In vitro adhesion of staphylococci to diamond-like carbon polymer hybrids under dynamic flow conditions Antti Soininen • Jaakko Levon • Maria Katsikogianni • Katja Myllymaa • Reijo Lappalainen • Yrjo ¨ T. Konttinen • Teemu J. Kinnari • Veli-Matti Tiainen • Yannis Missirlis Received: 22 October 2010 / Accepted: 4 January 2011 / Published online: 18 January 2011 Ó Springer Science+Business Media, LLC 2011 Abstract This study compares the ability of selected materials to inhibit adhesion of two bacterial strains com- monly implicated in implant-related infections. These two strains are Staphylococcus aureus (S-15981) and Staphy- lococcus epidermidis (ATCC 35984). In experiments we tested six different materials, three conventional implant metals: titanium, tantalum and chromium, and three diamond-like carbon (DLC) coatings: DLC, DLC–poly- dimethylsiloxane hybrid (DLC–PDMS-h) and DLC–poly- tetrafluoroethylene hybrid (DLC–PTFE-h) coatings. DLC coating represents extremely hard material whereas DLC hybrids represent novel nanocomposite coatings. The two DLC polymer hybrid films were chosen for testing due to their hardness, corrosion resistance and extremely good non-stick (hydrophobic and oleophobic) properties. Bacte- rial adhesion assay tests were performed under dynamic flow conditions by using parallel plate flow chambers (PPFC). The results show that adhesion of S. aureus to DLC–PTFE-h and to tantalum was significantly (P \ 0.05) lower than to DLC–PDMS-h (0.671 ± 0.001 9 10 7 /cm 2 and 0.751 ± 0.002 9 10 7 /cm 2 vs. 1.055 ± 0.002 9 10 7 /cm 2 , respectively). No significant differences were detected between other tested materials. Hence DLC–PTFE-h coating showed as low susceptibility to S. aureus adhesion as all the tested conventional implant metals. The adherence of S. epidermidis to biomaterials was not significantly (P \ 0.05) different between the materials tested. This suggests that DLC–PTFE-h films could be used as a bio- material coating without increasing the risk of implant- related infections. 1 Introduction Infections associated with biomedical devices have serious consequences for the patients and inevitably increase costs to the society. Bacterial adhesion, colonization, and sub- sequent formation of resistant biofilms on an implant sur- face are the major reasons for implant-related infections of orthopedic implants [1–5]. These infections can usually be cured only by device removal, with antibiotics being used as a supportive therapy and for eradication. Because Staphylococcus aureus and Staphylococcus epidermidis are the most common causative pathogens associated with implant-related infections, these two bacteria were selected for probing of materials of interest [6–8]. As the implant or coating designed for clinical use will be subjected to body fluid flow, bacterial adhesion should be studied under Antti Soininen and Jaakko Levon contributed equally to this work. A. Soininen (&)  Y. T. Konttinen  V.-M. Tiainen ORTON Research Institute of the ORTON Orthopaedic Hospital, Tenholantie 10, 00280 Helsinki, Finland e-mail: antti.soininen@orton.fi J. Levon  Y. T. Konttinen Department of Medicine, Helsinki University Central Hospital, Helsinki, Finland M. Katsikogianni  Y. Missirlis Laboratory of Biomechanics and Biomedical Engineering, Department of Mechanical Engineering & Aeronautics, University of Patras, Patras, Greece K. Myllymaa  R. Lappalainen Department of Physics, University of Kuopio, Kuopio, Finland Y. T. Konttinen COXA Hospital for Joint Replacement, Tampere, Finland T. J. Kinnari Department of Otolaryngology, Helsinki University Central Hospital, Helsinki, Finland 123 J Mater Sci: Mater Med (2011) 22:629–636 DOI 10.1007/s10856-011-4231-9