Biology Reference
In-Depth Information
Table4.2. Goldnanoparticle-basedelectrochemicalDNAbiosensorsusing
enzymatic detection
Modified Electrode
Detection
Analyte
Substrate
Technique
Detection Limit Reference
×
10
−
11
M
Synthetic DNA strands
CPE
DPV
5.0
41
1.3
μ
M
H
2
O
2
AuE
CV Chronoam-
42
perometry
Salmonella
sp.
nanoAu-GEC
Amperometry
9 fmol(60 pM)
39
Synthetic
Au/SPE
Amperometry
-
43
oligonucleotides
Synthetic 30-mer
SPCE
CV
2.5 pmol/L
40
oligonucleotides
Au/SPE: goldscreen-printed electrode; nanoAu-GEC: nanogold graphite-epoxy composite.
step a series of compounds exhibiting a significant difference in
their voltammetric signals in the presence of ssDNA or dsDNA. Du
et al.
[44] recently fabricated a DNA biosensor by the sequential
modification of gold electrodes with Au-NPs and CdS-NPs. The
modified electrode was applied for the detection of target DNA with
Co(phen)
2
2
+
as hybridization indicator. The target DNA sequence
was quantified over the range 2.0
10
−
10
to 1.0
10
−
8
M, with
×
×
a detection limitof 2.0
×
10
−
11
M.
In a similar methodology, methylene blue (MB) has recently
been used as electrochemical indicator for the preparation of an
adenosine triphosphate (ATP) aptasensor [45]. Au-NPs claimed to
make more MB interact with DNA on the sensing interface. The DPV
peak current corresponding to the MB oxidation decreased with
ATP concentration in the 1
×
10
-
10
Mto1
×
10
-
7
M range, with a
detection limit of 0.1 nM. The sensor showed advantages regarding
low-cost, rapidity, simple detection, andreusability.
Intercalated doxorubicin has been also used as an electro-
chemical label in the detection of DNA hybridization events
in a genosensor built by layer-by-layer covalent attachment of
multiwalled carbon nanotubesand Au-NPs[46]. The oxidation peak
current obtained by differential pulse voltammetry showed a linear
relationship with the logarithm of the target DNA concentration in
the range 5.0
10
−
10
to 1.0
10
−
11
M, with a detection limit of
×
×
6.2 pM.