Biomedical Engineering Reference
In-Depth Information
Chapter 12
Carbon Nanotube-Based Sensor Platform
for Bioelectronic Nose
Juhun Park, Hye Jun Jin, Hyungwoo Lee, Shashank Shekhar, Daesan Kim
and Seunghun Hong
Abstract
Since carbon nanotubes (CNTs) have an extremely large surface-to-vol-
ume ratio, the electrical properties of CNTs can be easily changed by the adsorp-
tion of small molecules. Due to this attribute, CNT-based sensors can detect small
molecules with a high sensitivity. Recently, bioelectronic noses based on CNTs
have been developed by immobilizing olfactory receptors or nanovesicles on the
surface of CNTs. By taking advantages of CNT structures, these bioelectronic nose
devices allowed one to detect target odorants with a high sensitivity. Furthermore,
they exhibited highly selective responses to target odorants with a single-carbon-
atomic resolution just like human olfactory systems. These bioelectronic nose
devices based on CNTs can be utilized for various practical applications such as
food screening, medical diagnostics, and the fabrication of artificial noses.
12.1
Carbon Nanotube-Based Device Fabrication
12.1.1
Carbon Nanotubes
A tube made of a single or multiple graphene layers rolled up into a hollow cylinder
is called a carbon nanotube (CNT) [
1
]. A single-walled CNT (SWCNT) consists of
a single graphene sheet with the diameter of about 1 ~ 2 nm, while a multi-walled
CNT (MWCNT) consists of several graphene sheets. Among those nanotubes, spe-
cial attentions have been focused on SWCNTs, since they can have semiconducting
properties which are optimal for electronic device applications. Despite the fact that
all SWCNTs are based on a hexagonal honeycomb lattice, different orientations
in the basic structure with respect to a nanotube axis lead to electrically different
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