Development of Cell-Based Olfactory Biosensors

The olfactory system is responsible for the discrimination and identification of myriad odorant molecules at very low concentrations. On the basis of the gene super family encoding olfactory receptors, it has led to the rapid development of cell based olfactory biosensors. Attempts are currently made not only to imitate the mechanism of the biological nose but also to utilize some of its sensor molecules as functional unities in olfactory biosensors. Recently, the development of olfactory biosensors has achieved rapid advances by using protein molecules and cells, even biological organs as functional elements, that is, odorant binding proteins (OBPs) and olfactory receptors (ORs) at the molecular level, cell based gene engineered cells or olfactory receptor neurons (ORNs), and mammalian olfactory organs. With using the living cells expressing olfactory signal proteins as sensing elements, the cell based biosensors have a naturally evolved selectivity to odorant molecules. Furthermore, the biosensors also have the capacity to respond to odorant in a physiologically relevant manner. In this paper, we briefly introduce the molecular basis of olfaction and summarize the cell based olfactory biosensors.