title: Charge transport and intrinsic fluorescence in amyloid-like fibrils.
abstract: The self-assembly of polypeptides into stable, conductive, and intrinsically fluorescent biomolecular nanowires is reported. We have studied the morphology and electrical conduction of fibrils made of an elastin-related polypeptide, poly(ValGlyGlyLeuGly). These amyloid-like nanofibrils, with a diameter ranging from 20 to 250 nm, result from self-assembly in aqueous solution at neutral pH. Their morphological properties and conductivity have been investigated by atomic force microscopy, scanning tunneling microscopy, and two-terminal transport experiments at the micro- and nanoscales. We demonstrate that the nanofibrils can sustain significant electrical conduction in the solid state at ambient conditions and have remarkable stability. We also show intrinsic blue-green fluorescence of the nanofibrils by confocal microscopy analyses. These results indicate that direct (label-free) excitation can be used to investigate the aggregation state or the polymorphism of amyloid-like fibrils (and possibly of other proteinaceous material) and open up interesting perspectives for the use of peptide-based nanowire structures, with tunable physical and chemical properties, for a wide range of nanobiotechnological and bioelectronic applications.
authors.affiliation: National Nanotechnology Laboratory, Istituto Nazionale per la Fisica della Materia-Consiglio Nazionale della Ricerche, University of Salento, Lecce, Italy. loretta.delmercato@unile.it
authors.forename: Loretta Laureana
authors.initials: LL
authors.lastname: Del Mercato
authors.forename: Pier Paolo
authors.initials: PP
authors.lastname: Pompa
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Maruccio
authors.forename: Antonio
authors.initials: A
authors.lastname: Della Torre
authors.forename: Stefania
authors.initials: S
authors.lastname: Sabella
authors.forename: Antonio Mario
authors.initials: AM
authors.lastname: Tamburro
authors.forename: Roberto
authors.initials: R
authors.lastname: Cingolani
authors.forename: Ross
authors.initials: R
authors.lastname: Rinaldi
mesh_terms: D000595:Amino Acid Sequence; D000682:Amyloid / Q000378:metabolism*; D008853:Microscopy / Q000379:methods; D053770:Nanowires; D009842:Oligopeptides / Q000737:chemistry / Q000378:metabolism; D013050:Spectrometry, Fluorescence
chemical_list: D000682:Amyloid; D009842:Oligopeptides