Biophysical Society Thematic Meeting - October 25-30, 2015

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.

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