a chip” took off approximately 10 years ago, when Smela and Abshire partnered with Araneda.

At the time, the team was working with primary cells, or cells taken directly from an animal. But the fragility of these cells hindered their progress.

“The olfactory sensory neurons that we worked with once upon a time were some of the most finicky cells that we’ve ever worked with,” Abshire said. “They were the hardest to keep alive.”

The team decided instead to focus on developing an olfactory sensory neuron cell line to conduct research, Smela said. A cell line is a group of cells that can be propagated indefinitely.

Rather than developing their own cell line, which would have been time-consuming, the team reached out to Japan’s National Agriculture and Food Research Organization in hopes of utilizing one of the organization’s existing cell lines, which were developed from insect cells that could be dried out and then later rehydrated.

Those insect-based cells could be stored and controlled at room temperature and were fairly unaffected by a large range of environmental conditions, making them a good fit for the “nose on a chip” researchers.

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“You want [the device] to just sit on the shelf until you’re ready to use it,” Smela said. “We were very excited about the possibility of having cells that could just sit on a chip until they were ready to be used, and then add water.”

NARO successfully genetically engineered the insect cells to be able to detect scent so they could be used for the project. The organization also added a green fluorescent protein into the insect cells, so that when an odor binds to the receptors in the cells, the cells light up.

According to Smela, the researchers’ current work involves machine learning. The team is analyzing how the odor receptors in the insect cells respond to different airborne scents with the assistance of artificial intelligence.

Once a machine learning interface analyzes how the insect cells’ odor receptors recognize airborne scents, researchers will be able to create devices tailored to identifying specific scents — a possibility Smela said is promising for many fields.

“Animals can detect disease — dogs can detect cancer, insects can detect COVID,” Smela said. “People, maybe in the future, would have at home testing kits for disease.”