title: Fabrication of a new substrate for atomic force microscopic observation of DNA molecules from an ultrasmooth sapphire plate.
abstract: A new stable substrate applicable to the observation of DNA molecules by atomic force microscopy (AFM) was fabricated from a ultrasmooth sapphire (alpha-Al2O3 single crystal) plate. The atomically ultrasmooth sapphire as obtained by high-temperature annealing has hydrophobic surfaces and could not be used for the AFM observation of DNA. However, sapphire treated with Na3PO4 aqueous solution exhibited a hydrophilic character while maintaining a smooth surface structure. The surface of the wet-treated sapphire was found by x-ray photoelectron spectroscopy and AFM to be approximately 0.3 nm. The hydrophilic surface character of the ultrasmooth sapphire plate made it easy for DNA molecules to adhere to the plate. Circular molecules of the plasmid DNA could be imaged by AFM on the hydrophilic ultrasmooth sapphire plate.
authors.affiliation: Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Yoshida
authors.forename: M
authors.initials: M
authors.lastname: Yoshimoto
authors.forename: K
authors.initials: K
authors.lastname: Sasaki
authors.forename: T
authors.initials: T
authors.lastname: Ohnishi
authors.forename: T
authors.initials: T
authors.lastname: Ushiki
authors.forename: J
authors.initials: J
authors.lastname: Hitomi
authors.forename: S
authors.initials: S
authors.lastname: Yamamoto
authors.forename: M
authors.initials: M
authors.lastname: Sigeno
mesh_terms: D000537:Aluminum Oxide; D055592:Biophysical Phenomena; D001703:Biophysics; D004247:DNA / Q000648:ultrastructure*; D018625:Microscopy, Atomic Force / Q000295:instrumentation* / Q000379:methods; D010710:Phosphates; D010957:Plasmids / Q000648:ultrastructure; D012996:Solutions; D013499:Surface Properties; D014867:Water
chemical_list: D010710:Phosphates; D012996:Solutions; D014867:Water; D004247:DNA; D000537:Aluminum Oxide; C018279:sodium phosphate