Chapter 10 - Detection of Gases on Biosensor Surfaces

Abstract

The detection of different gases in the atmosphere is important for environmental awareness, air monitoring, and pollution control. Biosensors have been used to detect different gases in the environment and in the atmosphere. This chapter analyzes the detection of different gases in the atmosphere by biosensors and analyzes the kinetics of binding and dissociation (hybridization) in such biosensors through fractal analysis. Both single- and dual-fractal analyses are used to model the binding and dissociation kinetics of gases (including air pollutants) on biosensor surfaces. The fractal analysis is used to analyze the binding (and dissociation, if applicable) kinetics of the binding of liquid petroleum gas (LPG) to zinc oxide films prepared by the spray pyrolysis method onto a glass substrate, the binding and dissociation of different ammonia (NH3) concentrations in air to a sol-gel derived thin film biosensor, binding of NH3 in air to an optical fiber-based evanescent sensor, binding to an nc-Fe3O4/Si-NPA (nanocrystal magnetite/silicon nanoporous pillar array) humidity sensor, and the binding and dissociation of different methanol concentrations in ppm) to a polyimide thin layer biosensor. The distinct advantage of the fractal analysis method is that it provides binding and dissociation (if applicable) rate coefficient values and the fractal dimension, Df, or the degree of heterogeneity present on the biosensor surface. Furthermore, the analysis attempts to relate these binding and dissociation rate coefficients to the degree of heterogeneity present on the biosensor surface.