Fabrication of ultra-thin polypyrrole-glucose oxidase film from supportingelectrolyte-free monomer solution for potentiometric biosensing of glucose

A simple electropolymerisation process is described for the fabrication of an ultra-thin (similar to 55 nm) polypyrrole (PPy)-glucose oxidase (GOD) fi lm in a supporting electrolyte-free monomer solution for potentiometric bio sensing of glucose. The optimum conditions for growing the ultra-thin film include 0.1 M pyrrole, 55-110 U/ml GOD, an applied current density of 0.05 mA/cm(2) and an electrical charge of 25 mC/cm(2). Long-term storage of the biosensor in acetate buffer improved the sensitivity of the biosensor by a factor of approximately two. The biosensor can also be used repeatedly for over 2 months with little or no loss in sensitivity. The interference effec t of ascorbic acid was successfully reduced by inclusion of an outer PPy-Cl layer. (C) 2001 Elsevier Science S.A. All rights reserved.