The protein is an an olfactory receptor that responds to the smell of human sweat, that the scientists have embedded within an artificial cell membrane.
Using a mobile robot mounted with the sensor, whenever it ‘smells’ human sweat, the robot will become active. See image above.
The scientists say that the ability to react to human sweat may one day play a role in helping to search for and rescue people during disaster relief operations.
Although not the first group to create an odor detecting sensor, the University of Tokyo team is the first to use a living creature’s organics.
It’s also more compact, odor sensitive, and selective in its olfactory selectiveness—it smells what it smells, and that is human sweat.
Led by Professor Takeuchi Shoji (surname first) at the University of Tokyo Institute of Industrial Science, Researcher Misawa Nobuo (surname first) at Kanagawa Academy of Science and Technology (KAST), and their collaborators at Sumitomo Chemical, the research team embedded the olfactory receptor—a membrane protein found in the antenna of a mosquito, which responds to human sweat odor—into an artificial cell membrane mimicking nature by having a lipid bilayer, which was formed using a method built on the scientists’ earlier research.
The olfactory receptor used in the current study responds only to a substance called octenol, an odor component of human sweat, and changes the membrane’s conductivity, or the ease with which electricity passes through it. A mosquito identifies human odor by detecting this change in electrical current.
The researchers installed the sensor—the membrane embedded with the mosquito protein—into a small wireless device and mounted it on a locomotive robot; they succeeded in demonstrating that when octenol was released in the air around the robot, it responded by moving.
Next up, the research team is looking to develop practical applications for the sensor to help rescuers search for the missing in disasters and other situations when visual confirmation is difficult… like when someone is buried under rubble after a building collapse…
“Using the olfactory receptors of insects apart from the mosquito presents possibilities for applying them to detect illegal drugs and explosives,” says Takeuchi. “The life of the sensor currently stands at about one hour; we are aiming to extend this to around half a day.”
The current findings are based on results obtained from a project commissioned by the New Energy and Industrial Technology Development Organization (NEDO), Japan. This research was carried out as a collaboration among the University of Tokyo, KAST, and Sumitomo Chemical. The research outcome was delivered as an oral presentation during the MicroTAS 2016 international conference held in Ireland in October of 2016.