Electrochemical characteristics of a carbon-based thick-film L-lactate biosensor usign L-lactate dehydrogenase
Hyun C. Yoon, Hak-Sung Kim
Carbon-based thick-film electrodes employing nicotineamide adenine dinucleotide(NAD+)-dependent dehydrogenase were constructed by screen printing. Cyclic voltametric and amperometric investigations of the thick-film electrode showed siginificantly different electrocatalytic properties toward NADH compared to conventional polished electrodes. Electrochemical oxidation of NADH was attained at the low potential of +350mV vs. Ag/AgCl at the thick-film carbon electrode, and can be attributed to increased electrocatalytic sites due to the rough and jagged electrode surface and the formation of a microelectrode array-like structure at the electrode surface. Based on the observations, a thick-film lactate biosensor using L-lactate dehydrogenase was developed. Analytical performance of the resulting lactate biosensor was evaluated in terms of sensitivity and stability.