Peptide-Functionalized Graphene Sensors for Selective Odorant Detection

Gas sensing based on graphene field-effect transistors (GFETs) has gained broad interest due to their high sensitivity. Further progress in gas sensing with GFETs requires the detection of various odor molecules for applications in environmental monitoring, healthcare, food, and cosmetic industries. To establish an artificial sense of smell with electronic devices by mimicking olfactory receptors, it is desirable to use synthetic molecules with similar functionality. In this work, we designed three new peptides based on a motif sequence in olfactory receptors. These peptides were designed to have two domains: a bio-probe specific to the target molecules and a molecular scaffold [1,2]. The scaffold peptides have the ability to self-assemble into a molecular thin film on GFETs [3].<br/>To demonstrate the biosensing capabilities, we employed limonene, methyl salicylate, and menthol as representative odor molecules of plant flavors. We investigated the conductivity change of GFETs upon binding to odor molecules at various concentrations. The dynamic response of the sensors revealed distinct signatures for each of the three different peptides against individual target molecules. The kinetic response of each peptide exhibited characteristic time constants in the adsorption and desorption processes, which were further supported by principal component analysis. These results demonstrate the selectivity of the designed peptides in detecting odor molecules.<br/>The development of graphene odor sensors using these designed peptides paves the way for future peptide-array sensors with multiple sequences, enabling the realization of an odor-sensing system with higher selectivity. Combining the bio-probe and electrical signal amplification functions, the peptide layer on graphene represents a novel and effective strategy for achieving selective odorant detection under normal atmospheric conditions. This research contributes to the advancement of biomimetic devices and holds potential for various applications in odor detection and identification.<br/>This work was supported by the Cabinet Office (CAO), Cross-ministerial Strategic Innovation Promotion Program (SIP), “Intelligent Processing Infrastructure of Cyber and Physical Systems” (funding agency: NEDO).<br/><br/><b>References</b><br/>[1] T. Rungreungthanapol, C. Homma, K.-I. Akagi, M. Tanaka, J. Kikuchi, H. Tomizawa, Y. Sugizaki, A. Isobayashi, Y. Hayamizu, M. Okochi, Volatile Organic Compound Detection by Graphene Field-Effect Transistors Functionalized with Fly Olfactory Receptor Mimetic Peptides. <i>Anal. Chem.</i> <b>95</b>, 4556–4563 (2023).<br/>[2] C. Homma, M. Tsukiiwa, H. Noguchi, M. Tanaka, M. Okochi, H. Tomizawa, Y. Sugizaki, A. Isobayashi, Y. Hayamizu, Designable peptides on graphene field-effect transistors for selective detection of odor molecules. <i>Biosens. Bioelectron.</i> <b>224</b>, 115047 (2022).<br/>[3] P. Li, K. Sakuma, S. Tsuchiya, L. Sun, Y. Hayamizu, Fibroin-like Peptides Self-Assembling on Two-Dimensional Materials as a Molecular Scaffold for Potential Biosensing. <i>ACS Appl. Mater. Interfaces</i>. <b>11</b>, 20670–20677 (2019).