Scientists say artificial noses not to be sniffed at

German researchers create highly sensitive nanotech nostrils

The prototype artificial nose was not taken as seriously as the scientists had hoped

Physicists at Ludwig-Maximilians-Universität in Munich have have constructed a system of nanostrings that could lead to a highly sensitive artificial nose for detecting pollutants or explosives.

The nano-electromechanical system (or NEMS) involve strings just 100 nanometers thick– 500 times thinner than a human hair – which can be made to resonate.

When coated with the right kind of chemicals, the strings are able to attract a specific kind of molecule, which slows the string's movements.

Stringing along

"By measuring the nano-string's period of oscillation, we could therefore detect chemical substances with molecular precision," explains Quirin Unterreithmeier, author of the study. "Ideally, you would have several thousand strings sitting on a chip the size of a fingernail, each one recognising a single molecule."

The Munich researchers NEMS excites strings individually using dielectric interaction – the same phenomenon that makes hair stand on end in winter.

"This was easily done, even repeated ten thousand times on a chip," says Dr Eva Weig. "The only thing to do now is to make sure the strings can be individually addressed by a suitable circuit."

The new NEMS could also be used in other applications, such as acting as tiny pulse generators in mobile phone clocks.

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