Biology Reference
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(MB) as hybridization indicator in many researches. MB is an
aromatic heterocycle; although MB is an organic dye molecule and
an intercalating agent, it has a higher a
nity to guanine bases
[55]. Enescu
et al.
[56] investigated the conformation of MB-
guanine complex by molecular dynamics simulation. The position
andorientationofMB-guaninecomplexeswerefoundtobeinthree
modes: T-shaped, non-stacked and face to face. Due to this a
nity,
weused MB as a hybridizationindicator in several works.
Early studies with MB were performed by Barton [57] as
intercalator molecule. In 2000, our group used MB for the first time
as a hybridization indicator which has a strong a
nity to guanine
[58]. In this study, 21-mer oligonucletotides related to Hepatitis
B virus (HBV) were immobilized onto CPE and hybridization was
detected after MB accumulation. Voltammetric transduction of MB
reduction was monitored. The comparison of indicator behaviors
between intecalator molecule ruthenium complex and MB was
performed in 2001 [59]. Calf-thymus dsDNA and ssDNA were
immobilized onto CPE electrostatically. CV and DPV transduction of
hybridizationindicators were monitored after accumulation.
Figure 13.3 represents the voltammetric detection of hybridiza-
tioninthepresenceofMBhybridizationindicator.DuetostrongMB
a
nity,voltammetricpeakofMBafteraccumulationwith(a)ssDNA
issignificantly higher to (b) bare electrode, and (c) sDNA.
The effect of ionic strength onto MB accumulation behavior
was also studied by our group [60]. Chronocoulometric and
voltammetric parameters for MB on binding to DNA at CPE were
monitored.Itwasfoundthat10mMionicstrengthisthecriticalsalt
concentration.MBinteractstoguanineelectrostaticallyupto10mM
NaCl,inthepresenceofhigherconcentrationsof10mMofNaCl,MB
intercalates to hydrogen boundsof dsDNA.
Hybridization and one-base mismatch detection was performed
by using self-assembled monolayer (SAM) on gold electrodes
in the presence of MB indicator first time [61]. 14-mer short
oligonucleotides were immobilized onto Au electrode surface by
usingalkanethiolmonolayercouplingatsurface.Mercaptopropionic
acid (MPA) was used for monolayer production. Voltammetric
reduction signal of MB was monitored for hybridization and
mismatch detection.
