title: Influence of the subsurface composition of a material on the adhesion of  staphylococci.
abstract: Controlling the interface between bacteria and solid materials has become an important task in biomedical science. For a fundamental and comprehensive understanding of adhesion it is necessary to seek quantitative information about the involved interactions. Most studies concentrate on the modification of the surface (chemical composition, hydrophobicity, or topography) neglecting, however, the influence of the bulk material, which always contributes to the overall interaction via van der Waals forces. In this study, we applied AFM force spectroscopy and flow chamber experiments to probe the adhesion of  Staphylococcus carnosus  to a set of tailored Si wafers, allowing for a separation of short- and long-range forces. We provide experimental evidence that the subsurface composition of a substrate influences bacterial adhesion. A coarse estimation of the strength of the van der Waals forces via the involved Hamaker constants substantiates the experimental results. The results demonstrate that the uppermost layer is not solely responsible for the strength of adhesion. Rather, for all kinds of adhesion studies, it is equally important to consider the contribution of the subsurface.
authors.affiliation: Department of Experimental Physics, Saarland University, Saarbrücken, 66041, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Loskill
authors.forename: Hendrik
authors.initials: H
authors.lastname: Hähl
authors.forename: Nicolas
authors.initials: N
authors.lastname: Thewes
authors.forename: Christian Titus
authors.initials: CT
authors.lastname: Kreis
authors.forename: Markus
authors.initials: M
authors.lastname: Bischoff
authors.forename: Mathias
authors.initials: M
authors.lastname: Herrmann
authors.forename: Karin
authors.initials: K
authors.lastname: Jacobs
mesh_terms: D001422:Bacterial Adhesion; D001672:Biocompatible Materials / Q000737:chemistry; D018625:Microscopy, Atomic Force; D012822:Silicon Dioxide / Q000737:chemistry*; D013210:Staphylococcus / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D012822:Silicon Dioxide