Sensors Mag

CogniScent could Help Spearhead E-Nose Sensing

August 1, 2006 By: Peter Adrian


This content is excerpted from Sensor Technology Alert and Newsletter, a sensor intelligence service published by the Technical Insights unit of Frost & Sullivan.

Sensor Technology Alert

Electronic noses--which are chemical sensing devices that can use an array of relatively nonspecific sensors along with pattern recognition techniques to identify and analyze the response patters from a substance of interest--have thus far largely been confined to research-oriented, niche applications in such sectors as food and beverage processing, packaging, petrochemical/chemical, fragrances. However, there has been keen interest in e-nose sensors for identifying chemical warfare agents and toxic industrial chemicals, and interest in utilizing e-noses for such applications as medical diagnostics (for example, breath or respiratory analysis), and detection of volatile organic compounds (VOCs). Opportunities for e-noses would be significantly enhanced by the wider availability of electronic nose sensors capable of reliably detecting a wider range of odors/substances in difficult environments at a low cost.

CogniScent Inc., founded in 2002, is finding expanding, real-world opportunities (in such areas as mold detection and detection of chemical warfare agents and toxic industrial chemicals) for its optical e-nose technology, which uses an array of sensors that can respond to a wide array of analytes, purportedly allowing for efficient detection of a broad range of targeted substances.

CogniScent's e-nose technology, which detects volatile chemical compounds using principles observed in studies on the olfactory system, evolved from neuroscience research conducted at Tufts University School of Medicine by John Kauer, and Joel White, CogniScent's founders. The company's sensing technology enables light-weight, handheld, highly sensitive, electrooptical sensing devices that model the way biological noses work to detect, identify, and discriminate different airborne compounds in real time.

Hugh Greville, CogniScent's President and CEO, told Sensor Technology that, in contrast to the typical e-nose, which uses the spatial patterns of response across their sensors for each odor compound of interest, CogniScent's technology uses an array of rapidly responding sensors that change both their spatial patterns and their temporal patterns as a way of widening the range of analytes detected and eliminate background interference. Dies, polymer matrices, and a proprietary material based on DNA are used in CogniScent's e-nose sensing technology.

CogniScent's sensing technology does not require sample preconcentrations and uses off-the-shelf optoelectronic components. The company's e-nose technology is purportedly able to provide engineered odor detection solutions more quickly, at higher volume, and at greater sensitivity and lower cost, compared to currently available technologies.

In CogniScent's ScenTraK optoelectronic technology, each sensor channel in the array has an LED and photodiode. Light is passed through across a fluorescing sensor (a dye-tagged tagged material that shows a change in fluorescence). The fluorescent light is detected by photodetectors and the change in fluorescence is measured. The signal is reported to pattern recognition algorithms and the target substance identified by comparison with patterns stored in memory. The ScenTraK platform models olfactory sensing by using 23 biologically-inspired attributes; and can detect, identify, an discriminate numerous different airborne contaminants in real-time (about 2 seconds).

The company's ScenTraK technology is covered by two patents: Intelligent electrooptical sensor array and method for analyte detection (US Patent 6,649,416, issued November 2003); and Intelligent electrooptical nucleic acid-based sensor array and method for detecting volatile compounds in ambient air (US Patent 7,062,385, issued June 2006).

The invention described in US Patent 6,649, 416 relates to a chemical sensor, sensing system and sensing and identification method. These provide for a multisensor, cross-reactive, sensor array that has a rapid response time, rapid sampling time, dynamic modulation of sampling and detection parameters, intelligent feedback control of analyte sampling conditions, smart mode sampling, smart detection through application of sophisticated analyte detection algorithms, and high sensitivity, discrimination, and detection capability for a variety of target analytes at sub parts per million (ppm) to parts per billion (ppb) level concentrations.

In US Patent 7,062,385 it is noted that: "We have, surprisingly, discovered that nucleic acids with attached fluorophores and dried onto a substrate react with volatile chemical compounds in ambient air and can be used as sensors to detect compounds in the air that reacts thereto. This is distinctly different from other nucleic acid-based sensing materials that work only when both the analytes and the nucleic acid materials are dissolved in aqueous solution."

"Accordingly, the present invention provides a nucleic acid-based chemical sensor, sensing system and sensing and identification method which provide for a nucleic acid-based multisensor, cross-reactive, sensor array having a rapid response time, a rapid sampling time, dynamic modulation of sampling and detection parameters, intelligent feedback control of analyte sampling conditions, smart mode sampling, smart detection through application of sophisticated analyte detection algorithms, high throughput screening of sensors, and high sensitivity, discrimination, and detection capability for a variety of target analytes."

CogniScent purportedly has an unlimited supply of potential sensors through its proprietary use of DNA as a sensing material. The company's technology can allow for high-throughput screening of millions of individual potential sensors to find optimal sets for specific odor detection applications. By using standard high-throughput DNA screening and processing methods, CogniScent could significantly reduce the economics of sensor identification and custom-build low-cost sensors for particular applications.

While their sensing technology has potential in diverse areas, including security, medical, and industrial markets, CogniScent, currently, is primarily focusing on two key target markets/applications: mold detection; and a handheld unit for first responder hazardous materials (HAZMAT)/chemical warfare agent (CWA) detection. The target markets dovetail with CogniScent's development activities.

CogniScent presently has two projects with the US Department of Homeland Security. One of them, an SBIR Phase II project, deals with detection of low-vapor pressure chemicals. The other, a HSARPA Phase II LACIS program, involves the development of a portable device to detect toxic industrial chemicals (TICs) and CWAs. Such substances could include, for example, chlorine, hydrogen cyanide, sulfur dioxide, phosgene, ammonia, and sarin. In 2006, the DHS will test the technologies and certain technologies will be selected to proceed to Phase III of the program in 2007. Greville explained that the selection criteria would include performance, cost, portability, and the ability to reduce susceptibility to interferences and reduce false positives.

The handheld unit developed via the HSARPA LACIS program will be aimed at, for example, fire departments, military HAZMAT teams, and industrial HAZMAT teams. Greville noted that detectors for CWAs and TICs tend to have a limited range, and that ion mobility spectrometers (a major technology now used in trace [part-per-billion] level chemical agent detection), are expensive and can be subject to interference.

CogniScent and Hamilton Thorne Biosciences Inc. have been collaborating to develop an e-nose for the detection of fungal organisms (mold). CogniScent has granted Hamilton Thorne Biosciences an exclusive license to market CogniScent's technology for mold detection.

In 2006, the Scentaur, a portable device aimed at owners and inspectors of commercial and residential buildings, will become available from Hamilton Thorne Biosciences. It will be priced at around $3,500 to $4,000. The Scentaur will allow for point-of-source, on-site screening of fungal organisms, thereby mitigating against litigation, clean-up costs, and structural damage caused by toxigenic molds. In contrast to "supposition" technologies (such as radar), which aim to detect mold behind wallboard (moist sheetrock) by essentially detecting moisture, CogniScent's technology will detect odors produced from VOC emissions from mold. Such VOCs will primarily contain a mixture of long chain alcohols and ketones. While there are a plethora of fungi in the environment, it would be beneficial to be able to identify microbial contamination based on odors in order to quickly and accurately identify the source. Current methods of diagnosing fungal types, such as gas chromoatography/mass spectrometry, are expensive and time consuming.

CogniScent is seeking partners to develop platforms for other applications (for example, explosives detection, other industrial applications).


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