LOW-COST ENZYME-BASED BIOSENSOR FOR LACTIC ACID AMPEROMETRIC DETECTION Electrical Modeling and Validation for Clinical and Food Processing Applications

In this work we present the preliminary resulting measurements of an enzyme-based biosensor for the amperometric detection of lactic acid (LA). The sensor is based on low-cost gold electrodes on polymeric substrate. The redox catalytic enzyme used for analyte amperometric detection is lactate oxidase (LOx) from Pediococcus sp. This enzyme has been immobilized over electrodes surfaces by direct adsorption methodologies. Analysis of the enzyme-modified electrodes have been carried out by means of Electrochemical Impedance Spectroscopy (EIS) and with the development of an equivalent electrical model, in order to improve the adsorption process. Biosensors performance have been evaluated with Cyclic Voltammetry (CVM) measurements in different lactic acid solutions with concentrations from 1 mu M up to 300 mM. The lactate sensitivity of this disposable biosensor results in about 6.24 mu A mM(-1) cm(-2).