Graphene Field-Effect Transistor-Based Chemical Sensor With Functionalized Olfactory Receptors Immobilized in Solid Phase for Household Odor Detection

In this letter, we present a novel graphene field-effect transistor (gFET)-based chemical sensor that utilizes mammalian olfactory receptors (ORs) as selective gas-capturing materials for indoor odor detection. We have completed an electrochemical gating circuit that can directly measure gaseous targets without using a liquid medium by functionalizing hydroxyl ethyl piperazine ethane sulfonic acid (HEPES) with ORs as the gas reaction layer and utilizing a graphene passivation layer as the FET gate. The gFET using HEPES-functionalized ORs was successfully fabricated through a standard CMOS-compatible manufacturing process. Our odor gas sensor can detect diluted trimethylamine (TMA) gas in air at concentrations of 100 ppb and can distinguish it from other gases, such as formaldehyde and toluene. We expect that it can be applied to household appliances to help indoor residents identify the cause of odors, such as fish spoilage and foot odor, by better understanding the context of odors. In fact, we anticipate that this odor gas sensor can be applied to refrigerators, indoor air purifiers, and other products.