Application of a large assembly of microelectrodes to the study of cytochrome-c and other redox proteins

A novel microelectrode assembly containing more than 1000 carbon microdisks has been used to study the interfacial electron transfer kinetics of cytochrome c and several other redox proteins. It is demonstrated that near-steady-state current-voltage curves can be obtained without solution stirring, and without significant mains interference or capacitive charging currents. In addition, it is demonstrated that concentrations of redox proteins as low as 1 mu M can be detected in solution. Finally, it is shown that the surfaces of carbon microdisk assemblies can be successfully coated with thin films of poly(ester sulfonic acid), which allows reactants to be studied in a membrane-like environment.