# Optimization and characterization of a lactate-oxidase electrode

## TL;DR

Researchers improved a lactate sensor electrode by optimizing enzyme and polymer layers, leading to better performance and stability for healthcare and sports applications.

## Contribution

A novel optimization method for lactate oxidase electrode layers using the Box–Behnken design was developed and tested.

## Key findings

- An optimized electrode with four layers of LOx and PEGDGE achieved an oxidation current of 1840 ± 60 μA.
- The electrode showed maximum current at 50 mM lactate concentration and an apparent Kappm of 11.4 mM.
- The electrode demonstrated high stability and robust enzyme binding for repeated use.

## Abstract

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 Kappm 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.

The performance of the lactate oxidase electrode was enhanced by optimizing the loading and layering of lactate oxidase and poly(ethylene glycol) diglycidyl ether on carbon paper.