Authors: Rasa Pauliukaite Mariana Emilia Ghica Madalina Barsan Christopher M A Brett
Publish Date: 2007/03/16
Volume: 11, Issue: 7, Pages: 899-908
Abstract
The polymer redox mediator polyneutral red PNR has been synthesised and characterised electrochemically to investigate the best electropolymerisation and mediation conditions for application in enzyme biosensors and to clarify the mechanism of action Neutral red was electropolymerised by potential cycling on carbon film electrode substrates by allowing the monomer to be oxidised during the full 20 cycles of polymerisation or reducing the positive limit of the potential window after the first 2 cycles to impede monomer oxidation with a view to obtaining longer polymer chains and a lesser degree of branching Comparison was made with glassy carbon substrates The PNR films on carbon film electrodes were characterised using cyclic voltammetry and electrochemical impedance spectroscopy as well as in glucose biosensors prepared with PNR Glucose oxidase enzyme was immobilised by encapsulation in silica solgel and compared with that obtained by crosslinking with glutaraldehyde The biosensors were evaluated by chronoamperometry in 01 M phosphate buffer saline solution pH 70 and showed evidence of electron transfer between the enzyme cofactor flavin adenine dinucleotide and PNR dissolved in the enzyme layer competing with PNRmediated electrochemical degradation of H2O2 formed during the enzymatic processFinancial support from Fundação para Ciência e Tecnologia FCT Portugal RP thanks FCT for a Postdoctoral fellowship SFRH/BPD/14518/2003 and MEG for a PhD grant SFRH/BD/14014/2003 Prof HD Liess is thanked for the gift of the electrical resistors
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