The interfacial structure and Young's modulus of peptide films having switchable mechanical properties

Middelberg, Anton P. J., He, Lizhong, Dexter, Annette F., Shen, H.-H., Holt, S. A. and Thomas, R. K. (2008) The interfacial structure and Young's modulus of peptide films having switchable mechanical properties. Journal of The Royal Society Interface, 5 18: 47-54. doi:10.1098/rsif.2007.1063

Author Middelberg, Anton P. J.
He, Lizhong
Dexter, Annette F.
Shen, H.-H.
Holt, S. A.
Thomas, R. K.
Title The interfacial structure and Young's modulus of peptide films having switchable mechanical properties
Journal name Journal of The Royal Society Interface   Check publisher's open access policy
ISSN 1742-5689
Publication date 2008-01-06
Year available 2007
Sub-type Article (original research)
DOI 10.1098/rsif.2007.1063
Open Access Status DOI
Volume 5
Issue 18
Start page 47
End page 54
Total pages 8
Place of publication London, England
Publisher Royal Society Publishing
Language eng
Subject C1
0904 Chemical Engineering
970103 Expanding Knowledge in the Chemical Sciences
100799 Nanotechnology not elsewhere classified
100302 Bioprocessing, Bioproduction and Bioproducts
860899 Human Pharmaceutical Products not elsewhere classified
100703 Nanobiotechnology
0303 Macromolecular and Materials Chemistry
030403 Characterisation of Biological Macromolecules
Abstract We report the structure and Young's modulus of switchable films formed by peptide self-assembly at the air–water interface. Peptide surfactant AM1 forms an interfacial film that can be switched, reversibly, from a high- to low-elasticity state, with rapid loss of emulsion and foam stability. Using neutron reflectometry, we find that the AM1 film comprises a thin (approx. 15 Å) layer of ordered peptide in both states, confirming that it is possible to drastically alter the mechanical properties of an interfacial ensemble without significantly altering its concentration or macromolecular organization. We also report the first experimentally determined Young's modulus of a peptide film self-assembled at the air–water interface (E=80 MPa for AM1, switching to E<20 MPa). These findings suggest a fundamental link between E and the macroscopic stability of peptide-containing foam. Finally, we report studies of a designed peptide surfactant, Lac21E, which we find forms a stronger switchable film than AM1 (E=335 MPa switching to E<4 MPa). In contrast to AM1, Lac21E switching is caused by peptide dissociation from the interface (i.e. by self-disassembly). This research confirms that small changes in molecular design can lead to similar macroscopic behaviour via surprisingly different mechanisms.
Keyword Film
Neutron reflectometry
Young's modulus
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
Australian Institute for Bioengineering and Nanotechnology Publications
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Citation counts: TR Web of Science Citation Count  Cited 34 times in Thomson Reuters Web of Science Article | Citations
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Created: Tue, 24 Mar 2009, 23:32:19 EST by Mrs Jennifer Brown on behalf of Aust Institute for Bioengineering & Nanotechnology