title: Reversible active switching of the mechanical properties of a peptide film at a fluid-fluid interface.
abstract: Designer peptides have recently been developed as building blocks for novel self-assembled materials with stimuli-responsive properties. To date, such materials have been based on self-assembly in bulk aqueous solution or at solid-fluid interfaces. We have designed a 21-residue peptide, AM1, as a stimuli-responsive surfactant that switches molecular architectures at a fluid-fluid interface in response to changes in bulk aqueous solution composition. In the presence of divalent zinc at neutral pH, the peptide forms a mechanically strong 'film state'. In the absence of metal ions or at acid pH, the peptide adsorbs to form a mobile 'detergent state'. The two interfacial states can be actively and reversibly switched. Switching between the two states by a change in pH or the addition of a chelating agent leads to rapid emulsion coalescence or foam collapse. This work introduces a new class of surfactants that offer an environmentally friendly approach to control the stability of interfaces in foams, emulsions and fluid-fluid interfaces more generally.
authors.affiliation: Centre for Biomolecular Engineering, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia Queensland 4072, Australia.
authors.forename: Annette F
authors.initials: AF
authors.lastname: Dexter
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Malcolm
authors.forename: Anton P J
authors.initials: AP
authors.lastname: Middelberg
mesh_terms: D003902:Detergents / Q000737:chemistry; D008422:Materials Testing; D008567:Membranes, Artificial; D010455:Peptides / Q000737:chemistry*; D012996:Solutions / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry
chemical_list: D003902:Detergents; D008567:Membranes, Artificial; D010455:Peptides; D012996:Solutions; D013501:Surface-Active Agents