Tuesday, November 20, 2007
Nanowire-based Electronic Nose
Filed under: Nanomedicine
An international group of scientists is working on developing an artificial olfactory system, based on some of the most technically challenging nanotechnologies, that one day might be employed as a diagnostic sensor, or even as an imaging modality.
Michael Berger from Nanowerk reports:
Kolmakov, an assistant professor in the physics department at Southern Illinois University at Carbondale points out that this work is an example of successful truly international collaboration between his group, Dr. Victor Sysoev (electronic noses specialist, Saratov State University, Russia) and group of Dr. Joachim Goschnick (developers of the commercial KAMINA e-nose system Forschungszentrum Karlsruhe, Germany).
"Basically, we took a very robust and successful KAMINA (KArlsruhe Micro NAse; pdf download (.pdf) German/English datasheet, 128 KB) electronic nose platform and instead of using the traditional thin-film sensing element we implemented completely new morphology of the sensing layer, which in our case, is composed out of the layer of tin oxide nanowires" says Kolmakov.
He explains that their device shows a certain degree of analogy with neurons: The randomly distributed nanowires contact each other and form multiple percolation paths for signal transmission. The resistance of these percolating nanowires is a very sensitive function of the gas environment. Due to a stochastic difference of the percolating pattern between every two electrodes (the space between each couple of electrodes serves as a separate sensor), the sensor array of multi-electrodes produces a different response pattern to differing analytes. Similar to our brain, the processor attached to the e-nose conditions and analyzes the electrical signals coming from the sensor array and, using pattern recognition techniques, produces the image of the 'odor'.
This is a far more advanced system than what Kolmakov and his collaborators demonstrated last year. In this new device, the scientists decided to benefit from the stochastic nature of the percolating nanowire network.
More from Nanowerk...
KAMINA electronic nose system (.pdf)...
ACS abstract: A Gradient Microarray Electronic Nose Based on Percolating SnO2 Nanowire Sensing Elements...
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