title: Hydrophobic interaction governs unspecific adhesion of staphylococci: a single cell force spectroscopy study.
abstract: Unspecific adhesion of bacteria is usually the first step in the formation of biofilms on abiotic surfaces, yet it is unclear up to now which forces are governing this process. Alongside long-ranged van der Waals and electrostatic forces, short-ranged hydrophobic interaction plays an important role. To characterize the forces involved during approach and retraction of an individual bacterium to and from a surface, single cell force spectroscopy is applied: A single cell of the apathogenic species Staphylococcus carnosus isolate TM300 is used as bacterial probe. With the exact same bacterium, hydrophobic and hydrophilic surfaces can be probed and compared. We find that as far as 50 nm from the surface, attractive forces can already be recorded, an indication of the involvement of long-ranged forces. Yet, comparing the surfaces of different surface energy, our results corroborate the model that large, bacterial cell wall proteins are responsible for adhesion, and that their interplay with the short-ranged hydrophobic interaction of the involved surfaces is mainly responsible for adhesion. The ostensibly long range of the attraction is a result of the large size of the cell wall proteins, searching for contact via hydrophobic interaction. The model also explains the strong (weak) adhesion of S. carnosus to hydrophobic (hydrophilic) surfaces.
authors.affiliation: Experimental Physics, Campus E2 9, Saarland University, D-66123 Saarbrücken, Germany.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Thewes
authors.affiliation: Experimental Physics, Campus E2 9, Saarland University, D-66123 Saarbrücken, Germany ; Present address: Dept. of Bioengineering and California Institute for Quantitative Biosciences (QB3), University of California at Berkeley, Berkeley, California 94720, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Loskill
authors.affiliation: Institute of Medical Microbiology and Hygiene, Saarland University, D-66421 Homburg/Saar, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Jung
authors.affiliation: Institute of Medical Microbiology and Hygiene, Saarland University, D-66421 Homburg/Saar, Germany.
authors.forename: Henrik
authors.initials: H
authors.lastname: Peisker
authors.affiliation: Institute of Medical Microbiology and Hygiene, Saarland University, D-66421 Homburg/Saar, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Bischoff
authors.affiliation: Institute of Medical Microbiology and Hygiene, Saarland University, D-66421 Homburg/Saar, Germany.
authors.forename: Mathias
authors.initials: M
authors.lastname: Herrmann
authors.affiliation: Experimental Physics, Campus E2 9, Saarland University, D-66123 Saarbrücken, Germany.
authors.forename: Karin
authors.initials: K
authors.lastname: Jacobs
keywords: Staphylococcus carnosus; atomic force microscopy (AFM); force spectroscopy; hydrophobic interaction; single cell