25
2.3.4.2 Nucleic Acid Detection
Liang et al. utilized QDs to miRNA microarray assays by using streptavidin QDs
probes to label biotinylated miRNA targets derived from rice, as shown in Fig. 2.10
[52]. Initially, miRNAs were oxidized with sodium periodate to oxidize the ribose
2′- and 3′- hydroxyl groups into aldehydes. The resulting dialdehyde was then
reacted with biotin-X-hydrazide resulting in biotinylated miRNA. This was followed
by immobilizing the 5′ amine-modified oligonucleotide probes antisense to miRNAs
on the amine-reactive glass slides. The biotinylated miRNAs were captured on the
microarray by oligonucleotide probes in hybridization. QDs were labeled on the
captured miRNAs through the strong specific interaction of streptavidin and biotin.
Since the QDs have a high extinction coefficient and quantum yield, so tiny amounts
of miRNAs can be detected easily with a laser confocal scanner. In addition, as an
alternative, the colorimetric gold–silver detection method was used in which
captured miRNAs were labeled with streptavidin-conjugated gold followed by
silver enhancement. During silver enhancement, the gold nanoparticles bound to
Fig. 2.9 QD multiplexed
biosensing. (Adapted from
Ref. [53])
2 Detection of Biological Warfare Agents Using Biosensors
2.3.4.2 Nucleic Acid Detection
Liang et al. utilized QDs to miRNA microarray assays by using streptavidin QDs
probes to label biotinylated miRNA targets derived from rice, as shown in Fig. 2.10
[52]. Initially, miRNAs were oxidized with sodium periodate to oxidize the ribose
2′- and 3′- hydroxyl groups into aldehydes. The resulting dialdehyde was then
reacted with biotin-X-hydrazide resulting in biotinylated miRNA. This was followed
by immobilizing the 5′ amine-modified oligonucleotide probes antisense to miRNAs
on the amine-reactive glass slides. The biotinylated miRNAs were captured on the
microarray by oligonucleotide probes in hybridization. QDs were labeled on the
captured miRNAs through the strong specific interaction of streptavidin and biotin.
Since the QDs have a high extinction coefficient and quantum yield, so tiny amounts
of miRNAs can be detected easily with a laser confocal scanner. In addition, as an
alternative, the colorimetric gold–silver detection method was used in which
captured miRNAs were labeled with streptavidin-conjugated gold followed by
silver enhancement. During silver enhancement, the gold nanoparticles bound to
Fig. 2.9 QD multiplexed
biosensing. (Adapted from
Ref. [53])
2 Detection of Biological Warfare Agents Using Biosensors