Biology Reference
In-Depth Information
immobilization [129]. The Ppy layer was overoxidized potentiosta-
tically at the potential of
+
1.8 V vs. Ag/AgCl. The prepared DNA-
Ppyox-modified carbon fiber electrode showed excellent sensitivity
and selectivity toward neurotransmitters. In order to increase the
permeability of the Ppy film, an electrochemical overoxidation was
also performed by cycling the potential between 0.0 and 1.3 V vs.
Ag/AgCl until the reversible peak, indicating the Ppy conductivity
disappeared [130, 131].
10.5 Conclusions
Today, there is an increasing interest in the construction and
utilization of DNA biosensors. Successful DNA immobilization plays
a key role in the final e
ciency of biosensors. Using polymers
seems to be an elegant way for immobilization of biomolecules.
Moreover, conducting as well as nonconducting polymers not
only represent a matrix suitable for DNA immobilization but also
increase the sensitivity and selectivity of the final biosensor by
avoiding interferences and enhance the stability of the modifier
layer. The thickness of the electropolymerized polymers can be
easilycontrolledselectingtheelectropolymerizationconditions,and
redox properties can be modified by choosing a suitable dopant
molecule. In recent years, various nanomaterials have been used in
the construction of DNA biosensors. They are usually insoluble in
mostsolvents,buttheycanbeadvantageouslyentrappedwithinthe
polymer at the electrode surface. Moreover, composites of polymers
andnanomaterialsofferarangeofnewproperties,suchasenhanced
electron transfer, biocompatibility, and small dimensions with large
surface area, attractive for the miniaturizationof DNAbiosensors.
List of abbreviations
CHIT chitosan
CP conducting polymer
DNA deoxyribonucleicacid
