Biomedical Engineering Reference
In-Depth Information
12
10
8
6
4
2
0
50
200
0
100
Time (min)
150
Figure 14.3
Binding and dissociation of 0.88 mM hydrogen peroxide mixed with LB (Luria-Bertani) medium to
GC2 (Escherichia coli strain) immobilized microcell chips (
Yoo et al., 2007
).
Table 14.2: Binding and dissociation rate coefficients and fractal dimensions for the binding and
the dissociation phase for 0.88
M hydrogen peroxide mixed with LB (Luria-Bertani) medium in
solution to the GC2 immobilized microcell chips (
Yoo et al., 2007
).
m
Analyte in Solution/Receptor on Surface
k
k
d
D
f
D
fd
0.88
m
M hydrogen peroxide
þ
LB medium 0.3248
0.1097
0.0203
0 1.400
0.1272 0.168
0
In this case, the affinity, K (¼ k/k
d
) value is equal to 16.06.
Anaissi and Toma (2005)
have developed a catechol incorporation and detection method
using bentonite-vanadium (V) oxide xerogels. Catechol (a derivative of phenol) is a water
pollutant, and
Anaissi and Toma (2005)
point out that in aqueous solution the electrochem-
istry is complicated by secondary reactions (
Papouchado et al., 1972, 1975; Ryan et al.,
1980
).
Anaissi and Toma (2005)
report that due to the above complications biosensors are
currently being used to detect catechols in aqueous solution (
Cosnier et al., 1998
,
2001;
Rodriguez and Rivas, 2002; Kim and Lee, 2003; Timur et al., 2004
).
Anaissi and Toma
(2005)
have analyzed the intercalation of catechol into bentonite-vanadium (V) oxide
xerogels (BV), and have characterized the resulting material electrochemically and
spectroscopically.
Anaissi and Toma (2005)
point out that for dilute solutions (e.g., less than 10
4
mol/dm
3
) the
intercalation process proceeds slowly. These authors monitored the kinetics (of binding of
catechol in solution to the BV optode) spectrophotometrically by measuring the absorbance
at 660 nm versus time.
Figure 14.4
shows the incorporation of 7.8
10
5
mol/dm
3
catechol
in solution and its detection using bentonite-vanadium (V) oxide xerogels. A dual-fractal
analysis is required to adequately describe the binding kinetics. The values of (a) the binding
