title: The Effect of Hydrophobin Protein on Conductive Properties of Carbon Nanotube Field-Effect Transistors: First Study on Sensing Mechanism.
abstract: Hydrophobin is a surface active protein having both hydrophobic and hydrophilic functional domains which has previously been used for functionalization and solubilization of graphene and carbon nanotubes. In this work, field-effect transistors based on single nanotubes have been employed for electronic detection of hydrophobin protein in phosphate buffer solution. Individual nanotubes, single- and multiwalled, are characterized by atomic force microscopy after being immersed in protein solution, showing a relatively dense coverage with hydrophobin. We have studied aspects such as nanotube length (0.3-1.2 µm) and the hysteresis effect in the gate voltage dependent conduction. When measured in ambient condition after the exposure to hydrophobin, the resistance increase has a strong dependence on the nanotube length, which we ascribe to mobility degradation and localization effects. The change could be exceptionally large when measured in-situ in solution and at suitable gate voltage conditions, which is shown to relate to the different mechanism behind the hysteresis effect.
authors.forename: Peerapong
authors.initials: P
authors.lastname: Yotprayoonsakl
authors.forename: Géza R
authors.initials: GR
authors.lastname: Szilvay
authors.forename: Päivi
authors.initials: P
authors.lastname: Laaksonen
authors.forename: Markus B
authors.initials: MB
authors.lastname: Linder
authors.forename: Markus
authors.initials: M
authors.lastname: Ahlskog
mesh_terms: D004553:Electric Conductivity; D006046:Gold / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D053768:Metal Nanoparticles / Q000737:chemistry; D036103:Nanotechnology / Q000295:instrumentation*; D037742:Nanotubes, Carbon / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry*; D014173:Transistors, Electronic
chemical_list: D037742:Nanotubes, Carbon; D011506:Proteins; D006046:Gold