Biomedical Engineering Reference
In-Depth Information
120
120
100
100
80
80
60
60
40
40
20
20
0
0
0
10
20
30
Time (min)
40
50
60
0
10
20
30
Time (min)
40
50
60
A
B
Figure 15.7
(a) Binding of 80 nM transcription factor (rhSP1) to rhNF-
B binding oligonucleotide on a
microcantilever array (
Huber et al., 2006
). (b) Binding of 100 nM transcription factor (rhNF-
k
B)
to SP1 binding oligonucleotide on a microcantilever array (
Huber et al., 2006
). 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
The biomoelcular recognition event of the binding of the ligand to the receptor on the surface
resulted in a bending of the microcantilever. This bending is detected by laser beam deflection.
Figure 15.7a
shows the binding of 80 nM transcription factor rhSP1 in solution to the cantilever
array functionalized with the binding oligonucleotide. A dual-fractal analysis is required to
adequately describe the binding kinetics. The values of (a) the binding rate coefficient
k
and the
fractal dimension
D
f
for a single-fractal analysis, and (b) the binding rate coefficients
k
1
and
k
2
and the fractal dimensions
D
f1
and
D
f2
for a dual-fractal analysis are given in
Table 15.5
.
It is of interest to note that as the degree of heterogeneity or the fractal dimension increases
by a factor of 1.58 from a value of
D
f1
equal to 1.3908 to
D
f2
equal to 2.2030, the binding
rate coefficient increases by a factor of 3.91 from a value of
k
1
equal to 12.367 to
k
2
equal
to 49.233. Once again, an increase in the degree of heterogeneity or the fractal dimension
on the cantilever array (biosensor) surface leads to an increase in the binding rate coefficient.
Figure 15.7b
shows the binding of 100 nM rhNF-
k
B transcription factor, in solution to the
cantilever array functionalized with the SP1 binding oligonucleotide. A dual-fractal analysis
is, once again, required to adequately describe the binding kinetics. The values of (a) the
binding rate coefficient,
k
and the fractal dimension,
D
f
for a single-fractal analysis, and
(b) the binding rate coefficients,
k
1
and
k
2
, and the fractal dimensions,
D
f1
and
D
f2
for a
dual-fractal analysis are given in
Table 15.5
.
It is of interest to note that as the degree of heterogeneity or the fractal dimension increases
by a factor of 1.27 from a value of
D
f1
equal to 2.3742 to
D
f2
equal to 2.8875, the binding
rate coefficient increases by a factor of 2.42 from a value of
k
1
equal to 13.708 to
k
2
equal
