title: Surface force and vibrational spectroscopic analyses of interfacial water molecules in the vicinity of methoxy-tri(ethylene glycol)-terminated monolayers: mechanisms underlying the effect of lateral packing density on bioinertness.
abstract: Unequivocal dependence of bioinertness of self-assembled monolayers of methoxy-tri(ethylene glycol)-terminated alkanethiol (EG3-OMe SAMs) on their packing density has been a mystery for more than two decades. We tackled this long-standing question by performing surface force and surface-enhanced infrared absorption (SEIRA) spectroscopic measurements. Our surface force measurements revealed a physical barrier of interfacial water in the vicinity of the Au-supported EG3-OMe SAM (low packing density), whereas the Ag-supported one (high packing density) did not possess such interfacial water. In addition, the results of SEIRA measurements clearly exhibited that hydrogen bonding states of the interfacial water differ depending on the substrates. We also characterized the bioinertness of these SAMs by protein adsorption tests and adhesion assays of platelet and human umbilical vein endothelial cells. The hydrogen bonding states of the interfacial water and water-induced interaction clearly correlated with the bioinertness of the SAMs, suggesting that the interfacial water plays an important role determining the interaction of the SAMs with biomolecules and cells.
authors.affiliation: a Department of Materials Science and Engineering , Tokyo Institute of Technology , Tokyo , Japan.
authors.forename: Taito
authors.initials: T
authors.lastname: Sekine
authors.affiliation: a Department of Materials Science and Engineering , Tokyo Institute of Technology , Tokyo , Japan.
authors.forename: Syifa
authors.initials: S
authors.lastname: Asatyas
authors.affiliation: b Department of Biochemical Engineering , Yamagata University , Yamagata , Japan.
authors.forename: Chikako
authors.initials: C
authors.lastname: Sato
authors.affiliation: c Department of Engineering Science , Osaka Electro-Communication University , Osaka , Japan.
authors.forename: Shigeaki
authors.initials: S
authors.lastname: Morita
authors.affiliation: b Department of Biochemical Engineering , Yamagata University , Yamagata , Japan.|d Institute for Materials Chemistry and Engineering , Kyushu University , Fukuoka , Japan.
authors.forename: Masaru
authors.initials: M
authors.lastname: Tanaka
authors.affiliation: a Department of Materials Science and Engineering , Tokyo Institute of Technology , Tokyo , Japan.|e Surface and Interface Science Laboratory , RIKEN , Saitama , Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Hayashi
mesh_terms: D000327:Adsorption; D002448:Cell Adhesion / Q000187:drug effects; D019855:Ethylene Glycol / Q000737:chemistry* / Q000494:pharmacology*; D005340:Fibrinogen / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D061307:Human Umbilical Vein Endothelial Cells / Q000166:cytology / Q000187:drug effects; D006801:Humans; D006860:Hydrogen Bonding; D012834:Silver / Q000737:chemistry; D013057:Spectrum Analysis; D013329:Structure-Activity Relationship; D013499:Surface Properties; D014732:Vibration; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water; D012834:Silver; D006046:Gold; D005340:Fibrinogen; D019855:Ethylene Glycol
keywords: Bioinertness; atomic force microscopy; oligo(ethylene glycol); self-assembled monolayers; surface forces; surface-enhanced infrared adsorption spectroscopy; water