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

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%.