Biomedical Engineering Reference
In-Depth Information
CHAPTER 10
Detection of Gases on Biosensor Surfaces
Chapter Outline
10.1 Introduction
255
10.2 Theory
256
10.2.1 Single-Fractal Analysis
256
Binding Rate Coefficient
256
Dissociation Rate Coefficient
257
10.2.2 Dual-Fractal Analysis
257
Binding Rate Coefficient
257
10.3 Results
258
10.4 Conclusions
292
10.1 Introduction
The detection of different (at least, the harmful ones) gases in the atmosphere is important
for environmental awareness and pollution control. For example
Cao and Duan (2005)
report
that the accurate detection of near real-time monitoring of gaseous ammonia has wide
applications in environmental science and occupational inspection. These authors draw atten-
tion to the presence of ammonia in the atmosphere as a potential hazard for human beings
and ecosystems.
Tsai et al. (2007)
have recently pointed out that there is increasing concern
about global climate change and air pollution. Thus, a lot of attention has been paid to using
hydrogen as a clean energy source. Hydrogen fuel cells exhibit significant potential for
many applications. However,
Tsai et al. (2007)
warn that hydrogen mixed with oxidants
may cause explosions. Thus, there is a critical need to develop a hydrogen sensor for the con-
tinuous monitoring of hydrogen gas concentrations in air.
Tsai et al. (2007)
report that the
rapid advances in fabrication and growth technologies have permitted many metal-oxide-
semiconductor (MOS) structures to be used as hydrogen sensors including the catalytic metal
and different semiconductor materials (
Diwedi et al., 2000; Chen et al., 2002; Lu et al., 2003;
Medlin et al., 2003
).
The above were just a few examples wherein biosensors have been used to detect gases in the
atmosphere. In this chapter we use fractal analysis to analyze the binding and dissociation
(if applicable) kinetics of (a) the binding of liquid petroleum gas (LPG) to zinc oxide films
