Explorations and Applications of Novel Sensing Approaches –Wireless Sensing Systems

Abstract

The aim of this dissertation is to explore novel sensing approaches and their applications in the detection of alcohol, the investigation on reactions between antibodies and antigens, as well as the studies of visually rechargeable batteries by combining electrochemical, especially bipolar electrochemical, technique with other chemical and analytical chemical techniques. To detect alcohol, a novel enzyme catalytic alcohol sensor has been fabricated with MWCNT, NAD+, ADH and PDDA immobilized on one end and Ru( bpy)33+/Nafion coated on the other end of a platinum bipolar electrode based on the principles of bipolar electrochemistry and electrochemiluminescence. The amount of current flowing through the bipolar electrode is proportional to the concentration of alcohol and can be monitored using electrogenerated chemiluminescence (ECL) from the Ru(bpy)33+/Nafion coated cathodic pole. Magnetostrictive particles (MSPs) expand when exposed to a magnetic field, exhibiting the Joule Effect or Magnetostriction. By monitoring the reactions between antibodies and antigens that take place on the surfaces of Au-modified MSPs placed in a magnetic field, the reaction association constant can be achieved. The experimental results indicate the high affinity of antibody-antigen binding reaction. The surface functionalization of Fe-based materials is a crucial issue because it not only protects Fe-based materials from corrosion but also broadens the application of Fe-based materials. In this work, alkane phosphonate SAMs formed on Fe and MSPs surfaces are used to build a multifunctional sensor platform, using which, people can detect two different things on one sensor. In other words, the functionality of sensors will be improved greatly. Polyaniline is a conductive polymer that has different colors which correspond with different oxidation states. In light of this property, polyaniline can be utilized as electrochromic materials. A bipolar electrode with polyaniline modified on one end and Ag on the other end can act as a rechargeable battery. The processes of charge and discharge can be observed visually through the color change. In order to fulfill the miniaturization of experiments, a simple method for making Au microarray electrodes was discussed and the batteries fabricated on a microarray were characterized via photography, linear sweep voltammetry and Raman spectroscopy.