Biomedical Engineering Reference
In-Depth Information
12
10
8
6
4
2
0
0
10
20
30
Time (min)
40
50
60
Figure 15.1
Binding of 5.0 ng/ml carcinoembryonic antigen (CEA) in glucose using enzyme-catalyzed deposition
of a redox polymer and electrolytic oxidation of ascorbic acid (AA;
Gao et al., 2009
).
Figure 15.1
shows the binding of 5.0 ng/ml CEA in glucose/PVIA-Os solution (
Gao et al.,
2009
). The authors report that PVIA gave the highest redox polymer loading amongst
the polymer backbones. PVIA-Os is PVIA complexed with [Os(bpy)(tpy)]
2
þ
/3
þ
. A single-
fractal analysis is adequate to describe the binding kinetics. The values of the binding rate
coefficient
k
and the fractal dimension
D
f
for a single-fractal analysis are given in
Table 15.1
.
Wang et al. (2006)
have recently defined a biomarker as, “a characteristic that is measured
and evaluated objectively as an indicator of normal biological processes, pathogenic pro-
cesses, or pharmacologic responses to a therapeutic intervention.” TNF-
a
is a biomarker that
Table 15.1: Binding rate coefficient and fractal dimension for the binding phase for the detection
of different biomarkers by an electrochemical immunoassay (EIA): (a) carcinoembryonic antigen
(CEA) using enzyme-catalyzed deposition of a redox polymer and electrolytic oxidation of
ascorbic acid (AA;
Gao et al., 2009
), (b) tumor necrosis factor-
) using poly(guanine)
functionalized silica nanoparticles (NPs;
Wang et al., 2006
), and (c) thrombin using
aptamer-based assay coupled to magnetic beads and anti-thrombin to immobilized biotinylated
thrombin (
Centi et al., 2008
).
a
(TNF-
a
Analyte in Solution
k
D
f
References
5.0 ng/ml CEA in glucose/PVIA-OS
0.2451
0.0158
1.132
0.0840
Gao et al. (2009)
1.0 ng/ml TNF-
in 0.1M PBS buffer
containing Ru(bpy)
3
Cl
2
2.360
0.325
1.8350
0.3268
Wang et al.
(2006)
a
400 ppm IgG antithrombin to immobilized
biotinylated thrombin
81.24
1.40
2.3794
0.0137
Centi et al. (2008)
20 nM thrombin to immobilized biotinylated
aptamer
9.879 0.474
1.5386 0.0364
Centi et al. (2008)
