Conducting Polymer Nanomaterial-Based Sensor Platform for Bioelectronic Nose - Bioelectronic Nose: Integration of Biotechnology and Nanotechnology - page 252

Fig. 13.8 Calibration
curves of the FET B-nose
using various hOR-CPNT
sensing platforms (1hOR-
CPNT, 2hOR-CPNT, and
4hOR-CPNT). (Reprinted
with permission from
ref. [ 34 ]. Copyright 2009
Wiley-VHC Verlag GmbH
@ Co. KGaA)

number of carbon atoms (butyl butyrate, BB; propyl butyrate, PB; hexyl butyrate,
HB); whereas the target molecule (AB) exhibited a significant signal.
To confirm the loading effect of hOR on the CPNT surface, 1hOR-CPNT, 2hOR-
CPNT, and 4hOR-CPNT samples were prepared. Figure 13.8 shows the calibra-
tion curves of the FET B-nose. The 4hOR-CPNT, which offers the highest degree
of functionalization, showed the lowest MDL level (10 fM) as a result of the en-
hanced hOR-AB interaction. Moreover, the linear curves as normalized changes
in I ds , were observed after the addition of various AB concentrations. All of the
samples remained stable, as indicated by the linearity of the log-scale x -axis. The
sensitivity order of the samples over a wide concentration range was as follows:
1hOR-CPNT < 2hOR-CPNT < 4hOR-CPNT. In particular, the sensitivity of the
4hOR-CPNT was approximately twice that of 1hOR-CPNT or 2hOR-CPNT. From
these results, a high-performance B-nose can be constructed using hOR-CPNT
sensing platform, carefully controlled by the hOR loading amount.

13.5 Conclusion

Owing to attractive advantages, including easy functionality and facile fabrication
process, of the 1D CP nanomaterials, we demonstrated the construction of B-nose
based on 1D CP nanomaterials. The CPNT geometry, as a sensing platform for the
B-nose, can be constructed using an immobilization process on an IMA substrate.
His configuration exhibited stable electrical properties and mild reaction conditions
in the air or liquid. The B-noses, using the hOR-CPNT geometry, were utilized as
two kinds of sensing platforms: (i) as a chemiresistive B-nose using simple changes
in resistance, (ii) as a liquid-ion gated FET-type B-nose based on changes in current
flow. For discriminating odorant gases, the chemiresistive B-nose showed excel-
lent sensing performance. The FET-type B-nose also exhibited high-performance
odorant detection in the liquid state. Considering these results, the hOR-conjugated
CPNT sensing platform offers a new direction for mimicking human sensors. More-
over, this methodology can also be utilized for fabricating high-performance bio-
sensors with high sensitivity and selectivity.