Biomedical Engineering Reference
In-Depth Information
Fig. 3.15
Schematic
illustration of miRNA
detection using a novel
fluorescence probe of
dsDNA-templated copper
nanoclusters as the signal
output, via the target-
triggered isothermal
exponential amplification
reaction. Reproduced with
permission from Ref. [
57
].
Copyright 2013, Royal
Society of Chemistry
testing with a rapid and simple “mix-and-measure” format. dsDNA-CuNCs can
be facilely prepared by reducing Cu
2
+
ions with ascorbic acid in the presence of a
DNA duplex within fifteen minutes. More importantly, the Cu
2
+
ions are soluble
in many detection environments and so have no precipitation phenomena like the
Ag
+
ions. Therefore, a facile label-free method for sensitive and selective detec-
tion of miRNAs using dsDNA-CuNCs as fluorescent reporters was developed
(Fig.
3.15
) [
57
]. In order to improve the analytical sensitivity, they have intro-
duced the target-triggered isothermal exponential amplification reaction (TIEAR)
to the proposed method. This amplification strategy has shown great potential
as the point-of-care testing with high amplification efficiency under a constant
temperature.
3.2.4 Sensing Based on Fluorescence In Situ Hybridization
In situ detection of RNAs is becoming increasingly important for analysis of gene
expression within and between intact cells in tissues. Fluorescence in situ hybrid-
ization (FISH) of nucleic acid-labeled probes provides a direct visualization of
the spatial location of specific DNA or RNA sequences at a particular cellular
or chromosomal site and in tissue sections [
58
]. Streptavidin-labeled/biotinylated
