Biology and applications of olfactory sensing system: A review

Various metal oxide and conducting polymer-based sensors have been used in electronic nose systems for the detection of volatile organic compounds (VOCs). Some of the major constrains of these sensor materials are their sensitivity and selectivity. Recently, much research has been towards the development of biosensors that mimic biological olfactory mechanism. The sensing materials based on biological olfactory system can be well adapted to detect low concentrations of VOCs as it exhibits high selectivity/specificity, fast response time, high sensitivity, simplicity in fabrication, and are not toxic resulting from their biocompatibility and rapid biodegradability. A better understanding of human olfactory system can aid in the development of an artificial olfactory sensing system. The application domain of such sensors/systems could be potentially expanded for rapid and accurate detection of VOCs in environment and other biological media. Therefore, this paper provides a brief overview of the biology, associated mechanisms, and the functional principles of the olfactory sensing system in humans. Moreover, it summarizes the recent research on the development of an olfactory sensor utilizing olfactory receptors, odorant binding proteins and olfactory epithelium for the detection of different VOCs, and research needs in this area. (C) 2012 Elsevier B.V. All rights reserved.