Biomedical Engineering Reference
In-Depth Information
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) indicates that in both these cases a dual-fractal
analysis is required to adequately describe the binding kinetics, and the dissociation kinetics
may be described by a single-fractal analysis.
As one goes from the binding of AFP in solution to anti-AFP immobilized on a SPR biosen-
sor surface (Chang et al., 2005), to the binding of AFP in solution 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
f1
equal to 0.4828 for a dual-frac-
tal 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. It must be noted, however, that in this case as the fractal dimen-
sion,
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-AuNPs)
labeled modified HRP-conjugated anti-AFP, the binding rate coefficient,
k
2
, increases by a
factor of 31327 from a value of
k
2
equal to 0.000886 to
k
2
equal to 277.56. This is a substan-
tial increase of more than five orders of magnitude. This is because the fractal dimension on
the SPR biosensor surface was equal to 0.0, which represents a Cantor-like dust.
(4) A novel biosensor using a modified GCE for the detection of glucose (
Sheng et al.,
2008
), the binding of glucose in solution to the electroless plated Au/Ni/copper low
electrical resistance electrode (
Lee et al., 2008
), the long-term stability of a glucose bio-
sensor based on the insertion of barrel plating gold electrodes (
Hsu et al., 2009a,b,c
),
and a percutaneous fiber-optic sensor for chronic glucose monitoring
in vivo
(
Liao
et al., 2008
).
A comparison of the binding of glucose in solution to the neodymium hexacyanoferrate nano-
particle on the glucose oxidase/chitosan-modified GCE (
Sheng et al., 2008
) with that of the
binding of 1-53 mM glucose in solution to the electroless-plated Au/Ni/copper low electrical
resistance electrode (
Lee et al., 2008
) indicates that in the first case a dual-fractal analysis
is required to adequately describe the binding case presented. In the second case, a single-
fractal analysis is adequate to describe the binding kinetics for all the three concentrations
of glucose (21, 27, and 53 mM) analyzed. In the first case, a complex binding mechanism
is involved since a dual-fractal analysis is required to adequately describe the binding kinet-
ics, whereas in the second case a simple binding mechanism is involved since a single-fractal
analysis is adequate to describe the binding kinetics. Also, in the second case, even though
the fractal dimension or the degree of heterogeneity on the biosensor surface,
D
f
, equal to
2.8850, 2.9788, and 3.0 are higher than those in the second case for the second phase
(
D
f2
equal to 2.604), the binding rate coefficient,
k
, for the second case is lower than the
binding rate coefficient,
k
2
. This is due, of course,
to the different biosensor systems
involved.
