Biology Reference
In-Depth Information
12.5.2.2 Compound-based detection (indirect redox
indicator-based detection)
The compound-based electrochemical detection studies for
chemical-DNA interactions start with the identification of redox
potentials of related compounds by using cyclic voltammetry in
general. The redox peak potential of guanine (
+
1.0V) [9] is also
evaluatedbyobtainingcompoundpeaksifbothDNAandcompound
signals don't lie in the same peak position in the voltammogram.
Total evaluations are performed with the results of bare and DNA-
modified surfaces together based on both DNA and compound
signals.
In some promising applications about compound-DNA inter-
actions, these molecules can be found as a “DNA hybridization
indicator” because of their different binding behaviors to dsDNA
or ssDNA [59, 60]. This knowledge provides the development of
new drugs and DNA sensors which will further become microchip
devices. Indicator-based electrochemical DNA biosensors contains
electroactive compounds such as methylene blue (MB) [61],
ferrocenylnapthalene diimide [62], several metal complexes such
as cobalt phenanthroline [20], osmium, and ruthenium [63]. In
other applications, Kelley
et al.
[64] and Boon
et al.
[57] used
electroactive intercalators which noncovalently bound to DNA for
the detection of different kinds of single-base nucleotide changes.
Some redox-active DNA markers such as ferrocene [65], amino
and nitro-phenyl tags [66], tris-bipyridine complexes of osmium
or ruthenium were applied by
Fojta et al.
[67] for the detection
of SNPs (single nucleotide polymorphisms). Furthermore, carbon-
based transducers have also been used with several noncovalent or
covalent bindinglabelson DNA [2, 61, 68].
Panke
et al.
[69] performed a different approach related to a
competitive binding protocol for the determination of DNA single
base mismatches by using methylene blue in combination with
differential pulse voltammetry technique. Duwensee
et al.
[70]
reported a strategy for sequence-specific DNA detection by means
of a competitive hybridization assay with osmium tetroxide-labeled
signalingprobes.
