Conducting Polymer Based Enzyme Electrodes Fabricated by Invertase and Polyphenol Oxidase

Abstract

Novel carbon fiber enzyme electrodes were constructed and evaluated. Fabrication of electrodes was performed via electrochemical deposition of a conducting matrice composed of polythiophene and polypyrrole (PTh–PPy) onto carbon fiber substrates. The enzyme was entrapped into the matrix during electropolymerization. Resultant biosensors represented higher kinetic parameters, Vmax and Km, in comparison to PPy matrice, which are 2.471 ± 0.150 mol min1- electrode1- and 30.60 ± 5.30 mM for invertase, 0.056 ± 0.012 mol min1- electrode1- and 842.00 ± 37.50 mM for polyphenol oxidase respectively. Optimum pH and temperature of the immobilized enzyme within PTh–PPy composite indicates that this matrice provides a more protective environment. The detection limit (LOD) of polyphenols was obtained as 0.037 mg mL1-. Polyphenol oxidase enzyme electrodes were proved to be used for the determination of polyphenolic substances in real samples and the results were confirmed by the Folin-Ciocalteau method