Binding and Dissociation Kinetics of Different Analytes on Novel Biosensing Surfaces: A Fractal Analysis - Biosensors and Biosensor Kinetics - page 357

6

5

4

3

2

1

0

0 200 400 600

Time (s)

800 1000

Figure 12.11
Binding of H9 avian influenza virus to cadmium quantum dots (Yun et al., 2007).

Yun et al. (2007) recently used cadmium telluride quantum dots as a proton flux sensor to
detect the H9 avian influenza virus. Figure 12.11 shows the binding of the H9 avian influenza
virus to the cadmium telluride quantum dot sensor. A single-fractal analysis is adequate to
describe the binding kinetics. The values of the binding rate coefficient, k , and the fractal
dimension, D f , for a single-fractal analysis are given in Table 12.6 .

Sauvage et al. (2007) recently pointed out the need for new sensor devices that can monitor
ions, especially for fundamental studies in medicine. They report that, for example, sodium
ions play a major role owing to their importance in the metabolism of the human body.
They explain that sodium ion concentration plays a major role in blood pressure regulation,
efficient muscle movement, and in the functioning of nerves. They also pointed out that
various strategies are underway to help develop sensible, selective, and reproducible sodium
ion sensors.

Kanoh et al. (1993) have reported the use of insertion materials for sensing purposes.
Sauvage et al. (2004) used olivine-type LiFePO 4 insertion material for use as a good candi-
date for a Li-ion sensor. Tani and Umezawa (1998) used Na 0.44 MnO 2 as a suitable material
for a Na-type ion sensor. This material has the ability to reversibly accommodate lithium ions
( Doeff et al., 1994, 1995 ). Sauvage et al. (2007) attempted to define the synthesis parameters
for the formation of Na 0.44 MnO 2 , and then analyzed the potentiometric properties of this
material towards sodium ions.

Figure 12.12 shows the open current voltage measurements (binding kinetics) using a
Na 0.44 MnO 2 /C plastic composite electrode recorded in 1 M NaNO 3 concentration at 30 C.
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 analy-
sis, 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 12.6 .