Biomedical Engineering Reference
In-Depth Information
Table 7.9: Binding of 500 mM glucose in solution (sequential addition every 100 s) to the
microelectrodes under stirred conditions.
Applied
Potential (V)
k
k
1
k
2
D
f
D
f1
D
f2
0.0)10
10
2.0)10
14
0.3
(2.0
na
na
(1.0
na
na
0.3)10
9
0.4)10
10
0.1)10
8
0.4
(1.2
(1.7
(3.5
1.0574
0.394
1.9930
0.2298
0.351
0.1754
0.2)10
8
0.5
(2.0
na
na
1.6514
na
na
0.0828
Influence of varied applied potentials (
Pemberton et al., 2009
).
Figure 7.13b
shows the hydrodynamic voltagram (binding kinetics) at an applied potential of
0.4 V (
Pemberton et al., 2009
). 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 7.9
.
It is of interest to note that as the fractal dimension increases by a factor of 5.06 from a
D
f1
value equal to 0.394 to
D
f2
equal to 1.9930, the binding rate coefficient increases by a factor
of 206 from a value of
k
1
equal to 1.7
10
8
. Once again, an increase in
the degree of heterogeneity or the fractal dimension on the microband sensor surface leads to
an increase in the binding rate coefficient.
10
10
to
k
2
equal to 3.5
Figure 7.13c
shows the hydrodynamic voltagram at an applied potential of 0.5 V. A single-
fractal analysis is adequate to describe the binding kinetics. The values of (a) the binding rate
coefficient,
k
, and the fractal dimension,
D
f
, for a single-fractal analysis is given in
Tables 7.9
.
7.4 Conclusions
This chapter has concentrated on and presented different examples for the detection of glu-
cose in solution by different biosensors available in the literature. The kinetics of binding
and dissociation (wherever applicable) were analyzed using fractal analysis. As indicated
in the beginning of the chapter the detection of glucose in solution was, in a way, the first
application that led to the development of biosensors. Over the years more and more sophis-
ticated biosensors have been developed for the detection of glucose in keeping with the cur-
rent trends in research, such as nanotechnology and nanobiotechnology. The ease of use of
biosensors has led to the application of biosensors in different areas such as the detection
of pollutants in the environment and pathogens in the early onset of diseases, in biological
warfare detection, detection of explosives for aircraft and passenger protection, food preser-
vation and spoilage, etc.
