Self-assembly of hydrophobin protein rodlets studied with atomic force spectroscopy in dynamic mode

S. Houmadi, Raul D. Rodriguez, S. Longobardi, P. Giardina, M. C. Faureí, M. Giocondo, E. Lacaze

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Abstract

We have investigated the self-assembling properties of the class I hydrophobin Vmh2 isolated from the fungus Pleurotus ostreatus. Five different hydrophobin self assembled samples including monolayers, bilayers, and rodlets have been prepared by Langmuir technique and studied at the nanoscale. Local wettability and visco-elasticity of the different hydrophobins samples were obtained from atomic force spectroscopy experiments in dynamic mode performed at different, controlled relative humidity (RH) values. It was found that hydrophobins assembled either in rodlets or in bilayer films, display similar hydropathicity and viscoelasticity in contrast to the case of monolayers, whose hydropathicity and viscoelasticity depend on the adopted preparation method (Langmuir-Blodgett or Langmuir-Schaeffer). The comparison with monolayers properties evidences a rearrangement of the bilayers adsorbed onto solid substrates. It is shown that this rearrangement leads to the formation of a stable hydrophobic film, and that the rodlets structure consists in fragments of restructured proteins bilayers. Our results support the hypothesis that the observed variations in the viscoelastic properties could be ascribed to the localization of the large flexible loop, typical of Class I hydrophobins which appears free at the air interface for LB monolayers but not for the other samples. These findings should now serve future developments and applications of hydrophobin films beyond the archetypal monolayer.

Original languageEnglish
Pages (from-to)2551-2557
Number of pages7
JournalLangmuir
Volume28
Issue number5
DOIs
Publication statusPublished - 7 Feb 2012

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ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

Cite this

Houmadi, S., Rodriguez, R. D., Longobardi, S., Giardina, P., Faureí, M. C., Giocondo, M., & Lacaze, E. (2012). Self-assembly of hydrophobin protein rodlets studied with atomic force spectroscopy in dynamic mode. Langmuir, 28(5), 2551-2557. https://doi.org/10.1021/la2028093