Electrochemical, STM and XPS characterization of FAD-modified gold electrodes

MARÍA ANTONIETA DAZA MILLONE; MARÍA ELENA VELA; MARIANO H. FONTICELLI; GUILLERMO BENÍTEZ; ROBERTO C. SALVAREZZA

Trieste (Italia)

Workshop; Advanced Workshop on Recent Developments; 2007

Flavins are responsible for NAD+/NADH conversion but without a protein enviroment they show poor catalytic activity. The redox center of the protein is embedded deep in the tertiary structure of the polypeptide thus insulating the redox active site from the bulk solution. Self-assembled monolayers (SAMs) of alkanethiols provide a hydrophobic enviroment and an electron transfer model for biological membranes. So, it is interesting to investigate the properties of electrodes modified with SAMs and adsorbed flavins as possible tools for bioanalytical purposes. The NAD+ electroreduction process at conventional electrodes is commonly hindered by a large overvoltage and surface fouling effects (due to the formation of NAD2 dimer). Reduce this overpotential and minimize surface passivation effects is of considerable biotechnological interest. C12 protects gold and prevents the fouling effects and FAD immobilized on it enables NAD+/NADH reaction from NAD+ in solution.