Structuring with peptides
Advanced Materials is a regular column featuring novel materials of
interest to the oils and fats community.
Among the biomolecules, proteins and peptides (short proteins) are surely the masters of self-assembly. While the DNA double helix is iconic; and RNA the poster-child for pattern recognition;
the sheer number and diversity of protein and peptide assemblies is unprecedented. Little wonder
then that materials scientists, have sought to capture and direct the self-assembly of peptides to
create complex materials from simple building blocks.
In 2003, Ehud Gazit, a professor of molecular microbiology and biotechnology at Tel Aviv University in Israel, discovered the self-assembly of di-phenylalanine (FF), and observed
that short aromatic peptides (pentapeptide and shorter) could
form well-ordered amyloid fibrils—research that has led to
new insights into diseases such as Alzheimer’s. Gazit has proposed that these structures be used as scaffolds for nanoelec-tronics applications and sensors.
Sequences inspired by naturally assembling systems, such
as the prion proteins, have been extensively studied for biomedical applications. Researchers such as Shuguang Zhang,
a professor in the Center for Biomedical Engineering at MIT
in Cambridge, Massachusetts, USA, and Darrin Pochan, a professor of Materials Science & Engineering at the University
of Delaware, USA, have identified sequences of amino acids
which show potential as supports for biological tissue repair.
Pochan’s proposed sequences of 20 amino acid peptides containing valine and lysine repeats self-assemble to form a gel
which can shear thin as it is injected and then quickly restructure once in the body.
In 2006, Annette F. Dexter and Anton Middelberg created
a startup company, Pepfactants Pty Ltd, at the University of
Queensland in Australia, which promoted a 21-residue peptide as a stimuli-responsive surfactant that switches molecular
architectures at a fluid–fluid interface in response to changes
in bulk aqueous solution composition.
“This is indeed a very exciting field. Peptide assemblies
may provide a very interesting use in industry,” says Gazit. “It
is clear that very short peptides—as short as dipeptides—can
form functional assemblies. The physical properties are quite
astonishing. The building blocks are simple, inexpensive, envi-ronmentally-friendly. Nature has used self-assembly to form
various functional structures while avoiding the use of heavy
and toxic metals as with inorganic materials.”