Enzyme kinetics and electrochemical polymer transistor detection of enzyme reactions

Astier, Yann (2001) Enzyme kinetics and electrochemical polymer transistor detection of enzyme reactions. University of Southampton, Doctoral Thesis.

Record type: Thesis (Doctoral)

Abstract

The aim of the research reported in this thesis is to adapt the polymer microelectrochemical transistor technology to in-vitro immunological detection. In-vitro immunological detection or immunoassay is a routine diagnostic tool in medicine.

A wide variety of mono-specific antibodies can be obtained commercially with alkaline phosphatase attached as a label, consequently we describe a sensor offering a rapid detection (less than 60 s) of very low alkaline phosphatase concentrations (0 to 4 nM). We show how a poly(aniline) transistor may be switched from conductive to insulating by a redox enzyme. We show that this is still true when the polymer transistor is physically separated from the enzyme reaction in a chemical battery set-up. This set-up enabled us to use different pH conditions in both compartments of the battery like eletrochemical device. Our sensor retains the polymer transistor electrochemical properties in acid while alkaline conditions are used in cell B. Electron transfer reaction from p-aminophenol at pH 9 in cell B poly(aniline)-poly(vinylsulfonate) in 2M sulfuric acid (cell A) is obtained, resulting in a change of polymer potential and hence a change of polymer conductivity. Also we describe the fabrication of 70 similar polymer transistors designed for one off detection experiments. We present a detailed account of p-aminophenol electrochemical properties above pH 7.

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