Biomedical Engineering Reference
In-Depth Information
Figure 13.
(A) Schematic representation of the direct mode of SECM for the local-
ized electro-oxidative polymerization of pyrrole-oligonucleotide (ODN) probes. For
the copolymerization of pyrrole/pyrrole-ODN, solutions of 200 mM pyrrole/10 μM
pyrrole-ODN in LiClO4 (0.1M in water) were used. The potential applied was +0.7
V vs. Ag/AgCl and the polymerization time was 20 ms. The distance between the
substrate (gold) and the microelectrode used here as the counter electrode was 60
μm. (B) Schematic of the assembly process. The horseradish peroxidase
(HRP)-biocatalyzed oxidation of (
1
) in the presence of H
2
O
2
, and produces precipi-
tates of the insoluble product (
2
). (C)
Molecular Assembly
process. The detection of
the hybridization reaction of the ODN probes with their biotinylated complemen-
tary strands using SECM was possible after subsequent reactions with streptavidin
and biotinylated HRP. The insoluble product (
2
) precipitated on the Au film caused
a local alteration of conductivity, which can be sensitively detected by the SECM
tip and allowed imaging of DNA arrays in a fast and straightforward way. Reprinted
from Ref. 50. Copyright (2006). Reproduced by permission of the Royal Society of
Chemistry.
Search WWH ::
Custom Search