Measuring Molecular Adsorption on Graphitic Surfaces via Sprayed Graphene Field Effect Transistors

Abstract

The characterization of biomolecular adsorption is instrumental in applications such as biomedical implants and diagnostic devices. Graphitic surfaces such as graphene and pyrolytic graphite are prime candidates for these applications. However, a literature survey of adsorption characterization techniques shows a lack of scalable, high-throughput platforms for in-situ monitoring of biomolecular adsorption on graphitic surfaces. This thesis develops and evaluates a platform using sprayed graphene field effect transistors for in-situ tracking of biomolecular adsorption onto graphitic surfaces. The binding affinities of graphite-binding peptides to a graphitic surface were electrically characterized using sprayed graphene field effect transistors (SGFETs) fabricated with solution exfoliated graphene. The binding affinities of these peptides were also characterized using atomic force microscopy (AFM) and mechanically exfoliated graphene field effect transistors (GFETs) to confirm the validity of the SGFET platform. Binding constants obtained via GFET and AFM were comparable with those observed using SGFETs. The sprayed graphene film serves as a scalable platform to study biomolecular adsorption to graphitic surfaces.