Conducting Polymer Nanomaterial-Based Sensor Platform for Bioelectronic Nose - Bioelectronic Nose: Integration of Biotechnology and Nanotechnology - page 243

Fig. 13.2 a Partial ternary phase diagram for the hexane/AOT/ Fe cations system determinated
at 15 °C. Reprinted with permission from ref. 67. Copyright 2005 American Chemical Society.
b XPS spectra of the CPNTs. c XPS O 1s spectrum of the CPNTs. d Typical FE-SEM images of
CPNTs on the microelectrodes. (Reprinted with permission from ref. 32. Copyright 2012 Elsevier)

electron microscopy (FE-SEM) was used to characteriz morphology of the CPNTs.
Figure 13.2d shows the SEM image of the CPTNs on the microelectrodes, which
had no impurities and a smooth surface [ 32 ].

13.3.3 Preparation of hORs

Two kinds of olfactory receptors as a fusion protein with a glutathione- S -transferase
(GST) tag at its N terminus were prepared: hOR2AG1 and hOR3A1 were expressed
in Escherichia coli ( E. coil ). The hOR2AG1 was used for the B-nose in liquid
state; the other (hOR3A1) was introduced as a transducer for the B-nose in air. The
GST-tag allows the information of olfactory receptor such as successful expression
and Western blot analysis. The ORs can be separated from a membrane fraction
of E. coli cells using Triton X-100, because the impurity proteins are soluble in
Triton X-100. These ORs, which belong to a family of G protein-coupled receptors
(GPCRs), are used for drug discovery and play a key role in odor discrimination.