Now, a tiny electronic nose to detect toxic hazards

Scientists at the Massachusetts Institute of Technology (MIT) have engineered an electronic nose that can help detect hazards like carbon monoxide, harmful industrial solvents, and explosives.

Washington, November 10 : Scientists at the Massachusetts Institute of Technology (MIT) have engineered an electronic nose that can help detect hazards like carbon monoxide, harmful industrial solvents, and explosives.

Lead researcher Harry Tuller has revealed that the tiny nose uses a novel inkjet printing method to print thin sensor films onto a microchip, a process that could eventually allow for mass production of highly sensitive gas detectors.

"Mass production would be an enormous breakthrough for this kind of gas sensing technology," said Tuller, a professor in the Department of Materials Science and Engineering (MSE), who presented the research at the Composites at Lake Louise Conference in Alberta, Canada.

The prototype sensor consists of thin layers of hollow spheres made of the ceramic material barium carbonate, which can detect a range of gases.

Tuller says that using a specialized inkjet print head, tiny droplets of barium carbonate or other gas-sensitive materials can be rapidly deposited onto a surface, in any pattern the researchers design.

Tuller says that the low-cost detector can be used in a variety of settings, from an industrial workplace to an air-conditioning system to a car's exhaust system.

"There are many reasons why it's important to monitor our chemical environment," he said.

He also said that for a sensor to be useful, it should be able to distinguish between gases. For example, he added, a sensor at an airport would need to know the difference between a toxic chemical and perfume.

Tuller said that sensors could be provided with the ability to distinguish between gases by equipping them with an array of films, which respond differently to different gases. He said that it would be similar to the way the human sense of smell works.

"The way we distinguish between coffee's and fish's odour is not that we have one sensor designed to detect coffee and one designed to detect fish, but our nose contains arrays of sensors sensitive to various chemicals. Over time, we train ourselves to know that a certain distribution of vapors corresponds to coffee," he said.

The researchers used a programmable Hewlett-Packard inkjet print head, located in the MIT Laboratory of Organic Optics and Electronics, in their study. The special gas-sensitive "inks" used by them were optimised for printing by Amy Leung, an MIT sophomore in chemical engineering.

In future studies, the researchers hope to create large arrays of gas-sensitive films with controlled three-dimensional shapes and morphologies.

ANI