Gas Phase Odorant Detection by Insect Olfactory Receptor

The OR (olfactory receptor) with its high selectivity and sensitivity attracts many researchers to apply it to numerous kinds of odor biosensors. Till now, the liquid phase odorant detection has been well studied. However, most of the odorant molecules that scientists are interested in are hydrophobic and exist in atmosphere. Meanwhile, some odorant samples to be detected are precious and hard to collect. Here, we developed a gas phase odorant detection system using cell expressing insect OR. We then tested it with target ligand as well as reference gas and obtained the typical OR response. After this, we checked the influence of stimulation duration and liquid thickness to it. Moreover, the detection limit and selectivity were confirmed by a series of experiments. In addition, the sample concentration dependency was exhibited and a hypothesis towards inhibition phenomenon was proposed. Lastly, a human sensory test was operated to compare the performance of our system with human olfaction. In our system, only sub-milliliter target odorant was enough to trigger the OR response. Altogether, these results suggest this odor biosensor can be applied to gas phase odorant detection in multiple aspects owning to its detection capability and rapid response.