Biomedical Engineering Reference
In-Depth Information
nanotube arrays possess
large surface area and good uniformity and are ready for enzyme
immobilization [165-167], which can be used as biosensors.
Furthermore, different length of TiO
2
different electrolytes. The produced TiO
2
nanotube arrays fabricated
by anodic oxidation in different electrolytes were studied for their
sensitivities to hydrogen peroxide after co-immobilized horseradish
peroxidase (HRP) and thionine chloride. The nanotube arrays
fabricated in potassium fluoride solution has the best sensitivity to
H
2
O
2
M [156].
With the use of the template of an AAO, TiO
with a detection range from 10
-5
to 3×10
-3
nanowires can
be also obtained by cathodic electrodeposition [168,169] where
the metallic ions are attracted to the AAO cathode electrode and
reduced to metallic form. For example, in a typical process, the
electrodeposition is carried out in 0.2 M TiCl
3
2
solution with pH = 2
with a pulsed electrodeposition approach, and titanium and/or
its compound are deposited into the pores of the AAO. By heating
the above deposited template at 500
°
C for 4 h and removing the
template, pure anatase TiO
2
nanowires can be obtained. In addition,
highly ordered TiO
2
single crystalline (pure anatase) nanowire
arrays can be fabricated within the pores of anodic aluminum oxide
(AAO) template by a cathodically induced sol-gel method [170].
During this electrochemically induced sol-gel process, both the
formation of sol particles and the gelation process take place in the
AAO pores. Therefore, TiO
nanowires with very small diameters
(less than 20 nm or even smaller) can be obtained by this technique.
In addition, the length of the nanowires can be well controlled by
varying the deposition time and potential of the working electrode.
2
1.9.4 Electrochemical Fabricaion of Sot Maters in
Nanoscale Using Templates
Conducting polymer nanowires are promising one-dimensional
nanostructured materials for application in nanoelectronic devices
and sensors [171,172] due to their light weights, large surface
areas, chemical specificities, easy processing with low costs, and
adjustable transport properties. Nanofiber, nanospheres, and other
nanoscales of soft matters such as conducting polymers have been
fabricated in traditional chemistry way and/or via self-assembly
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