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But now scientists and entrepreneurs are redoubling their efforts to recreate the sense of smell in compact devices that detect and analyze odors in much the same way that cameras now recognize our faces and microphones our words. In pursuit of these cutting-edge devices—which could use odors to detect diseases like cancer or Covid-19, locate hidden explosives, or decipher our moods and behavior—some companies are taking advantage of advances in synthetic biology and genetic engineering. Others take advantage of advances in artificial intelligence.
“It’s absolutely a growing field,” says Andreas Mershin, an odor sensor researcher at the Massachusetts Institute of Technology. “We realize that there is a whole world of molecules that we are blind to.” He calls the field an “unexplored gold mine.”
The search for better olfactory sensors is challenging because odors are composed of many different chemicals and because animals’ olfactory receptors—specialized cells in the nose that recognize odor molecules—are remarkably diverse. For example, humans have three types of receptors for color vision, but hundreds of different olfactory receptors.
Among the most futuristic devices are those that contain living cells designed to respond to specific odor components. Koniku Inc., a startup in San Rafael, Calif., is now using bioengineered nerve cells as the basis for sensors capable of detecting the subtle odors of explosives. The cells contain proteins designed to detect so-called volatile organic compounds, carbon-containing substances that seep into the air from a variety of sources, including food, paint, drinks, bodies and unexploded bombs.
“We’re designing olfactory cyborgs,” says Osh Agabi, the company’s founder and CEO. He says the firm is working with Airbus Americas to develop sensors for use at airports to detect packages and luggage containing explosives. The goal is not to replace bombs, according to Bruce Coole, head of aviation security programs at Airbus Americas, there are sniffer dogs and other security measures now in place but to be expanded.
In recent tests at San Francisco International Airport, Konik’s prototype bomb-sniffing device identified pieces of planted luggage known to contain explosives, according to Dr. Agabi with 97% accuracy. In separate tests, Konik’s sensors matched the ability of trained dogs to detect explosives, he says, adding that the company is also developing sensors for use in healthcare and other industries.
“When you look at the scale of how many compounds or how many odors affect human life that haven’t been cataloged yet, we’ve barely scratched the surface,” says Dr. Agabi.
Aromyx Corp., a startup in Mountain View, Calif., is also using cells to create odor sensors. But rather than selling equipment, it offers food and wine producers laboratory services to help them better understand the specific odor molecules that drive consumer preferences. The company combines consumer survey data on people’s likes and dislikes with how bioengineered odor-detecting cells respond to certain odor molecules to create preference profiles.
“The value is not in the sensor, but in the data,” says Josh Silverman, CEO of Aromyx.
Mershin Dr. MIT focuses on medical applications of scent technology. Inspired by dogs that have shown the ability to sniff out malignant tumors in humans, he is working on an artificial intelligence odor detection system that would detect prostate cancer.
In 2021, the team of Dr. Mershiny published results showing that their system matched the ability of trained dogs to detect prostate cancer in the urine of patients with the disease. Since then, the team has increased the software’s accuracy to more than 90%, says Dr. Mershin and adds that the system is more reliable than the well-known prostate-specific antigen (PSA) blood test, which can lead to false positive diagnoses. . Only 25% of men who undergo a prostate biopsy after a suspicious PSA test later develop cancer, according to the National Cancer Institute.
Olfaction experts warn that a number of scientific and technical challenges need to be overcome before high-tech odor detectors are ready for widespread market penetration. For systems that use living cells, it will be important to monitor how often the device needs to be replaced and how accuracy accumulates over long time frames, they say.
“The idea is great. The problem is the implementation,” says Nathan Lewis, a chemist and olfactory sensor developer at the California Institute of Technology.
Scientists and data rights experts say sophisticated molecular tracking has emerged, for example. turning cell phones into what some experts call “sniffer phones” capable of detecting health problems—raises uncomfortable privacy questions. The smells our bodies constantly emit contain clues about our health and personal choices, including the products we use and the foods we eat, as well as our drinking and smoking habits, etc. According to legal experts, the collection and analysis of human olfactory data could affect for example, some insurance coverage and also employment.
“We’re not prepared for the consequences,” says David Carroll, an associate professor of media design at Parsons School of Design and a data rights activist. “It will raise deep, deep ethical issues.”