title: Electrostatic force microscopy of self-assembled peptide structures.
abstract: In this report electrostatic force microscopy (EFM) is used to study different peptide self-assembled structures such as tubes and particles. It is shown that not only geometrical information can be obtained using EFM, but also information about the composition of different structures. In particular we use EFM to investigate the structures of diphenylalanine peptide tubes, particles, and CSGAITIG peptide particles placed on pre-fabricated SiO(2) surfaces with a backgate. We show that the cavity in the peptide tubes could be due to the presence of water residues. Additionally we show that self-assembled amyloid peptides form spherical solid structures containing the same self-assembled peptide in its interior. In both cases transmission electron microscopy is used to verify these structures. Further, the limitations of the EFM technique are discussed, especially when the observed structures become small compared with the radius of the AFM tip used. Finally, an agreement between the detected signal and the structure of the hollow peptide tubes is demonstrated.
authors.affiliation: DTU Nanotech-Department of Micro- and Nanotechnology, Technical University of Denmark, Lyngby, Denmark.
authors.forename: Casper Hyttel
authors.initials: CH
authors.lastname: Clausen
authors.forename: Maria
authors.initials: M
authors.lastname: Dimaki
authors.forename: Spyros Pantoleon
authors.initials: SP
authors.lastname: Panagos
authors.forename: Emmanouil
authors.initials: E
authors.lastname: Kasotakis
authors.forename: Anna
authors.initials: A
authors.lastname: Mitraki
authors.forename: Winnie Edith
authors.initials: WE
authors.lastname: Svendsen
authors.forename: Jaime
authors.initials: J
authors.lastname: Castillo-León
mesh_terms: D000256:Adenoviridae / Q000737:chemistry; D004151:Dipeptides; D018625:Microscopy, Atomic Force / Q000379:methods*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D045333:Nanotubes, Peptide / Q000737:chemistry / Q000648:ultrastructure*; D010455:Peptides / Q000737:chemistry*; D010649:Phenylalanine / Q000031:analogs & derivatives / Q000737:chemistry; D020005:Propanols / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D012996:Solutions / Q000737:chemistry; D055672:Static Electricity; D014764:Viral Proteins / Q000737:chemistry; D014867:Water / Q000737:chemistry; D006845:Hydrocarbons, Fluorinated
chemical_list: D004151:Dipeptides; D045333:Nanotubes, Peptide; D010455:Peptides; D010649:Phenylalanine; D020005:Propanols; D012822:Silicon Dioxide; D012996:Solutions; D014764:Viral Proteins; D014867:Water; C026650:phenylalanylphenylalanine; C001337:hexafluoroisopropanol; D006845:Hydrocarbons, Fluorinated