Development of a new method of improving the oxidase‐based biosensors′ analytical characteristics by adding catalase as an auxiliary enzyme

Abstract This research investigated the possibility of using the method of adding an additional enzyme to a monoenzyme oxidase‐based biosensor to improve the biosensor's analytical characteristics. Namely, the catalase (CAT) was used to better saturate the biomembrane with oxygen for the best glucose oxidase (GOx) performance. For this purpose, two different biosensors were created – based on one enzyme (GOx) and two (GOx and CAT). To create a bioselective membrane, the method of covalent binding in vapors of glutaraldehyde was used. The method of coimmobilization of catalase (CAT) and glucose oxidase (GOx) enzymes, as well as the concentration of enzymes in the mixture, was chosen in the work. The stability of the biosensor functioning, i. e. the repeatability during measurements and the reproducibility of the biosensors’ preparation, were investigated. Analytical characteristics of the proposed biosensor were studied in comparison with a monoenzyme biosensor based on glucose oxidase only. It was shown that the addition of catalase as an auxiliary enzyme significantly improves the analytical characteristics of the biosensor, in particular, the sensitivity, the repeatability of the measurement results, and the limits of the linear and dynamic ranges of operation. The developed method can be successfully used to optimize conductometric enzyme biosensors based on oxidases.