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Polymers and Self Assembly: From Biology to Nanomaterials
Wednesday Speaker Abstracts
Designer Peptides Self-Assemble on Graphene to Create Remarkably Stable, Precisely
Organized Substrates
Gina-Mirela Mustata
1,6
, Meni Wanunu
1,2
, Gevorg Gregoryan
3,4
, Jian Zhang
3
, William
DeGrado
5
.
6
Simmons College, Boston, MA, USA.
1
Northeastern University, Boston, MA, USA,
3
Dartmouth
College, Hanover, NH, USA,
2
Northeastern University, Boston, MA, USA,
4
Dartmouth College,
Hanover, NH, USA,
5
University of California, San Francisco, San Francisco, CA, USA,
We present a study of designed self-assembly of 2D peptide monolayer crystals on the surface of
graphene and graphitic interfaces and their properties in various biologically significant
conditions. Atomic force microscopy imaging of dried peptides adsorbed on graphitic surfaces
reveals an amorphous monolayer structure that contains voids due to drying. After rehydration,
the peptide monolayer reorganizes into highly ordered domains comprised by parallel arranged
peptides that are oriented on the graphitic structure with C3 symmetry, in close agreement with
computational predictions. The monolayers are remarkably stable in a wide range of pH, ionic
strengths, urea concentrations, and temperatures. Importantly, we find that alternating peptides
that do not contain aromatic residues organize similarly, and conclude that aromatic residues are
not essential for this organization. The monolayers are highly stable to proteolytic digestion
when full coverage is acquired, while voids in the layer become seeds to slow degradation from
the void inwards. A striking quality of these substrates is the preference to bind double stranded
DNA imposing a preferred alignment to match their own molecular arrangement on the graphene
surface.
This system of designed peptide-coated graphene surfaces, with its stability over a wide range of
situations, presents new opportunities for the design of structures and systems that are significant
in the study of various biological entities and processes, such as specific binding or designed
catalysis.