Basic Study
Copyright ©The Author(s) 2017. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Transplant. Jun 24, 2017; 7(3): 193-202
Published online Jun 24, 2017. doi: 10.5500/wjt.v7.i3.193
Copper as an alternative antimicrobial coating for implants - An in vitro study
Claudia Bergemann, Sarah Zaatreh, Katharina Wegner, Kathleen Arndt, Andreas Podbielski, Rainer Bader, Cornelia Prinz, Ulrich Lembke, J Barbara Nebe
Claudia Bergemann, J Barbara Nebe, Department of Cell Biology, University Medical Center Rostock, 18057 Rostock, Germany
Sarah Zaatreh, Katharina Wegner, Rainer Bader, Biomechanics and Implant Technology Research Laboratory, University Medical Center Rostock, 18057 Rostock, Germany
Kathleen Arndt, Andreas Podbielski, Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Rostock, 18057 Rostock, Germany
Cornelia Prinz, Ulrich Lembke, DOT GmbH, 18059 Rostock, Germany
Author contributions: Bergemann C, Wegner K and Arndt K performed research study; Lembke U contributed material samples; Bergemann C, Wegner K and Arndt K analyzed data; Bergemann C, Zaatreh S and Wegner K wrote the manuscript; Podbielski A, Bader R, Prinz C and Nebe JB designed the study.
Supported by the Federal Ministry of Education and Research of Germany (BMBF, project CEMOSTOBAS), No. 13N12105.
Institutional review board statement: This study does not involve any human or animal subjects.
Institutional animal care and use committee statement: This study does not involve any animal subjects.
Conflict-of-interest statement: To the best of authors’ knowledge, no conflict of interest exists.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Dr. J Barbara Nebe, Professor, Department of Cell Biology, University Medical Center Rostock, Schillingallee 69, 18057 Rostock, Germany. barbara.nebe@med.uni-rostock.de
Telephone: +49-381-4947771 Fax: +49-381-4947764
Received: November 28, 2016
Peer-review started: December 3, 2016
First decision: March 28, 2017
Revised: April 25, 2017
Accepted: May 12, 2017
Article in press: May 15, 2017
Published online: June 24, 2017
Processing time: 206 Days and 8.6 Hours
Abstract
AIM

To investigate osteoconductive and antimicrobial properties of a titanium-copper-nitride (TiCuN) film and an additional BONIT® coating on titanium substrates.

METHODS

For micro-structuring, the surface of titanium test samples was modified by titanium plasma spray (TPS). On the TPS-coated samples, the TiCuN layer was deposited by physical vapor deposition. The BONIT® layer was coated electrochemically. The concentration of copper ions released from TiCuN films was measured by atomic absorption spectrometry. MG-63 osteoblasts on TiCuN and BONIT® were analyzed for cell adhesion, viability and spreading. In parallel, Staphylococcus epidermidis (S. epidermidis) were cultivated on the samples and planktonic and biofilm-bound bacteria were quantified by counting of the colony-forming units.

RESULTS

Field emission scanning electron microscopy (FESEM) revealed rough surfaces for TPS and TiCuN and a special crystalline surface structure on TiCuN + BONIT®. TiCuN released high amounts of copper quickly within 24 h. These release dynamics were accompanied by complete growth inhibition of bacteria and after 2 d, no planktonic or adherent S. epidermidis were found on these samples. On the other hand viability of MG-63 cells was impaired during direct cultivation on the samples within 24 h. However, high cell colonization could be found after a 24 h pre-incubation step in cell culture medium simulating the in vivo dynamics closer. On pre-incubated TiCuN, the osteoblasts span the ridges and demonstrate a flattened, well-spread phenotype. The additional BONIT®coating reduced the copper release of the TiCuN layer significantly and showed a positive effect on the initial cell adhesion.

CONCLUSION

The TiCuNcoating inhibits the formation of bacterial biofilms on orthopedic implants by influencing the “race for the surface” to the advantage of osteoblasts.

Keywords: Implant-coating; Antimicrobial effect; Titanium plasma spray; Titanium-copper-nitride; BONIT®; Osteoconductivity

Core tip: Implant-associated infection is the most feared complication after joint replacement. We investigated the osteoconductive and antimicrobial properties of a titanium-copper-nitride (TiCuN) film and an additional BONIT® coating on titanium. TiCuN released high amounts of copper quickly within 24 h and after 2 d, no planktonic or adherent Staphylococcus epidermidis were found on these samples. A high colonization by osteoblast-like MG-63 cells was found after pre-incubation in medium for 24 h. TiCuN inhibits the formation of bacterial bio-films on orthopedic implants by influencing the “race for the surface” to the advantage of osteoblasts.