title: Sum-frequency generation analyses of the structure of water at amphoteric SAM-liquid water interfaces.
abstract: Surfaces of both a cover glass and the flat plane of a semi-cylindrical quartz prism were modified with a mixture of positively and negatively charged silane coupling reagents (3-aminopropyltriethoxysilane (APTES) and 3-(trihydroxysilyl)propylmethylphosphonate (THPMP), respectively). The glass surface modified with a self-assembled monolayer (SAM) prepared at a mixing ratio of APTES:THPMP=4:6 was electrically almost neutral and was resistant to non-specific adsorption of proteins, whereas fibroblasts gradually adhered to an amphoteric (mixed) SAM surface probably due to its stiffness, though the number of adhered cells was relatively small. Sum frequency generation (SFG) spectra indicated that total intensity of the OH stretching region (3000-3600cm(-1)) for the amphoteric SAM-modified quartz immersed in liquid water was smaller than those for the positively and negatively charged SAM-modified quartz prisms and a bare quartz prism in contact with liquid water. These results suggested that water molecules at the interface of water and an amphoteric SAM-modified quartz prism are not strongly oriented in comparison with those at the interface of a lopsidedly charged SAM-modified quartz prism and bare quartz. The importance of charge neutralization for the anti-biofouling properties of solid materials was strongly suggested.
authors.affiliation: Department of Applied Chemistry, Graduate School of Science and Engineering, University of Toyama, Toyama 930-8555, Japan.
authors.forename: Kouji
authors.initials: K
authors.lastname: Nomura
authors.affiliation: Frontier Research Core for Life Sciences, University of Toyama, Toyama 930-8555, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Nakaji-Hirabayashi
authors.affiliation: Department of Applied Chemistry, Graduate School of Science and Engineering, University of Toyama, Toyama 930-8555, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Gemmei-Ide
authors.affiliation: Department of Applied Chemistry, Graduate School of Science and Engineering, University of Toyama, Toyama 930-8555, Japan. Electronic address: kitano@eng.u-toyama.ac.jp.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kitano
authors.affiliation: International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS) and Global Research Center for Environment and Energy Based on Nanomaterials Science (GREEN), Tsukuba 305-0044, Japan.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Noguchi
authors.affiliation: International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS) and Global Research Center for Environment and Energy Based on Nanomaterials Science (GREEN), Tsukuba 305-0044, Japan. Electronic address: uosaki.kohei@nims.go.jp.
authors.forename: Kohei
authors.initials: K
authors.lastname: Uosaki
mesh_terms: D000327:Adsorption; D000818:Animals; D002417:Cattle; D005898:Glass / Q000737:chemistry*; D051379:Mice; D041681:NIH 3T3 Cells; D063065:Organophosphonates / Q000737:chemistry; D056951:Photoelectron Spectroscopy; D011437:Propylamines; D011791:Quartz / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D012825:Silicon / Q000737:chemistry; D055672:Static Electricity; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
chemical_list: D063065:Organophosphonates; D011437:Propylamines; D012821:Silanes; D014867:Water; D011791:Quartz; D012710:Serum Albumin, Bovine; C477625:amino-propyl-triethoxysilane; D012825:Silicon
keywords: Amphoteric SAM; Biocompatibility; Orientation of water molecules; Silane coupling reaction; Sum frequency generation