One way to develop devices for odor detection is to mimic multiple attributes of biological olfactory systems, taking advantage of the millions of years of evolutionary optimization. In addition to the cross-reactive sensor arrays that replicate biological odorant receptors, such devices can respond rapidly without prior sample preparation, can implement real-time dynamic modulation of sampling and detection parameters, and can utilize sophisticated analyte detection algorithms. These devices exhibit high sensitivity, discrimination, and detection capability for target analytes, in some cases at sub-parts-per-billion levels.

Both DNA-based sensors and other fluorescent dye-coupled sensor materials may be used to generate spatio-temporal optical response patterns to volatile compounds that are identified through use of algorithms consisting of template matching, neural networks, delay line neural networks, and statistical analysis. Interferents are handled in a variety of ways by judicious choice of sensors unresponsive to ambient vapors, or by subtracting responses identified through use of other sensors relatively specific for defined interferents.

Research supported by the Homeland Security Advanced Research Projects Agency (HSARPA) has demonstrated that optoelectronic noses using these principles can detect a variety of toxic industrial compounds and chemical warfare agents in the presence of a number of interferent compounds. Ongoing tests are examining the ability to detect these compounds at low concentrations that may endanger life or health with an eye to providing such a detection system to the first responder community.

This article was written by John S. Kauer, Ph.D., Chief Scientific Officer and Chairman of the Board; and Barbara R. Talamo, Ph.D., Vice President for Business Development, at CogniScent, Inc. For more information, phone 508-839-7973, or visit http://info.hotims.com/10960-122.