Comparison of the performances of two bi-enzymatic sensors for the detection of D-lactate

Abstract

The performances of two bi-enzymatic amperometric biosensors for the detection of d-lactate were compared. In both sensors, d-lactate dehydrogenase was coupled either with diaphorase (which accepts hexacyanoferrate III as an electronic relay) or NADH oxidase (which accepts O2 as an electronic relay). The enzymes were confined in the reaction chamber defined by the surface of a flat platinum electrode and a dialysis membrane. The electrochemical detection was based on the oxidation at a platinum electrode of the final enzyme step reaction products (hexacyanoferrate II or hydrogen peroxide). The potential difference applied between two platinum electrodes was respectively 100 mV for hexacyanoferrate II and 550 mV for hydrogen peroxide detection. The performances of the two biosensors were compared in terms of sensitivity, range of linearity of the response, storage and operational stability.