Charge transport and intrinsic fluorescence in amyloid-like fibrils.
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.
Del Mercato
Loretta Laureana
LL
National Nanotechnology Laboratory, Istituto Nazionale per la Fisica della Materia-Consiglio Nazionale della Ricerche, University of Salento, Lecce, Italy. loretta.delmercato@unile.it
Pompa
Pier Paolo
PP
Maruccio
Giuseppe
G
Della Torre
Antonio
A
Sabella
Stefania
S
Tamburro
Antonio Mario
AM
Cingolani
Roberto
R
Rinaldi
Ross
R
D000595:Amino Acid Sequence; D000682:Amyloid / Q000378:metabolism*; D008853:Microscopy / Q000379:methods; D053770:Nanowires; D009842:Oligopeptides / Q000737:chemistry / Q000378:metabolism; D013050:Spectrometry, Fluorescence
D000682:Amyloid; D009842:Oligopeptides