With the increasing threat of environment toxicants including biological and chemical warfare agents,fabricating innovative biomimetic system to detect these harmful and dangerous agents is critically important.Various approaches to develop artificial odorants detectors have been reported.Most traditional sensors based on metal-oxide semiconductors,quartz crystal microbalances,surface Plasmon resonators,or surface acoustic wave devices are intended to imitate the signal processing in natural noses,although the elementary steps of signal transduction,signal processing,and identification of chemical patterns evidently differ drastically from those realized in the biological nose.Thus now,it has been difficult to develop a chemical sensor or biosensor that possesses all natural noses sensing properties.Insect has a highly sensitive and selective discrimination capacity for odorants in the ambience.Its olfactory signaling transduction is based on ligand-gated ion channels,independently of G-protein signaling,whose olfactory system is much simpler than mammalians.Thus,insects cells represent attractive tools for realizing highly selective and sensitive biosensors.In the current study,we screened for olfactory receptors from insect species that could report the presence of the volatile odorant of illicit substance,and co-expressed these olfactory receptors genes with a companion receptor in Xenopus oocytes or HEK cells.