Graphene Symmetry Amplified by Designed Peptide Self-Assembly

Area of Science:

• Materials Science
• Nanotechnology
• Biophysics

Background:

• Controlling peptide self-assembly at the nanoscale is crucial for developing novel functional materials.
• Graphene and graphite offer unique atomically flat surfaces with inherent symmetry that can template molecular organization.

Purpose of the Study:

• To develop a strategy for designing peptide self-assembly into ordered two-dimensional (2D) monolayer crystals on graphene and graphite surfaces.
• To investigate how the atomic structure of graphene influences the arrangement and orientation of self-assembled peptide structures.
• To explore the potential of these peptide assemblies for interacting with and organizing other biomolecules, such as DNA.

Main Methods:

• Computational prediction of peptide self-assembly behavior on graphene surfaces.
• Experimental self-assembly of designed peptides onto graphene and graphite substrates.
• Characterization of the resulting 2D peptide monolayer crystals using techniques sensitive to nanoscale structure and orientation.
• Investigation of DNA-peptide interactions and orientation on the assembled peptide surfaces.

Main Results:

• Designed peptides self-assembled into highly ordered, parallel, in-register β-sheets, termed 'β-tapes', on graphene surfaces, consistent with computational predictions.
• The atomic symmetry of the underlying graphene dictated the orientation of the β-tapes, aligning them along specific crystallographic directions.
• A cationic peptide assembly demonstrated strong adhesion to DNA, with preferential orientation of the DNA double helix along the β-tape axes.

Conclusions:

• Designed peptides can effectively amplify the atomic-level symmetry of graphene surfaces to the micrometer scale, creating ordered 2D structures.
• These peptide assemblies provide long-range directional order, enabling controlled organization of other molecules like DNA.
• The stability and ordering capabilities suggest potential applications in catalysis, biological interfaces, and DNA-peptide interaction studies.