Structure of a Peptide Adsorbed on Graphene and Graphite

Abstract

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.

Sensing at the Surface of Graphene Field‐Effect Transistors

“…[12] The broad sensing potential of graphene can only be unlocked by the introduction of sensitizer (bio)molecules and structures, e.g. various inorganic groups, [23][24][25][81][82][83][84][85][86][87][88][89][90] organic or organometallic molecules, [37,[91][92][93][94][95][96] DNAs, [97][98][99][100][101] proteins, [102] peptides, [30,31,103,104] nanoparticles, [105,106,107] and 2D heterostructure. [51,52,61,108] These molecules are able to respond chemically or physically to their nearby environment, whose responses could then be transduced into an appreciable change in the conductivity of the carbon-based honeycomb scaffold.…”

“…The introduction of such chemical moieties on the graphene surface or edge is often referred to as graphene functionalization. [109,110] Chemical functionalization of graphene is commonly achieved using either covalent [23][24][25][26][27]28] or non-covalent [29][30][31][32] strategies. The resulted graphene materials contain specific recognition moieties for biochemical sensing, but still share, to a large extent, the same carbon honeycomb backbone and the electrical properties, especially the field effect, of graphene.…”

“…3g). Besides DNA, proteins [102] or peptides [30,31] containing aromatic moieties could also self-assemble on a graphene scaffold. As illustrated in Fig.…”

“…This indicates that the adsorption occurred specifically on graphene. [31] Electrostatic interaction is another driving force of the non-covalent assembly. For instance, voltage-biased graphene can act as an electrophoretic electrode for immobilization of charged biomolecules.…”

“…[22] Additionally, graphene (at least ideal graphene) has a crystal lattice free of dangling bonds and is therefore intrinsically chemically inert. This inertness has been a driving force for the first attempts aiming at biointerfacing graphene with specific recognition moieties, via both covalent [23][24][25][26][27]28] and non-covalent [29][30][31][32] approaches, using different biochemical molecules and chemical treatments.…”