Volatile Organic Compound Detection by Graphene Field-Effect Transistors Functionalized with Fly Olfactory Receptor Mimetic Peptides

Abstract

An olfactory receptor mimetic peptide-modified graphene field-effect transistor (gFET) is a promising solution to overcome the principal challenge of low specificity graphene-based sensors for volatile organic compound (VOC) sensing. Herein, peptides mimicking a fruit fly olfactory receptor, OR19a, were designed by a high-throughput analysis method that combines a peptide array and gas chromatography for the sensitive and selective gFET detection of the signature citrus VOC, limonene. The peptide probe was bifunctionalized via linkage of a graphenebinding peptide to facilitate one-step self-assembly on the sensor surface. The limonene-specific peptide probe successfully achieved highly sensitive and selective detection of limonene by gFET, with a detection range of 8−1000 pM, while achieving facile sensor functionalization. Taken together, our target-specific peptide selection and functionalization strategy of a gFET sensor demonstrates advancement of a precise VOC detection system.

Enantioselective Detection of Gaseous Odorants with Peptide–Graphene Sensors Operating in Humid Environments

“…Similar to prior studies, ,− we employed peptides with self-assembly capability into molecular films on surfaces, accomplished through a series of surface processes involving adsorption, diffusion, and intermolecular interactions. Noncovalent interactions between the peptides and the surface facilitate their surface diffusion, eventually leading to their ordering along specific directions (Figure a).…”

“…P1 peptide containing FLLF (F: Phenylalanine and L: Leucine) connected to the N-terminus of GR3R was rationally designed. This sequence mimics a part of the sequence of the olfactory receptor Or19a. − The sequence of the LBP3 peptide was experimentally found as a strong binder of d -limonene . Short peptide libraries derived from OR19a were synthesized on a peptide array, and the amount of bound d -limonene on each peptide was analyzed, allowing a simultaneous exploration of the whole receptor protein .…”

“…This sequence mimics a part of the sequence of the olfactory receptor Or19a. − The sequence of the LBP3 peptide was experimentally found as a strong binder of d -limonene . Short peptide libraries derived from OR19a were synthesized on a peptide array, and the amount of bound d -limonene on each peptide was analyzed, allowing a simultaneous exploration of the whole receptor protein . In the demonstration, we employed d -limonene, l -limonene, (-)-menthol, methyl salicylate, and ethyl propionate as target odor molecules to evaluate the selectivity of the proposed GFET gas sensor (Figure c).…”

“…38 Short peptide libraries derived from OR19a were synthesized on a peptide array, and the amount of bound Dlimonene on each peptide was analyzed, allowing a simultaneous exploration of the whole receptor protein. 38 In the demonstration, we employed D-limonene, L-limonene, (-)-menthol, methyl salicylate, and ethyl propionate as target odor molecules to evaluate the selectivity of the proposed GFET gas sensor (Figure 1c). First, we examined whether these peptides could form a thin film on the graphite surface through self-assembly.…”

Detection of medically relevant volatile organic compounds with graphene field-effect transistors and separated by low-frequency spectral and time signatures

“…30,31 Previous research studies on the topic of VOC detection with GFETs have used functionalized graphene to target individual compounds. [32][33][34][35][36][37] Although this approach yields higher specificity towards the selected VOC, it cannot be applied to a different compound with similar performance metrics. Due to the heterogeneous composition of most biological fluids and exhaled condensate in terms of VOC content (that is, many VOCs reported for the same medical condition as previously mentioned), we believe that a universal graphene template must be deployed without specifically targeting single compounds by chemical functionalization; instead it must provide identical physical interaction with a larger group of compounds, from which characteristic physical signatures can be identified by different measurement modalities and relative to a common baseline, such as (inert) nitrogen gas.…”