Biomedical Engineering Reference
In-Depth Information
Electrochemical sensors are largely studied and fabricated
by investigating two main approaches: (a) the modification of the
electrodes using the CNTs as high-performance nanomaterial to
enhance the electrical charge transfer and thus increase the gas
response in the sensor; (b) the employment of CNTs as innovative
platforms to immobilize covalently or noncovalently various
anchored functional materials such as enzymes, proteins, DNA
chains, receptors, antibodies, macromolecules, polymers, metals,
and other foreign materials in order to improve the chemical
interaction between targeted molecules to be detected and the
micro/nanoelectrodes in the electrochemical sensors due to the
comparable sizes of the specific molecules to be sensed and the CNT-
based nanoplatforms.
. [284-286] demonstrated the possibility to use CNTs
to modify the electrodes in the electrochemical sensors immersed in
aqueous and nonaqueous solutions. In particular, an electrochemical
quartz crystal microbalance (QCM) was modified with SWCNTs for
studying the voltammetric properties of various electrolytic solutions
showing that the QCM electrode mass increased with increasing
negative potentials and was associated to double-layer charging in
the CNT electrode. Liu
Barisci
et al
. [287] demonstrated the usage of carbon
nanotube powder in electrochemical microelectrodes for nitrite
detection in acidic solutions with a low detection limit as 10
et al
−7
M at
signal-to-noise ratio of 4.
. [288] demonstrated a carbon nanotube/teflon
composite as electrochemical sensors and biosensors for marked
electrocatalytic activity toward hydrogen peroxidase providing low-
potential amperometric detection of glucose and ethanol. Pumera
et al
Wang
et al
. [289] demonstrated carbon nanotube/epoxy composite for
electrochemical sensing as well. Additionally, Weeks
. [290]
demonstrated an enzymatic amperometric biosensor using vertically
aligned carbon nanofibers for biosensing applications.
et al
. [250] demonstrated functionalized SWCNTs
modified microsensors for the selective response of epinephrine in
presence of ascorbic acid. Modified stainless steel microelectrodes
(microwire diameter: 300 mm) were assembled using functionalized
SWCNTs deposited by the electrophoretical deposition process
(EPD) method. The functionalized SWCNTs, which covered the
microelectrode surfaces, showed an improved sensitivity and
selectivity toward the electrochemical detection of epinephrine.
Valentini
et al
