title: Graphene Biosensor Programming with Genetically Engineered Fusion Protein Monolayers.
abstract: We demonstrate a label-free biosensor concept based on specific receptor modules, which provide immobilization and selectivity to the desired analyte molecules, and on charge sensing with a graphene field effect transistor. The receptor modules are fusion proteins in which small hydrophobin proteins act as the anchor to immobilize the receptor moiety. The functionalization of the graphene sensor is a single-step process based on directed self-assembly of the receptor modules on a hydrophobic surface. The modules are produced separately in fungi or plants and purified before use. The modules form a dense and well-oriented monolayer on the graphene transistor channel and the receptor module monolayer can be removed, and a new module monolayer with a different selectivity can be assembled in situ. The receptor module monolayers survive drying, showing that the functionalized devices can be stored and have a reasonable shelf life. The sensor is tested with small charged peptides and large immunoglobulin molecules. The measured sensitivities are in the femtomolar range, and the response is relatively fast, of the order of one second.
authors.affiliation: VTT Technical Research Centre of Finland Ltd. , P.O. Box 1000, FI-02044 VTT, Espoo, Finland.
authors.forename: Miika
authors.initials: M
authors.lastname: Soikkeli
authors.affiliation: VTT Technical Research Centre of Finland Ltd. , P.O. Box 1000, FI-02044 VTT, Espoo, Finland.
authors.forename: Katri
authors.initials: K
authors.lastname: Kurppa
authors.affiliation: VTT Technical Research Centre of Finland Ltd. , P.O. Box 1000, FI-02044 VTT, Espoo, Finland.
authors.forename: Markku
authors.initials: M
authors.lastname: Kainlauri
authors.affiliation: VTT Technical Research Centre of Finland Ltd. , P.O. Box 1000, FI-02044 VTT, Espoo, Finland.
authors.forename: Sanna
authors.initials: S
authors.lastname: Arpiainen
authors.affiliation: VTT Technical Research Centre of Finland Ltd. , P.O. Box 1000, FI-02044 VTT, Espoo, Finland.
authors.forename: Arja
authors.initials: A
authors.lastname: Paananen
authors.affiliation: VTT Technical Research Centre of Finland Ltd. , P.O. Box 1000, FI-02044 VTT, Espoo, Finland.
authors.forename: David
authors.initials: D
authors.lastname: Gunnarsson
authors.affiliation: VTT Technical Research Centre of Finland Ltd. , P.O. Box 1000, FI-02044 VTT, Espoo, Finland.
authors.forename: Jussi J
authors.initials: JJ
authors.lastname: Joensuu
authors.affiliation: VTT Technical Research Centre of Finland Ltd. , P.O. Box 1000, FI-02044 VTT, Espoo, Finland.
authors.forename: Päivi
authors.initials: P
authors.lastname: Laaksonen
authors.affiliation: VTT Technical Research Centre of Finland Ltd. , P.O. Box 1000, FI-02044 VTT, Espoo, Finland.
authors.forename: Mika
authors.initials: M
authors.lastname: Prunnila
authors.affiliation: VTT Technical Research Centre of Finland Ltd. , P.O. Box 1000, FI-02044 VTT, Espoo, Finland.|School of Chemical Technology, Aalto University , P.O. Box 6100, FI-00076 AALTO, Espoo, Finland.
authors.forename: Markus B
authors.initials: MB
authors.lastname: Linder
authors.affiliation: VTT Technical Research Centre of Finland Ltd. , P.O. Box 1000, FI-02044 VTT, Espoo, Finland.
authors.forename: Jouni
authors.initials: J
authors.lastname: Ahopelto
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D015202:Protein Engineering; D011993:Recombinant Fusion Proteins / Q000032:analysis* / Q000737:chemistry / Q000235:genetics
chemical_list: D011993:Recombinant Fusion Proteins; D006108:Graphite
keywords: Debye length; biosensor; fusion protein; graphene; hydrophobin; self-assembly