Nanotechnology brings new possibilities for the development of sensors, biosensors, and novel electrochemical bioassays. Nanoscale materials have been extensively used in a wide variety of configurations — as electrode surfaces to promote electrochemical reaction, as "wires" to enzymes connecting their redox centers to electrode surface, as nanobarcodes for biomolecules, or as tags to amplify the signal of a biorecognition event.  Meer