Biomedical Engineering Reference
In-Depth Information
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C
D
Figure 11.12
Binding and dissociation during PNA-DNA hybridization. Binding of different concentrations (in
m
M) of target DNA complementary to CYP2C9*2 (target DNA2) to CYP2C9*2 as a probe PNA
immobilized on a ion-sensitive field-effect transistor-based biosensor (
Uno et al.,2007
): (a) 5.
(b) 2.5. (c) 1. (d) 0.1. When only a solid line (--) is used then a single-fractal analysis applies.
When both a dashed (- - -) and a solid (--) line are used then the dashed line represents a single-
fractal analysis and the solid line represents a dual-fractal analysis.
k
1
and
k
2
, and the fractal dimensions,
D
f1
and
D
f2
, for a dual-fractal analysis, and (c) the dissocia-
tion rate coefficient,
k
d
, and the fractal dimension,
D
fd
, for the dissociation phase for a single-frac-
tal analysis are given in
Tables 11.7
and
11.8
. Note that for a dual-fractal analysis, as the fractal
dimension increases by 38.9% from a value of
D
f1
equal to 2.1140 to
D
f2
equal to 2.9360, the bind-
ing rate coefficient increases by a factor of 6.40 from a value of
k
1
equal to 43.465 to
k
2
equal to
278.35. Note that changes in the fractal dimension or the degree of heterogeneity on the sensor
chip surface and in the binding rate coefficient are in the same direction.
Figure 11.12b
shows the binding and the dissociation of 2.5
m
M target DNA concentration in
solution to the probe PNA immobilized on the sensor surface. Once again, a dual-fractal anal-
ysis is required to adequately describe the binding kinetics. A single-fractal analysis is ade-
quate to describe the dissociation kinetics. The values of (a) the binding rate coefficient,
k
,
and the fractal dimension,
D
f
, for a single-fractal analysis, (b) the binding rate coefficients,
