Biology Reference
In-Depth Information
and 2-aminoanthracene (0.001-6 ppm) [52]. A similar DNA biosen-
sor was also used for the detection of organophosphates such
as chlorpyrifos and malathion up to 0.0016 ppm and 0.17 ppm,
respectively [53].
Becauseofthenegativecharge,ODNcanalsoserveasadopantof
Ppy. A Ppy-ODN film was prepared at the surface of gold electrode
for genoelectronic application [54]. It was found that the redox
activityofthebiosensorwasaffectedbypresenceofODNmolecules
and it was able to discriminate between synthetic oligonucleotides
and chromosomal DNA. Komarova
et al.
[55] prepared the DNA
biosensoratthesurfaceofITOelectrodeselectrochemicallyfromthe
solution containing Py and ODN. ODN served as a sole dopant, and
a prepared biosensor was used for chronoamperometric detection
of the target ODN with the detection limit of 1.6 fmol in 0.1
ml. An ssDNA/polypyrrole-modified electrode for the detection
of specific bovine leukemia virus provirus DNA sequences was
prepared [56]. In this case, Ppy was electrochemically doped with
ssDNA in the presence of KCl, which eliminated a nonspecific
contribution. A Ppy film doped with oligonucleotide probe was
also formed at the surface of microelectrodes in the presence
of LiClO
4
in order to prepare an impedance DNA hybridization
biosensor [57]. The biosensor was applied for the detection of
nanomolar concentrations of target ODN at the silicon array chip
containing four gold microelectrodes. The Ppy-ODN film was
also electropolymerized at the surface of Au electrode from the
solution containing pyrrole, ODN, and NaCl by continuous cyclic
voltammetry [43, 58]. An electrode was used for the detection of
DNAhybridization.AthinfilmofPpydopedwithanODNprobewas
electropolymerizedatthesurfaceofgoldmicroelectrodesintegrated
on the chip and used for sensing electrical potential-assisted DNA
hybridization and pathogen target DNA detection [59]. Detection of
0.34 pmol and 0.072 fmol of complementary ODN target in 0.1 mL
within a time of seconds were achieved on unpolished and polished
electrodes, respectively.
Another approach was described by Livache
et al.
[60]. Pyrrole
was first functionalized by ODN using pyrrole-phosphoramidite
building blocks. Next, Ppy copolymer was prepared by electropoly-
merizationinthesolutioncontainingpyrroleandpyrrole-ODN.This
