Recent advances in the development of graphene-based surface plasmon resonance (SPR) interfaces

Surface plasmon resonance (SPR) is a powerful technique for measurement of biomolecular interactions in real-time in a label-free environment. One of the most common techniques for plasmon excitation is the Kretschmann configuration, and numerous studies of ligand-analyte interactions have been performed on surfaces functionalized with a variety of biomolecules, for example DNA, RNA, glycans, proteins, and peptides. A significant limitation of SPR is that the substrate must be a thin metal film. Post-coating of the metal thin film with a thin dielectric top layer has been reported to enhance the performance of the SPR sensor, but is highly dependent on the thickness of the upper layer and its dielectric constant. Graphene is a single-atom thin planar sheet of sp2 carbon atoms perfectly arranged in a honeycomb lattice. Graphene and graphene oxide are good supports for biomolecules because of their large surface area and rich pi conjugation structure, making them suitable dielectric top layers for SPR sensing. In this paper, we review some of the key issues in the development of graphene-based SPR chips. The actual challenges of using these interfaces for studying biomolecular interactions will be discussed and the first examples of the use of graphene-on-metal SPR interfaces for biological sensing will be presented.