Amperometric Biosensor Based on Immobilization of OxalateOxidase in a Mucin/Chitosan Matrix

TOMAS E. BENAVIDEZ; RAUL H. CAPRA; CECILIA I. ALVAREZ; ANA M. BARUZZI

ELECTROANALYSIS

Wiley-VCH

Lugar: La Jolla, USA; Año: 2009 vol. 21 p. 837 - 843

1040-0397

An amperometric electrode for oxalate determination immobilizing the oxalate oxidase in a mucin/chitosan (muc/chit) gel with glutaraldehyde as crosslinking agent is presented. The effect of muc/chit weight ratio and volume percent (vol.-%) of glutaraldehyde was studied. A very low dynamic response was observed in the case of 100% chitosan with 5 vol.-% crosslinking agent. The addition of mucin to chitosan for enzyme immobilization resulted in a biosensor with much better performance, concerning to dynamic response, sensitivity, and stability, with 75% of the initial response after two months. The ratio muc/chit 70/30 was considered optimum for the immobilization. A slight crosslinking and the incorporation of mucin largely influences the swelling and diffusion of the analyte; a direct effect of these properties on the calibration slope was found; the hydrophilic environment for the biomolecule also favour the enzymatic activity through a higher enzyme-substrate interaction.