Amplification of Amperometric Biosensor Responses by Electrochemical Substrate Recycling. 3. Theoretical and Experimental Study of the Phenol−Polyphenol Oxidase System Immobilized in Laponite Hydrogels and Layer-by-Layer Self-Assembled Structures

• Published in: Analytical chemistry (Washington) Vol. 73; no. 14; pp. 3206 - 3218
• Main Authors: Coche-Guerente, L, Labbé, P, Mengeaud, Virginie
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15.07.2001
• Subjects: Amperometric sensors; Biological and medical sciences; Biosensing Techniques - methods; Biosensors; Biotechnology; Catechol Oxidase - chemistry; Catechol Oxidase - metabolism; Electrochemistry; Electrochemistry - methods; Enzyme immobilization; Enzymes, Immobilized - chemistry; Enzymes, Immobilized - metabolism; Fundamental and applied biological sciences. Psychology; Hydrogels; Hydrogels - chemistry; Kinetics; Methods. Procedures. Technologies; Monolayers; Oxidation; Oxidation-Reduction; Phenol - chemistry; Phenol - metabolism; Phenols; Reduction; Self assembly; Various methods and equipments; Performance evaluation; Electrode adsorption; Laponite; Enzyme; Rotating disk electrode; Theoretical study; Catechol oxidase; Enzyme electrode; Electrochemical detector; Ion selective electrode; Matrix isolation; Polyelectrolyte; Kinetic model; Enzymatic activity; Biosensor; Phenols; Benzenic compound; Oxidoreductases; Kinetic parameter; Liquid permeability; Immobilized enzyme
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac001534l

The amperometric response toward phenol of PPO-based rotating disk bioelectrodes is analyzed on the basis of a kinetic model taking into account internal and external mass transport effects and a CEC‘ electroenzymatic mechanism. Monophenolase activity of PPO catalyses the oxidation of phenol to o-quinone (step C). o-Quinone can then enter an amplification recycling process involving electrochemical reduction (step E) and enzymatic reoxidation (step C‘:  catecholase activity). The rate-limiting steps such as monophenolase activity, catecholase recycling, permeability of the membrane, and activity and accessibility of the catalytic enzyme sites are theoretically considered and experimentally demonstrated for different electrode configurations including PPO immobilized in Laponite hydrogels and layer-by-layer self-assembled multilayers of PPO and poly(diallyldimethylammonium).