Development of an odorant sensor with a cell-free synthesized olfactory receptor and a graphene field-effect transistor

Animals sense odorants using olfactory receptors. Many trials have been conducted to develop artificial odorant sensors using olfactory receptors. However, the development has been hindered by the difficulty in obtaining olfactory receptors. In this study, we expressed an olfactory receptor, cOR52, using a wheat germ cell-free synthesis system. The functionality of the expressed cOR52 was confirmed by ligand concentration-dependent interactions with the mini-G protein. The expressed cOR52 was immobilized on a graphene field-effect transistor. The cOR52-modified graphene field-effect transistor exhibited a ligand-specific response between 100 nM and 100 µM. This approach seems to be applicable for other olfactory receptors. Therefore, it will be possible to develop an odorant sensor equipped with various olfactory receptors by this method.