Biology Reference
In-Depth Information
Figure 5.9.
Schematic illustration of miRNA assay using electrocatalytic
OsO
2
-NPs (adaptedfrom Ref. 42 with permission). See also Color Insert.
reported a linear relationship between current and concentration
from 0.3 to 200 pM microRNA with a measureable signal reported
for as low as 80 fM microRNA in 2.5 mL droplets following 60 min
hybridization. Successful attempts were made in the microRNA
expression analysis ofHeLa cells.
Additionally the assay can easily distinguish between a single
base mismatch, with a signal detected for fully matched microRNA,
and less than 25% signal reported for mismatched microRNA.
These results are comparable to the previous electrochemical
microRNA detection by this group [43], and offer many of the same
advantages over more conventional methods, such as PCR-based
and Northern blot techniques. The use of OsO
2
-NPs in preference
to the electrocatalytic moieties presented previously by this group
offersadditionaladvantagesfortheelectrocatalyticquantificationof
microRNA. These advantages include control over the choice of the
capping groups on the nanoparticle, which simplifies their ligation
tothemicroRNAandtheimprovedcatalyticeffectontheoxidationof
the hydrazine that results in improved signal. However, the authors
donotaddressthee
ciencyandreliabilityoftheconjugationofthe
nanoparticle tags to the microRNA [43].
5.4.3
Electrocatalytic Activity of Other Nanoparticles
Other non-metal particles have also been described as possible
catalysts in electroanalytical systems [13, 33]. For example, copper
oxide nanoparticles (CuO-NPs) of 5 nm size were mixed with
