Structure of a Peptide Adsorbed on Graphene and Graphite

• Published in: Nano letters 2012-05, Vol.12 (5), p.2342-2346
• Main Authors: Katoch, Jyoti, Kim, Sang Nyon, Kuang, Zhifeng, Farmer, Barry L, Naik, Rajesh R, Tatulian, Suren A, Ishigami, Masa
• Format: Article
• Language: English
• Subjects: Adsorption; Atomic structure; Biomolecules; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Fullerenes and related materials; diamonds, graphite; General equipment and techniques; Graphene; Graphite; Graphite - chemistry; Helical; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Materials science; Microscopy, Atomic Force; Molecular dynamics; Molecular structure; Peptides; Peptides - chemistry; Physics; Protein Conformation; Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing; Specific materials; Surface chemistry
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl300286k

Noncovalent functionalization of graphene using peptides is a promising method for producing novel sensors with high sensitivity and selectivity. Here we perform atomic force microscopy, Raman spectroscopy, infrared spectroscopy, and molecular dynamics simulations to investigate peptide-binding behavior to graphene and graphite. We studied a dodecamer peptide identified with phage display to possess affinity for graphite. Optical spectroscopy reveals that the peptide forms secondary structures both in powder form and in an aqueous medium. The dominant structure in the powder form is α-helix, which undergoes a transition to a distorted helical structure in aqueous solution. The peptide forms a complex reticular structure upon adsorption on graphene and graphite, having a helical conformation different from α-helix due to its interaction with the surface. Our observation is consistent with our molecular dynamics calculations, and our study paves the way for rational functionalization of graphene using biomolecules with defined structures and, therefore, functionalities.