AMPEROMETRIC BIOSENSORS BASED ON ELECTROCATALYTIC REGENERATION OF NAD+ AT REDOX POLYMER-MODIFIED ELECTRODES

Amperometric biosensors based on redox polymer-mediated electron transfer from NADH to carbon paste electrodes, regenerating the NAD+ needed for the dehydrogenase-catalysed reaction, are described. These sensors, operating around 0 mV vs SCE, can drive an unfavourable equilibrium of a dehydrogenase-catalysed reaction to the product side, and are reagentless in that NAD+ need not be added to the analyte solution. By covering the sensor with an additional polymer, protection of the electrode surface, inclusion of water soluble components, exclusion of interferents and a diffusion controlled linear response current can be obtained.