Biology Reference
In-Depth Information
Figure 5.6.
Schematic representation of the electrochemical DNA detec-
tion using the catalytic and electrocatalytic oxidation of NaBH
4
on Pd-NP
labels onto ITO electrodes and the rapid enhancement of electrocatalytic
activity of DNA-conjugated Pd-NPs (adapted from Ref. 37 with permission).
See also Color Insert.
similar work with Au-NPs as electrocatalytic labels [11], they
recently reported Pd-NPs, activated by NaBH
4
, as ideal electrocat-
alytic labels for DNA detection (Fig. 5.6) that work even at high
pH levels with reduced incubation time. The high pH is necessary
in order to avoid the self-hydrolysis of NaBH
4
at lower values,
even though the catalytic hydrolysis of NaBH
4
can be slower at
this pH. The resulting sensor achieved an LOD of 10 aM (BRCA1
associated gene sequence) with a detection range of 10 orders
of magnitude, using an ITO electrode as substrate and following
the hybridization process by linear sweep voltammetry. The rapid
enhancement comes from the fast catalytic hydrolysis of NaHB
4
onto Pd-NPs' surfaces and subsequent fast hydrogen sorption into
Pd-NPs. The electrocatalytic activity of DNA-conjugated Pd-NPs
allows high currents for the electro-oxidation within the potential
windows.
5.4 Catalysis Induced by Other Nanoparticles
5.4.1
Electrocatalytic Activity of Titanium Dioxide
Nanoparticle Labels
Metal oxides are emerging as important materials because of their
versatile properties such as high-temperature superconductivity,
