Conducting polymer nanomaterial-based sensor platform for bioelectronic nose

Significant efforts in the fabrication of conducting polymer (CP) nanomaterials have enabled various electronic devices such as solar cells, memory devices, batteries, and field-effect transistors (FETs). Specifically, well-designed one-dimensional (1D) CP nanostructures have gained attention in various biosensing applications due to their 1D geometry, which can facilitate efficient charge-transfer behavior and signal amplification. Recently, researchers have demonstrated various nanomaterial-based odorant sensing geometries with sensitivity and selectivity. Although these conventional odorant sensing platforms provide significant and sensitive performance, limitations such as low sensitivity, slow response time, and an unstable platform in the liquid state remain as challenges. Herein, we developed a novel fabrication process for functionalized 1D CP nanomaterials, conjugated with human olfactory receptors (hORs), a so-called bioelectronic nose (B-nose), through an immobilization process. The sensing platforms using 1D CP nanomaterials were integrated into a liquid-ion gated FET system, resulting in the development of a high-performance FET-type B-nose. Real-time responses from the B-nose were monitored with ultrasensitive and selective responses at unprecedentedly low concentrations of the target odorant. The B-nose also showed single-atom-resolution for target odorants among similar non-target odorants. Moreover, the 1D CP nanomaterial-based B-nose can discriminate target odorants in the gaseous state, with sensing capability comparable to that of a human expert's nose. The B-nose opens the possibility for efficient methodology for smell mechanism studies. Based on these results, the study of the B-nose using 1D CP nanomaterials opens up challenging research opportunities including these related to the food industry, disease diagnosis, and public safety.