Design an Amperometric Biosensor for the Detection of Lactate

Abstract

In this study, we present the design of a new electrode material, as a L-lactate selective electrochemical sensor. We identified the conditions under which the mediator DHB-Nafion provides the best reversibility and robustness. We also found that by using a Nafion overlayer 50% of modified material is preserved. With these conditions the electrochemical detection of NADH is carried out. By adding to the molecular electrode's material L-LDH enzyme, the detection is accomplished at different concentrations of L-lactate. Finally we performed the determination of L-lactate under hydrodynamic regime. The working potential under hydrodynamic regime is 0.56 V vs. Ag/AgCl (pH 7.4) in 50 mM phosphate buffer with 50 mM KCl as supporting electrolyte. The results from the calibration curve obtained by linear regression was 0.9826 at concentrations from 0.0 to 0.6 mM of L-lactate, and 0.9738 at concentrations from 0.7 to 0.11 mM of L-lactate.