title: Subsurface influence on the structure of protein adsorbates as revealed by in situ X-ray reflectivity.
abstract: The adsorption process of proteins to surfaces is governed by the mutual interactions among proteins, the solution, and the substrate. Interactions arising from the substrate are usually attributed to the uppermost atomic layer. This actual surface defines the surface chemistry and hence steric and electrostatic interactions. For a comprehensive understanding, however, the interactions arising from the bulk material also have to be considered. Our protein adsorption experiments with globular proteins (α-amylase, bovine serum albumin, and lysozyme) clearly reveal the influence of the subsurface material via van der Waals forces. Here, a set of functionalized silicon wafers enables a distinction between the effects of surface chemistry and the subsurface composition of the substrate. Whereas the surface chemistry controls whether the individual proteins are denatured, the strength of the van der Waals forces affects the final layer density and hence the adsorbed amount of proteins. The results imply that van der Waals forces mainly influence surface processes, which govern the structure formation of the protein adsorbates, such as surface diffusion and spreading.
authors.affiliation: Department of Experimental Physics, Saarland University, 66041 Saarbrücken, Germany.
authors.forename: Hendrik
authors.initials: H
authors.lastname: Hähl
authors.forename: Florian
authors.initials: F
authors.lastname: Evers
authors.forename: Samuel
authors.initials: S
authors.lastname: Grandthyll
authors.forename: Michael
authors.initials: M
authors.lastname: Paulus
authors.forename: Christian
authors.initials: C
authors.lastname: Sternemann
authors.forename: Peter
authors.initials: P
authors.lastname: Loskill
authors.forename: Matthias
authors.initials: M
authors.lastname: Lessel
authors.forename: Anne K
authors.initials: AK
authors.lastname: Hüsecken
authors.forename: Thorsten
authors.initials: T
authors.lastname: Brenner
authors.forename: Metin
authors.initials: M
authors.lastname: Tolan
authors.forename: Karin
authors.initials: K
authors.lastname: Jacobs
mesh_terms: D000327:Adsorption; D000818:Animals; D002417:Cattle; D006801:Humans; D011506:Proteins / Q000737:chemistry*; D013499:Surface Properties; D014961:X-Ray Diffraction
chemical_list: D011506:Proteins