Optimization and characterization of a lactate-oxidase electrode

Electrochemical lactate sensors, used for analyzing biological fluids such as blood, sweat, and saliva, are gaining significant interest in healthcare and sports fields. A pivotal element that affects these sensors' performance is the lactate oxidase-based electrode. This study focused on enhancing the performance of the lactate oxidase electrode by optimizing the loading and layering of lactate oxidase (LOx) and poly(ethylene glycol) diglycidyl ether (PEGDGE) on carbon paper via the Box-Behnken design. The electrode surface was characterized utilizing FE-SEM, FTIR, and impedance analyses, with performance evaluation conducted via electrochemical and biochemical analyses. The optimized electrode, incorporating four layers of LOx (1.9 U) and PEGDGE (184 μg), generated an oxidation current of 1840 ± 60 μA, displaying high enzyme activity. It exhibited a maximum current at a lactate concentration of 50 mM, an apparent K ^app _m of 11.4 mM, and high stability with robust enzyme binding, thus supporting repeated use across numerous cycles. These results are instrumental in advancing the development of more effective and dependable lactate biosensors.