title: Antibacterial efficacy of ultrahigh molecular weight polyethylene with silver containing diamond-like surface layers.
abstract: Antibacterial coating of medical devices is a promising approach to reduce the risk of infection but has not yet been achieved on wear surfaces, e.g. polyethylene (PE). We quantitatively determined the antimicrobial potency of different PE surfaces, which had been conversed to diamond-like carbon (DLC-PE) and doped with silver ions (Ag-DLC-PE). Bacterial adhesion and planktonic growth of various strains of S. epidermidis on Ag-DLC-PE were compared to untreated PE by quantification of colony forming units on the adherent surface and in the growth medium as well as semiquantitatively by determining the grade of biofilm formation by scanning electron microscopy. (1) A significant (p < 0.05) antimicrobial effect could be found for Ag-DLC-PE. (2) The antimicrobial effect was positively correlated with the applied fluences of Ag (fivefold reduced bacterial surface growth and fourfold reduced bacterial concentration in the surrounding medium with fluences of 1 × 10(17) vs. 1 × 10(16) cm(-2) under implantation energy of 10 keV). (3) A low depth of Ag penetration using low ion energies (10 or 20 vs. 100 keV) led to evident antimicrobial effects (fourfold reduced bacterial surface growth and twofold reduced bacterial concentration in the surrounding medium with 10 or 20 keV and 1 × 10(17) cm(-2) vs. no reduction of growth with 100 keV and 1 × 10(17) cm(-2)). (4) Biofilm formation was decreased by Ag-DLC-PE surfaces. The results obtained in this study suggest that PE-surfaces can be equipped with antibacterial effects and may provide a promising platform to finally add antibacterial coatings on wear surfaces of joint prostheses.
authors.affiliation: Clinic of Orthopedics and Sports Orthopedics, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Str. 22, 81675, Munich, Germany. norbert.harrasser@mri.tum.de.
authors.forename: Norbert
authors.initials: N
authors.lastname: Harrasser
authors.affiliation: Clinic of Orthopedics and Sports Orthopedics, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Str. 22, 81675, Munich, Germany. sebastian.juessen@mri.tum.de.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Jüssen
authors.affiliation: Clinic of Orthopedics and Sports Orthopedics, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Str. 22, 81675, Munich, Germany. ingo.banke@mri.tum.de.
authors.forename: Ingo J
authors.initials: IJ
authors.lastname: Banke
authors.affiliation: Experimental Physics IV, Institut für Physik, Augsburg University, Universitätsstr. 1, 86135, Augsburg, Germany. ralfkmeth@aol.com.
authors.forename: Ralf
authors.initials: R
authors.lastname: Kmeth
authors.affiliation: Clinic of Orthopedics and Sports Orthopedics, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Str. 22, 81675, Munich, Germany. eisenhart@tum.de.
authors.forename: Ruediger
authors.initials: R
authors.lastname: von Eisenhart-Rothe
authors.affiliation: Experimental Physics IV, Institut für Physik, Augsburg University, Universitätsstr. 1, 86135, Augsburg, Germany. stritzker@physik.uni-augsburg.de.
authors.forename: Bernd
authors.initials: B
authors.lastname: Stritzker
authors.affiliation: Clinic of Orthopedics and Sports Orthopedics, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Str. 22, 81675, Munich, Germany. hans.gollwitzer@mri.tum.de.|ATOS Clinic, Effnerstr. 38, 81925, Munich, Germany. hans.gollwitzer@mri.tum.de.
authors.forename: Hans
authors.initials: H
authors.lastname: Gollwitzer
authors.affiliation: Clinic of Orthopedics and Sports Orthopedics, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Str. 22, 81675, Munich, Germany. burgkart@tum.de.
authors.forename: Rainer
authors.initials: R
authors.lastname: Burgkart
keywords: Antibacterial coating; Diamond-like carbon; Implant-associated infections; Silver; Staphylococcus epidermidis