So far, the array has been tested in rats, with a version for dogs coming later, Labella says. In the demo video, viewed only by Wired, Canaery scientists use the cane to capture air samples from four different Petri dishes, each containing a different odorant. The wand beeps and sends odor molecules through the tube into a pod that houses the rat with a nose and computer interface. Seconds after the animal smells a stinky smell, the scent information is sent to a phone on the pod. The mobile app displays the names of compounds that smell like animals and quality scores taking into account the accuracy and concentration of the molecule.
Currently, Canaery’s rat prototype can detect arson accelerators and smoke-free powders used in ammunition, as well as ammunition, methamphetamine, cocaine and fentanyl.
In mammals, the nose and brain work together to detect odors. When odor molecules enter the nostrils, they bind to olfactory receptors. Humans have around 450 types of olfactory receptors, while dogs have twice as many olfactory receptors. All odors stimulate different combinations of receptor types and generate unique electrical signals. That signal is sent to the olfactory bulb for processing. Lavella likens the surface of the olfactory bulb to a checkerboard. If there is a smell, the checkerboard will be rectangular in a specific pattern.
Canaery uses AI software to recognize these patterns and associate them with odors. After embedding the array, scientists expose the animals to odors to train the AI model. Lavella says the software can be trained in about three sessions. During these sessions, scientists present animals with more than 20 samples of the same smell. The animals are then exposed to odor again to validate the AI model.
The current array embedded in the demo rat has 128 electrodes that capture neural signals from the olfactory bulb. Researchers at Lawrence Livermore National Laboratory are working on a new array with 767 electrodes to capture more information. “The next generation devices can improve field performance against complex background odors and confounding steam in the air,” says Labella.
Deciphering the smell is not a new effort. Researchers have been working on “E-Nose” technology for detecting odors for the past 40 years. These devices use chemical sensors to convert odor molecules into electrical signals, which are analyzed by pattern recognition systems to identify odor sources. However, these devices historically were able to detect only slight odors.
“We’re looking for a way to help you get started,” said Joel Mainland, an Olfaction researcher at Monell Chemical Senses Center, a non-profit laboratory in Philadelphia.
