Biomedical Engineering Reference
In-Depth Information
Table 4.1
QDs ECL employed in the field of DNA biosensing
QD
−
1
)
Coreactant
Linear range (mol L
References
S
2
O
8
2
−
−
11
-1
×
10
−
15
5
×
10
CdTe
Hu et al. [
51
]
−
10
-5
×
10
−
15
CdTe
O
2
1
×
10
Deng et al. [
52
]
S
2
O
8
2
−
−
16
-5
×
10
−
18
CdS
1
×
10
Zhou et al. [
53
]
S
2
O
8
2
−
−
10
-5
×
10
−
18
CdS
1
×
10
Divsara and Ju [
54
]
S
2
O
8
2
−
−
6
-5
×
10
−
9
CdSe@ZnS
5
×
10
Huang et al. [
55
]
S
2
O
8
2
−
−
14
-10
−
19
CdTe@ZnO
10
Liu et al. [
56
]
S
2
O
8
2
−
−
6
-1
×
10
−
10
CdTe@SiO
2
2
×
10
Wei et al. [
57
]
−
11
-5
×
10
−
17
CdS:Eu
H
2
O
2
1
×
10
Zhou et al. [
58
]
S
2
O
8
2
−
−
17
-5
×
10
−
15
CdS:Mn
5
×
10
Shan et al. [
59
]
t-DNA concentration with a linear range of 5
×
10
−
15
-1
×
10
−
11
mol L
−
1
. Given
that the Cd-component QDs cytotoxicity could be caused by the release of heavy
metal ions and the instability in harsh environments, Liu et al. [
57
] synthesized the
CdTe@SiO2 composite through a reverse microemulsion method. The prepared
products not only retained high fluorescence intensity but also avoided cytotoxicity
due to the protection by the SiO
2
shell. DNA detection was realized by outputting
a remarkable ECL signal of the CdTe@SiO
2
labeled to the probe DNA with a low
detection limit of 0.03 nM and a wide dynamic range from 0.1 nM to 2 mM.
In the author's group, we [
55
] developed a simple and convenient assay with
QDs as the labels for DNA detection. Different from the common sandwich-type
strategy, in this system, the target DNA oligonucleotides are directly hybridized
with the probe DNA oligonucleotides for DNA detection, which reduces the
hybridization process, thus it is relatively simple and time-saving. After the QDs
bind to the target DNA via the biotin-avidin system, the DNA hybridization event
can be detected by ECL signal.
Table
4.1
shows the QDs ECL in DNA biosensing.
4.2.2 QDs ECL for Aptasensor Analysis
Aptamers are a new class of single-stranded DNA/RNA molecules, which are
selected from synthetic nucleic acid libraries via the selection procedure called sys-
tematic evolution of ligands by exponential enrichment (SELEX). Since first discov-
ered in 1990s [
60
,
61
], many aptamers have been selected for corresponding targets
combination ranging from metal ions, organic molecules, biomolecules, to entire
organism and even whole cells. Aptamers offer remarkable convenience in design and
modification of their structures, which has motivated them to generate a great variety
of aptamer sensors (aptasensors) that exhibit high sensitivity as well as specificity.
Based on the QDs ECL, a series of aptamer biosensors have been constructed
and applied for the detection of various targets ranging from small biomolecule to
entire cell, which were listed in Table
4.2
.
