A protein field-effect transistor (Pro-FET) based on the blue-copper protein azurins (see Figure) and operating at room temperature and ambient pressure is demonstrated. The transfer... Show moreA protein field-effect transistor (Pro-FET) based on the blue-copper protein azurins (see Figure) and operating at room temperature and ambient pressure is demonstrated. The transfer characteristics of the Pro-FET exhibit a pronounced resonance due to the switch from behaving as a n-metal oxide semiconductor FET (n-MOSFET) to a p-MOSFET. Carrier transport through the device is explained in terms of an equilibrium between the two possible oxidation states of the redox site (Cu1+ and Cu2+). Show less
We have studied the morphological, conformational, and electron-transfer (ET) function of the metalloprotein azurin in the solid state, by a combination of physical investigation methods, namely... Show moreWe have studied the morphological, conformational, and electron-transfer (ET) function of the metalloprotein azurin in the solid state, by a combination of physical investigation methods, namely atomic force microscopy, intrinsic fluorescence spectroscopy, and scanning tunneling microscopy. We demonstrate that a “solid state protein film” maintains its nativelike conformation and ET function, even after removal of the aqueous solvent. Show less
The assessment of the folding and of the structural stability of a protein in air, upon immobilization in the solid state, represents a critical point from both a fundamental point of view and for... Show moreThe assessment of the folding and of the structural stability of a protein in air, upon immobilization in the solid state, represents a critical point from both a fundamental point of view and for the development of solid state nanobioelectronics. The recent demonstrations by Rinaldi [R. Rinaldi , Adv. Mater. 14, 1453 (2002); Appl. Phys. Lett. 82, 472 (2003); Ann. (N.Y.) Acad. Sci. 1006, 187 (2003)] of protein-based solid state devices and transistors working in air have raised an intriguing question about the behavior of a biomolecule under nonphysiological conditions. The operation principle of the realized devices is based on the physiological electron transfer function of the metalloprotein azurin. This means that azurin should retain its shape and functionality also in the solid state when utilized in air and at room temperature. In this Brief Report, we prove this claim by analyzing the conformational state of the azurin monolayers developed for such devices by means of intrinsic fluorescence spectroscopy. We show that the immobilization of azurins in the solid state under nonliquid conditions, by means of a specific chemisorption process, does not necessarily lead to protein denaturation. This result is of great importance because it opens up interesting perspectives for the development of solid state hybrid nanodevices for electronic applications requiring nonliquid environments. Show less
We have studied the morphological, conformational, and electron-transfer (ET) function of the metalloprotein azurin in the solid state, by a combination of physical investigation methods, namely... Show moreWe have studied the morphological, conformational, and electron-transfer (ET) function of the metalloprotein azurin in the solid state, by a combination of physical investigation methods, namely atomic force microscopy, intrinsic fluorescence spectroscopy, and scanning tunneling microscopy. We demonstrate that a “solid state protein film” maintains its nativelike conformation and ET function, even after removal of the aqueous solvent. Show less
We show that the electron-transfer protein azurin can be used to fabricate biomolecular rectifiers exploiting its native redox properties, chemisorption capability and electrostatic features. The... Show moreWe show that the electron-transfer protein azurin can be used to fabricate biomolecular rectifiers exploiting its native redox properties, chemisorption capability and electrostatic features. The devices consist of a protein layer interconnecting nanoscale electrodes fabricated by electron beam lithography. They exhibit a rectification ratio as large as 500 at 10 V, and operate at room temperature and in air. (C) 2003 American Institute of Physics. Show less
