title: Shear Alignment of Bola-Amphiphilic Arginine-Coated Peptide Nanotubes.
abstract: The bola-amphiphilic arginine-capped peptide RFL4RF self-assembles into nanotubes in aqueous solution. The nanostructure and rheology are probed by in situ simultaneous rheology/small-angle scattering experiments including rheo-SAXS, rheo-SANS, and rheo-GISANS (SAXS: small-angle X-ray scattering, SANS: small-angle neutron scattering, GISANS: grazing incidence small-angle neutron scattering). Nematic alignment of peptide nanotubes under shear is observed at sufficiently high shear rates under steady shear in either Couette or cone-and-plate geometry. The extent of alignment increases with shear rate. A shear plateau is observed in a flow curve measured in the Couette geometry, indicating the presence of shear banding above the shear rate at which significant orientation is observed (0.1-1 s-1). The orientation under shear is transient and is lost as soon as shear is stopped. GISANS shows that alignment at the surface of a cone-and-plate cell develops at sufficiently high shear rates, very similar to that observed in the bulk using the Couette geometry. A small isotope effect (comparing H2O/D2O solvents) is noted in the CD spectra indicating increased interpeptide hydrogen bonding in D2O, although this does not influence nanotube self-assembly. These results provide new insights into the controlled alignment of peptide nanotubes for future applications.
authors.affiliation: Department of Chemistry, University of Reading , Whiteknights, Reading, RG6 6AD, United Kingdom.
authors.forename: Ian W
authors.identifier: 0000-0002-4549-0926
authors.initials: IW
authors.lastname: Hamley
authors.affiliation: Department of Chemistry, University of Reading , Whiteknights, Reading, RG6 6AD, United Kingdom.
authors.forename: Samuel
authors.initials: S
authors.lastname: Burholt
authors.affiliation: Department of Chemistry, University of Reading , Whiteknights, Reading, RG6 6AD, United Kingdom.
authors.forename: Jessica
authors.initials: J
authors.lastname: Hutchinson
authors.affiliation: Department of Chemistry, University of Reading , Whiteknights, Reading, RG6 6AD, United Kingdom.
authors.forename: Valeria
authors.initials: V
authors.lastname: Castelletto
authors.affiliation: Instituto de Física, Universidade Federal de Alagoas , Maceió-Alabama 57072-900, Brazil.
authors.forename: Emerson Rodrigo
authors.initials: ER
authors.lastname: da Silva
authors.affiliation: Centro de Ciências Naturais e Humanas, Universidade Federal do ABC , Santo André 09210-580, Brazil.
authors.forename: Wendel
authors.identifier: 0000-0002-8394-2751
authors.initials: W
authors.lastname: Alves
authors.affiliation: Institut Max von Laue - Paul Langevin , CS 20156; 71, Avenue des Martyrs F-38042 Grenoble Cedex 9, France.
authors.forename: Philipp
authors.initials: P
authors.lastname: Gutfreund
authors.affiliation: Institut Max von Laue - Paul Langevin , CS 20156; 71, Avenue des Martyrs F-38042 Grenoble Cedex 9, France.
authors.forename: Lionel
authors.initials: L
authors.lastname: Porcar
authors.affiliation: ESRF-The European Synchrotron , 38043 Grenoble Cedex 9, France.
authors.forename: Rajeev
authors.initials: R
authors.lastname: Dattani
authors.affiliation: ESRF-The European Synchrotron , 38043 Grenoble Cedex 9, France.
authors.forename: Daniel
authors.initials: D
authors.lastname: Hermida-Merino
authors.affiliation: ESRF-The European Synchrotron , 38043 Grenoble Cedex 9, France.
authors.forename: Gemma
authors.initials: G
authors.lastname: Newby
authors.affiliation: Department of Applied Physics, Aalto University School of Science , Aalto FI-00076, Finland.
authors.forename: Mehedi
authors.initials: M
authors.lastname: Reza
authors.affiliation: Department of Applied Physics, Aalto University School of Science , Aalto FI-00076, Finland.
authors.forename: Janne
authors.initials: J
authors.lastname: Ruokolainen
authors.affiliation: Department of Chemical Engineering & Biotechnology, University of Cambridge , Pembroke Street, Cambridge, CB2 3RA, United Kingdom.
authors.forename: Joanna
authors.initials: J
authors.lastname: Stasiak
mesh_terms: D001120:Arginine / Q000737:chemistry*; D006801:Humans; D008823:Micelles; D045333:Nanotubes, Peptide / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D012212:Rheology; D053838:Scattering, Small Angle; D033081:Shear Strength; D014961:X-Ray Diffraction
chemical_list: D008823:Micelles; D045333:Nanotubes, Peptide; D011092:Polyethylene Glycols; D001120:Arginine