ENose - electronic nose technology

Electronic noses can come in contact with chemical odors that are harmful to humans. In addition, the researchers also tried to build an electronic nose to send into space.

The smell of fragrant pizza coming from the stove is enough to make you salivate. The human nose is a living receptor that responds to the chemicals in pizza giving it a characteristic aroma. The brain recognizes the combination of almost instant smells. However, if compared to dogs, the nose is not as sensitive.

Chemists have tried to design special receptors - called electronic noses - that can help people smell better . Electronic noses can come in contact with chemical odors that are harmful to humans. In addition, the researchers also tried to build an electronic nose to send into space.

Color layout templates

Scientists have designed and built electronic nose devices for over 20 years. Such a device is like a computer chip coated with sophisticated small dots. Each dot contains a chemical dye. Ken Suslick, a chemist at Illinois State University at Urbana-Champaign, said: 'We use between 20 and 36 different dyes that change color according to the chemical it contacts'.

Some dyes are made of color-changing materials to denote an acid or base chemical. Similar to when you use litmus paper - it contains dye that turns red when exposed to acid, for example lemon juice and blue with base material, for example soda water. The electronic nose can detect liquid or solid chemicals. The color composition is the same as the chemical mark. Each composition is unique for a single odor or mixed smell.

Connect small dots

In order to know what a small color dots layout means, the scientist needs to compare it to the data warehouse that contains all symbols that characterize many different smells. The human brain also has such a data warehouse. We get used to all kinds of smells for life. When our nose senses an odor, the brain connects it to the smell you already know. When the brain performs contrast, it will recognize an odor.

To build his electronic nose database, Suslick exposed the chip to a variety of substances and recorded small color dots.

Amy Ryan , a chemist working in Nasa's Jet Propulsion Laboratory in Pasadena and Enose (Photo: nasatech)

Chemicals in space

Electronic nose can also alert people to danger. For example, on a space ship or in the International Space Station (ISS), a leaked chemical could be a problem for the spacecraft or crew. So it's important to detect such leaks. NASA is trying to design and test such an electronic nose, called ENose.

They hope that ENose will one day be inside the space ship to monitor chemical leaks. ENose used a set of 4 chips, each with 8 sensing bodies. Each receptor includes a thin plastic film that shrinks and stretches according to the airborne compound. The reaction of plastic film forms a layout pattern. Like the human brain, ENose is programmed to recognize this layout and smell.

After being installed in the space ship, Enose will operate continuously 24 hours / day and 7 days / week, monitoring the air to quickly detect dangerous substances, such as mercury .

NASA had previously tested the first version of an electronic nose device within 6 days on a spaceship in 1998. Currently, NASA is urgently preparing another 6-month trial on ISS, contingent. However, in the present, the electronic nose is still not competitive with the dog's nose, and the way of perfecting the electronic nose is still far away .

Dien San