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Shear Alignment of Bola-Amphiphilic Arginine-Coated Peptide Nanotubes.

Published version
Peer-reviewed

Type

Article

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Authors

Hamley, Ian W 
Burholt, Samuel 
Hutchinson, Jessica 
Castelletto, Valeria 
da Silva, Emerson Rodrigo 

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.

Description

Keywords

Arginine, Humans, Micelles, Nanotubes, Peptide, Polyethylene Glycols, Rheology, Scattering, Small Angle, Shear Strength, X-Ray Diffraction

Journal Title

Biomacromolecules

Conference Name

Journal ISSN

1525-7797
1526-4602

Volume Title

18

Publisher

American Chemical Society (ACS)

Rights

Publisher's own licence