Nanodisc-Based Bioelectronic Nose Using Olfactory Receptor Produced in Escherichia coli for the Assessment of the Death-Associated Odor Cadaverine

Abstract

Cadaverine (CV), a death-associated odor, is an important target molecule for various sensor applications, including the evaluation of food spoilage. In this study, we developed an oriented nanodisc (ND)-functionalized bioelectronic nose (ONBN), based on carbon nanotube transistors and nanodiscs embedded with an olfactory receptor produced in Escherichia coli (E. coli) for detection of CV. To fabricate ONBN devices, a trace-amine-associated receptor 13c (TAAR13c) binding to CV was produced in E. coli, purified, reconstituted into NDs, and assembled, in the desired orientation, onto a carbon- nanotube-based field-effect transistor with floating electrodes. The ONBN showed high performance in terms of sensitivity and selectivity. Moreover, the ONBN was used to measure CV in diverse real-food samples for the determination of food freshness. These results indicate ONBN devices can be utilized to evaluate the quality of food samples quantitatively, which should enable versatile practical applications such as food safety and preservative development. Moreover, the ONBN could provide a useful tool for detection of corpses, which could be practically used in disaster responses.

Human-like smelling of a rose scent using an olfactory receptor nanodisc-based bioelectronic nose

“…The cloning procedure of hOR1A2 was similar to that in a previous report 19 . The hOR1A2 genes were amplified by polymerase chain reaction (PCR) using human genomic DNA.…”

“…Luciferase assays were performed in a similar way to a previous study 19 . Human embryonic kidney (HEK)−293 cells were grown in Dulbecco’s Modified Eagles Medium (DMEM) (HyClone, USA) supplemented with 10% Fetal Bovine Serum (FBS) (Gibco, USA), 1% streptomycin (Gibco, USA), and 1% penicillin at 37 °C under 5% CO 2 .…”

“…The expression and purification of hOR1A2 were performed in a similar way to a previous report 19 . BL21 (DE3) E. coli cells were transformed by a pET-DEST42/hOR1A2 vector.…”

The Emergence of Insect Odorant Receptor-Based Biosensors

“…hOR, human odorant receptor; DmelOR, Drosophila melanogaster odorant receptor; MDL, minimum detection limit. Data cited from: Jin et al [35]; Goldsmith et al [36]; Yang et al [46]; Lee et al [47]; Murugathas et al [48]; Khadka et al [49]; Sung et al [50]; Lim et al [51]; Oh et al [52]; Park et al [53]; and Ahn et al [54].…”

“…The transduction of odorant binding into electronic readout (i.e., conductance changes) has shown reproducible responses over long periods of days and remarkably, even weeks [36]. In another example, researchers fabricated nanodiscs containing the TAAR13c G-protein coupled receptor (GPCR) from zebrafish, which functions as a highly selective OR for cadaverine [46]. The nanodiscs were immobilized on floating electrodes of a CNT-FET and the resulting bioelectronic nose exhibited a dose-dependent response in the form of increased conductance following repeated exposure to cadaverine concentrations as low as 10 pM.…”