title: Adsorption and nanowear properties of bovine submaxillary mucin films on solid surfaces: influence of solution pH and substrate hydrophobicity.
abstract: The adsorption and mechanical stability of bovine submaxillary mucins (BSM) films at solid-liquid interfaces were studied with respect to both substrate hydrophobicity and solution pH. Dynamic light scattering revealed a single peak distribution in neutral aqueous solution (pH 7.4) and a small fraction with enhanced aggregation was observed in acidic solution (pH 3.8). Both substrate hydrophobicity and solution pH were found to affect the spontaneous adsorption of BSM onto solid surfaces; BSM adsorbed more onto hydrophobic surfaces than hydrophilic ones, and adsorbed more at pH 3.8 than at pH 7.4. Thus, the highest "dry" adsorbed mass was observed for hydrophobic surfaces in pH 3.8 solution. However, a highest "wet" adsorbed mass, i.e. which includes the solvent coupled to the film, was observed for hydrophobic surfaces at pH 7.4. The mechanical stability of the films was studied at the nanoscale with an atomic force microscope operated in the friction force spectroscopy mode. Results revealed that BSM films formed on hydrophobic substrates were stronger than those formed on hydrophilic ones. Moreover, the film stability also depended on the ambient pH and stronger films were formed at acidic conditions, i.e. close to the BSM isoelectric point.
authors.affiliation: Department of Biomedical Sciences, Faculty of Health and Society, Malmö University, 20506 Malmoe, Sweden. Electronic address: javier.sotres@mah.se.
authors.forename: Javier
authors.initials: J
authors.lastname: Sotres
authors.affiliation: Department of Mechanical Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark. Electronic address: jbm@mek.dtu.dk.
authors.forename: Jan Busk
authors.initials: JB
authors.lastname: Madsen
authors.affiliation: Department of Biomedical Sciences, Faculty of Health and Society, Malmö University, 20506 Malmoe, Sweden. Electronic address: thomas.arnebrant@mah.se.
authors.forename: Thomas
authors.initials: T
authors.lastname: Arnebrant
authors.affiliation: Department of Mechanical Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark. Electronic address: seele@mek.dtu.dk.
authors.forename: Seunghwan
authors.initials: S
authors.lastname: Lee
mesh_terms: D000327:Adsorption; D000818:Animals; D002417:Cattle; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D008745:Methylation; D009077:Mucins / Q000737:chemistry / Q000302:isolation & purification*; D055550:Protein Stability; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D009077:Mucins; D012822:Silicon Dioxide
keywords: Adsorption; Bovine submaxillary mucin (BSM); Hydrophobicity; Nanowear; pH