Electrochemical Kinetic Characterization of Redox Mediated Glucose Oxidase Reactions: A Simplified Approach

Abstract

One of the main drawbacks affecting first-generation electrochemical biosensors in the analysis of real matrices is the interference of electroactive species present in the sample under investigation. Several approaches have been attempted to overcome this problem in the past ten years but the best results were achieved by using mediated based electrochemical biosensors. Despite this, the kinetic of the redox mediators-enzymatic proteins interaction has not been studied deeply enough. In this work we have developed a theoretical-methodological approach for the characterization of the kinetic of interaction between redox enzymes and substrates and/or redox mediators. Particularly, the interaction of glucose oxidase (GOx) with several commercially available redox mediators has been studied by means of amperometry and cyclic voltammetry. The main kinetic parameters for different mediators were exploited and discussed with the aim of finding the best mediator for a glucose biosensor to be used on real samples.

Polyazetidine-based immobilization of redox proteins for electron-transfer-based biosensors

“…The use of a non-linear fitting (SigmaPlot Kinetic Module, see http://www.sigmaplot.com) to these data allowed the main kinetic parameters to be computed; in particular, K app MS = 5.4 mM; I max = 7.05 A (correlation coefficient r 2 = 0.9960). The higher value of the immobilized GOx Michaelis constant than that obtained with the same enzyme free in solution (Delle Noci et al, 2008) confirms that the affinity towards a substrate of an enzyme is lowered, once the enzyme has been immobilized, as previously reported (Hong et al, 2007).…”

“…To this end, glucose oxidase (GOx) was immobilized in the PAP layer on a GCE; the response of the resulting biosensor to increasing concentration of glucose (as substrate) was studied in 1 mM FCA solution (as mediator). This concentration value fits the requirement discussed elsewhere, namely that above a certain concentration value of reduced mediator, the catalytic current attains a limiting value, thus simplifying kinetic treatment and enabling an easy calculation of the parameters involved (Delle Noci et al, 2008).…”

Electrochemical Characterization of Graphene and MWCNT Screen-Printed Electrodes Modified with AuNPs for Laccase Biosensor Development

“…Steady-state currents were always observed and kinetic evaluations were solved according to a method based on chronoamperometric measurements recently developed in our laboratories [ 36 ].…”

Bioelectrochemical Characterization of Horseradish and Soybean Peroxidases

“…The considered peroxidases (HRP and SBP) have been characterized both from a kinetic and a bioelectrochemical point of view; as far as the kinetic characterization is concerned, the experiments were carried out under the specific conditions for the determination of the Michaelis constants towards both substrate (K MS ) and mediators (K MM ) as already reported in our previous paper [21]. The treatment is originally given by Albery et al [26] and the model has been reviewed by Bartlett and Pratt [27]; it represents one of the most generally used theoretical approaches to analyze experimental voltammetric data for the homogeneous system in order to extract the relevant kinetic constants for the considered reactions.…”

“…As described in previous paper [21], the current intensity can be obtained by means of the following general equation:…”