A Single-Metalloprotein Wet Biotransistor

Andrea Alessandrini1, Stefano Frabboni1,2, and Paolo Facci1

1INFM National Research Center on "nanoStructures and bioSystems at Surfaces" (S3), University of Modena and Reggio Emilia, Via Campi 213A, I-41100 Modena, Italy , and
2Department of Physics, University of Modena and Reggio Emilia, I-41100 Modena, Italy

e-mail: p.facci@unimore.it

URL: http://www.biophysics.unimo.it


Metalloproteins are redox biomolecules naturally shuttling electrons with high efficiency between molecular partners. As such, they are candidates of choice for bioelectronics. In this work we have used bacterial blue-copper protein azurin, hosted in a nanometer gap between two electrically biased gold electrodes, to demonstrate an electrochemically gated single-molecule transistor operating in aqueous environment. Gold-chemisorbed azurin shows a resonant behavior in redox level-assisted tunnelling current upon changing electrode potential and a related variation in tunnelling barrier transparency which can be exploited to switch electron flow through it. These results suggest the wet approach to molecular electronics as a viable method for exploiting electron transfer properties of highly specialized biomolecules.