  We implemented a nanoelectronic interface between graphene field effect
transistors (FETs) and soluble proteins. This enables production of
bioelectronic devices that combine functionalities of the biomolecular and
inorganic components. The method serves to link polyhistidine-tagged proteins
to graphene FETs using the tag itself. Atomic Force Microscopy and Raman
spectroscopy provide structural understanding of the bio/nano hybrid;
current-gate voltage measurements are used to elucidate the electronic
properties. As an example application, we functionalize graphene FETs with
fluorescent proteins to yield hybrids that respond to light at wavelengths
defined by the optical absorption spectrum of the protein
