Biomedical Engineering Reference
In-Depth Information
(a) none
(b) 1nM
(c) 10nM
(d) 100nM
70
(d)
60
50
(c)
(b)
40
(a)
30
20
10
0
400
450
500
550
600
650
700
750
800
E vs. Ag/AgCl (mV)
Fig. 4.11.
Linear sweep voltammograms of Hoechst 33258 on gold electrodes at
different concentrations of DNA probes:
a
none;
b
1 nM;
c
10 nM;
d
100 nM
reacted with 100 nM target DNA at 100 mV/s. Electrode area 200
×
200
m
2
μ
considerable interest in developing reliable methods for single nucleotide po-
lymorphism analysis [5].
When we need to lower concentration of sample DNA, PCR amplifica-
tion of target DNA is effective. Recently, many methods for amplification
and detection of DNA, such as 5' nuclease assay [7] and electrophoretic ana-
lysis [8] on a microchip, have become available. These methods are based
on the phenomenon of fluorescence resonance energy transfer [9] (FRET), or
use intercalating dye for fluorescence detection, and there are few reports of
DNA amplification and electrochemical detection on a microchip. Therefore,
this section introduces a microfluidic PCR chamber and an electrochemical
detector.
Microchip Fabrication.
We designed integrated chips for electrochemical
PCR and gene detection. The structure of our chip is shown in Fig. 4.13.
This chips couples a PCR chamber with a chamber for electrochemical gene
detection, and provides on-chip DNA amplification and detection. The chip
was fabricated using standard micromachining techniques. The chip design
