Biomedical Engineering Reference
In-Depth Information
0.1
0.1
0.1
0.0
0.0
0
0
2
4
6
8
Time (s)
10
12
14
16
Figure 6.6
Binding and dissociation of 0.1 ng/ml
-fetoprotein (AFP) in solution to capture antibody on a
fiber-optic biosensor surface (
Chang et al., 2008
).
a
It is of interest to compare the binding and dissociation rate coefficients and the
corresponding fractal dimension values for the binding and dissociation of AFP in solution
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PIP to the double-codified gold nanoparticles labels modified by HRP-conjugated anti-
AFP (
Yang et al., 2009
) with the binding and dissociation of 0.1 ng/mL AFP to the anti-
AFP immobilized on a SPR biosensor surface (Chang et al., 2005). Note that in both of these
cases a dual-fractal analysis is required to adequately describe the binding kinetics, whereas
the dissociation kinetics may be described by a single-fractal analysis.
It is noteworthy that as one goes from the binding of AFP in solution to anti-AFP
immobilized on a SPR biosensor surface (Chang et al., 2005), to the binding of AFP in solu-
tion with PIP to the double-codified HRP-conjugated anti-AFP (
Yang et al., 2009
) the fractal
dimension,
D
f1
, decreases by a factor of 2.62 from a value of
D
f1
equal to 1.2632 to
D
f2
equal
to 0.4828 for a dual-fractal analysis. The binding rate coefficient,
k
1
, decreases by a factor of
18.14 from a value of
k
1
equal to 0.3367 to 0.01856. However, in this case as the fractal
dimension,
D
f2
, increases from a value of 0.0 to 1.2752 as one goes from the binding of
AFP in solution to the anti-AFP immobilized on a SPR biosensor surface (Chang et al.,
2005) to the binding of AFP in solution with PIP to the double-codified gold nanoparicle
(DC-AuNP) labeled modified HRP-conjugated anti-AFP, the binding rate coefficient,
k
2
,
increases by a factor of 313273 from a value of
k
2
, equal to 0.000886 to
k
2
equal to 277.56.
This is a substantial increase of more than five orders of magnitude. This is because the fractal
dimension on the SPR biosensor surface was 0.0, which represents a Cantor-like dust.
As one might very reasonably expect, quite a lot of effort has been spent on the detection of
glucose in solution. Some of the more recent biosensors that have been used to detect glucose
in solution include:
