Self-assembly of stimuli-responsive peptide films at fluid-fluid interfaces

ORGN 325

Annette F. Dexter, a.dexter@uq.edu.au and Anton PJ. Middelberg, a.middelberg@uq.edu.au. Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia QLD 4072, Australia
We have developed a novel peptide capable of forming a stimuli-responsive film at a fluid-fluid interfaces. At neutral pH the 21-residue helical peptide, AM1, self-assembles as a monolayer at an air-water or oil-water interface. Inclusion of divalent zinc in the bulk solution leads to cross-linking of the peptide film via metal binding to histidine residues. The resulting mechanically strong film can inhibit coalescence in foams or emulsions containing the peptide, as shown by the high emulsifying and foaming activity of the peptide in the presence of zinc. Disruption of zinc-peptide binding by the addition of acid or a metal chelating agent to a pre-formed foam or emulsion leads to rapid phase coalescence. The peptide thus allows the preparation of stimuli-responsive foams and emulsions, with potentially broad applications in consumer products, pharmaceutical formulation and biocatalysis.