Biology Reference
In-Depth Information
Figure 14.17.
SchematicrepresentationoftheenhanceddetectionofDNA
hybridization based on a DNA-MWCNT sensor using daunomycin as the
electroactive indicator.
transfer between the electrode and intercalator, but also increased
the effectivearea of the electrode.
Hybridization events were also monitored by DPV measurement
of the reduction of intercalated daunomycin on a glassy carbon
electrode modified with MWCNTs and platinum nanoparticles
dispersed in Nafion [98]. Probe DNA was attached in a similar
manner through the formation of amide bonds between the -COOH
ontheMWCNTsand-NH
2
oftheoligonucleotides.Withtheaddition
of the Pt nanoparticles, the detection limit of this glassy carbon-
modified electrode to hybridized complementary DNA sequences
wasloweredbyanorderofmagnitudeto1.0
×
10
−
11
Mascompared
to that reported by Cai (1.0
×
10
−
10
M) using only MWCNT-
modified GCEs. Whereas CNTs promote electron-transfer reactions,
the nanoparticles further amplified the signal due to their high
catalytic activity toward daunomycin reduction.
He and Dai [86a] prepared aligned SWCNT-DNA sensors by
chemically coupling ssDNA probes on both the tip and wall of
plasma-activated aligned carbon nanotubes on gold electrodes.
