Polyelectrolyte stabilized oxidase based biosensors: effect of diethylaminoethyl-dextran on the stabilization of glucose and lactate oxidases into porous conductive carbon

• Published in: Analytica chimica acta 2000-01, Vol.404 (1), p.67-73
• Main Authors: Gavalas, Vasilis G., Chaniotakis, Nikolas A.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Biosensor; Biosensors; Biotechnology; Fundamental and applied biological sciences. Psychology; Methods. Procedures. Technologies; Operational stability; Polyelectrolyte; Porous carbon electrode; Various methods and equipments
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/S0003-2670(99)00688-1

The lifetime and the reproducibility of novel enzyme stabilizing techniques based on polyelectrolyte agents such as diethylamimoethyl-dextran have been studied. Glucose oxidase and lactate oxidase, used as the model enzymes, are stabilized with the cationic polyelectrolyte, and the resulting enzyme–polyelectrolyte complexes are physically adsorbed into a highly porous and conductive carbon electrode for the construction of the biosensors. The amounts of diethylaminoethyl-dextran and enzyme are optimized with respect to sensor’s sensitivity and stability. Optimum results were obtained using soaking solutions of 2500 U/ml GOx and 1.0 w/v deae-dextran. Additionally, experiments with lactate oxidase sensors constructed using 200 U/ml LOx and 0.5% w/v deae-dextran solution showed improved operational, and storage stability. The sensor-to-sensor reproducibility was good, the relative standard deviation being less than 5.0%.