Christine Mousty

A composite poly azure B /clay /enzyme sensor for the mediated electrochemical determination of phenols

Abstract The biosensor construction is based on the entrapment of polyphenol oxidase (PPO) within a laponite clay film coated on an underlying poly azure B film (PAB) modified electrode. The amperometric detection consists in the electrochemical reduction of o -quinone, the product of the PPO reaction. Upon oxidative electropolymerization of azure B in aqueous electrolyte, an electroactive PAB is formed on the electrode surface. This underlying poly azure B film acts as a highly efficient electron shuttle between the cathode and the enzymatically generated o -quinone. The resulting composite PAB/PPO–laponite biosensor enabled the direct determination of 4 nM ( −1 ) phenol, 0.4 nM (0.05 μg l −1 ) p -cresol and 0.2 nM (0.02 μg l −1 ) m -cresol in batch mode. Linearity of response over four orders of magnitude was achieved.

HRP Wiring by Redox Active Layered Double Hydroxides: Application to the Mediated H2O2 Detection

Abstract With the aim of amperometric biosensor development, enzymes were immobilized within layered double hydroxides (LDH), also called anionic clay. Synthetic redox active [Zn–Cr–ABTS] LDH is used as an immobilization matrix for HRP in order to perform the electrical wiring of the enzyme. The electrochemical transduction step corresponds to the reduction at 0.0 V of the intercalated ABTS+ ·, enzymatically formed in the presence of H2O2. The HRP/[Zn–Cr–ABTS] biosensor sensitivity and detection limit are 443 mA M−1 cm−2 and 10 nM, respectively. The co-immobilization of GOx with HPR at [Zn–Cr–ABTS] coating gives rise to a bienzymatic electrode applied to the determination of glucose at 0.0 V.

Fabrication of organic phase biosensors based on multilayered polyphenol oxidase protected by an alginate coating

Abstract We describe herein, the creation of an organic phase enzyme electrode (OPEE) via avidin–biotin interactions built over an electrogenerated polymer. Multilayered polyphenol oxidase (PPO) assemblies were transferred into an organic solvent (chloroform) for the catechol detection at −0.2 V. In conjunction with an alginate gel, as a hydrophilic additive, the biosensor performance was widely enhanced. The effects of biotinylated polypyrrole film and alginate gel on the diffusion process through the biosensor coating are studied by rotating disk electrode experiments carried out in chloroform with hydroquinone as electroactive permeant.