Influence of calcium on glucose biosensor response and on hydrogen peroxide detection

Nathalie Labat-Allietta,Daniel R Thévenot

doi:10.1016/s0956-5663(97)00084-5

Abstract

Of small species capable of reaching a platinum working electrode from biological samples, calcium cations have been found to inhibit significantly glucose biosensor responses. The sensitivities to glucose of sensors immersed in carbonate buffer saline solutions decreased when 0·5 mM calcium chloride was added. The degree of inhibition was proportional to the glucose response in the absence of calcium (0–17% of the normalized current). Likewise, sensor sensitivities to hydrogen peroxide decreased, in the 5–90% range, in the presence of 0·5 mM calcium. Bare PtIr wires show a reversible inhibition of hydrogen peroxide sensitivity. This reversible inhibition is directly related to the decrease of hydrogen peroxide oxidation rate at the platinum anode: this has been evidenced, using rotating disk electrodes, by plotting Koutecky-Levich plots. Such inhibition has been found both for free and chelated calcium cations at levels below 1 mM. Several hypotheses for possible reactions between platinum, hydrogen peroxide and calcium are discussed.

Highlights

Among the numerous applications of biosensors, the development of an implantable sensor for glucose has been one of the most challenging and most studied problems (Wilson et al, 1991)
Taking into account the very different PU permeabilities to glucose and hydrogen peroxide, it seems that calcium is interfering with the anodic oxidation of hydrogen peroxide
Results obtained on bare Pt-Ir wires indicate that the interaction with calcium is reversible and presents an amplitude within the range observed on glucose sensors

Summary

Introduction

Among the numerous applications of biosensors, the development of an implantable sensor for glucose has been one of the most challenging and most studied problems (Wilson et al, 1991). 2-4 seem to indicate that the calcium inhibition mechanism should be common both to glucose and to hydrogen peroxide responses and Relative Sensitivity (%) 1001

Results

Conclusion