Described in a recent paper,* their electronic nose is more adept than conventional methodologies at recognizing molecular features even for chemicals it has not been trained to detect and is also robust enough to deal with changes in sensor response that come with wear and tear.
The detector could be a potent tool for applications such as sniffing out nerve agents, environmental contaminants, and trace indicators of disease, in addition to monitoring industrial processes and aiding in space exploration.
In animals, odorant molecules in the air enter the nostrils and bind with sensory neurons in the nose that convert the chemical interactions into an electrical signal that the brain interprets as a smell. In humans, there are about 350 types of sensory neurons and many copies of each type; dogs and mice have several hundreds more types of sensory neurons than that. Odor recognition proceeds in a step-by-step fashion where the chemical identity is gradually resolved: initial coarse information (e.g. ice-cream is fruit-flavored vs. chocolate) is refined over time to allow finer discrimination (strawberry vs. raspberry). This biological approach inspired the researchers to develop a parallel “divide and conquer” method for use with the electronic nose.
The technology is based on interactions between chemical species and semiconducting sensing materials placed on top of MEMS microheater platforms developed at NIST. (See “NIST ‘Microhotplate’ May Help Search for Extraterrestrial Life,” NIST Tech Beat, Oct., 2001.) The electronic nose employed in the current work is comprised of eight types of sensors in the form of oxide films deposited on the surfaces of 16 microheaters, with two copies of each material. Precise control of the individual heating elements allows the scientists to treat each of them as a collection of “virtual” sensors at 350 temperature increments between 150 to 500 °C, increasing the number of sensors to about 5,600. The combination of the sensing films and the ability to vary the temperature gives the device the analytical equivalent of a snoot full of sensory neurons.
Much like people detect and remember many different smells and use that knowledge to generalize about smells they haven’t encountered before, the electronic nose also needs to be trained to recognize the chemical signatures of different smells before it can deal with unknowns. The great advantage of this system, according to NIST researchers Barani Raman and Steve Semancik, is that you don’t need to expose the array to every chemical it could come in contact with in order to recognize and/or classify them. Breaking the identification process down into simple, small, discrete steps using the most information rich data also avoids ‘noisy’ portions of the sensor response, thereby incorporating robustness against the effects of sensor drift or aging.
The researchers say that they are continuing to work on applications involving rapid identification of chemicals in unknown backgrounds or in a complex cocktail.
* B. Raman, J. L. Hertz, K. D. Benkstein and S. Semancik. Bioinspired methodology for artificial olfaction. Analytical Chemistry. Published online Oct. 15, 2008.
High-resolution version of image available at http://patapsco.nist.gov/ImageGallery/details.cfm?imageid=593
Mark Esser | Newswise Science News
Fish recognize their prey by electric colors
13.11.2018 | Rheinische Friedrich-Wilhelms-Universität Bonn
The dawn of a new era for genebanks - molecular characterisation of an entire genebank collection
13.11.2018 | Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
Physicists at ETH Zurich demonstrate how errors that occur during the manipulation of quantum system can be monitored and corrected on the fly
The field of quantum computation has seen tremendous progress in recent years. Bit by bit, quantum devices start to challenge conventional computers, at least...
09.11.2018 | Event News
06.11.2018 | Event News
23.10.2018 | Event News
13.11.2018 | Life Sciences
13.11.2018 | Life Sciences
13.11.2018 | Awards Funding