Background

The sense of smell provides very useful information to animals by helping to analyse, distinguish or identify numerous odorants. The approach towards development of artificial olfactory systems generally resembles their biological counterparts where the olfactory receptors react to chemical stimuli of the odorant and generate signals for the information to be perceived by the brain. The broad and diverse range of smells animals can process are a result of at the very least, thousands of years of evolution. To develop an artificial intelligence system, capable of replicating mammalian olfaction abilities, sensors capable of detecting chemical analytes need to be developed. Research in chemistry has shown promise and potential to develop advanced vapour sensitive materials, taking these devices closer to an artificial olfactory sensor platform that mimics its biological equivalent.

Technology Overview

This sensor platform involves the use of commercially available, silicon-based floating gate devices that have been functionalized through selective, electrochemical polymer deposition to produce of “programmable” olfactory sensor arrays. This work has been successful in developing sensors and circuitry for sensor array systems that can contain many different polymers deposited selectively via electrochemistry. This type of design enables a sensing array platform that contains many different polymers making it sensitive to many analytes simultaneously. Feasibility and proof concept of these sensors has been seen for chips functionalized with several different polymers exposed to many analyte compounds (including acetone, ethanol, methanol, ammonium hydroxide, toluene, isopropanol alcohol, acetic acid, petrol and water).

The silicon “chips” are designed as a platform such that any electrochemically deposited polymer may be used making the sensor array “effectively programmable” for any groups of olfactory molecules. The current design includes only 4x4 and 8x8 arrays. However, this can be expanded to have 1000s or even 1,000,000s of array elements; size and the level of integration are the only limits to the number of sensors available on a given device.

Publication: Dubey, M. Freund and D. A. Buchanan, “A dual gate MOS-based olfactory system functionalized using conducting polymers,” 2019 IEEE SENSORS, Montreal, QC, Canada, 2019, pp. 1-4.

Benefits

This sensor platform can be fabricated using the simplest of CMOS technologies, making it relatively inexpensive for mass production. The use of CMOS technology brings it’s inherent advantages like smaller size and lower power consumption. The sensor array on the chip could contain a multitude of different polymers deposited via a bias applied to the floating gate of that individual device, making the device completely “programmable. This makes this sensor array system extremely flexible and therefore it could be applied to many industries where the sensing of volatile analytes is required.

Applications

There are numerous uses for this platform technology. The system can be programed to detect odours or “analytes” for detection of chemical leaks, quality control in food processing, medical diagnosis and testing, fabrication and manufacture of commercial and industrial goods, pharmaceutical production, testing or evaluating any odorant or analyte in any medium (e.g., fuel, oil, wine, whiskey solvents), and other applications. This platform would be highly desirable in industries and applications such as the chemical and petrochemical sectors, food, fragrance, medical, automotive, military, environmental, health and safety, and indoor air quality.

Artificial Olfactory Sensor Platform

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