Antibacterial potency of different deposition methods of silver and copper containing diamond-like carbon coated polyethylene

Norbert Harrasser,Bernd Stritzker,Hans Gollwitzer,Ralf Kmeth,Rainer Burgkart,Andreas Obermeir,Sebastian Jüssen

doi:10.1186/s40824-016-0062-6

Abstract

BackgroundAntibacterial coatings of medical devices have been introduced as a promising approach to reduce the risk of infection. In this context, diamond-like carbon coated polyethylene (DLC-PE) can be enriched with bactericidal ions and gain antimicrobial potency. So far, influence of different deposition methods and ions on antimicrobial effects of DLC-PE is unclear.MethodsWe quantitatively determined the antimicrobial potency of different PE surfaces treated with direct ion implantation (II) or plasma immersion ion implantation (PIII) and doped with silver (Ag-DLC-PE) or copper (Cu-DLC-PE). Bacterial adhesion and planktonic growth of various strains of S. epidermidis were evaluated by quantification of bacterial growth as well as semiquantitatively by determining the grade of biofilm formation by scanning electron microscopy (SEM). Additionally silver release kinetics of PIII-samples were detected.Results(1) A significant (p < 0.05) antimicrobial effect on PE-surface could be found for Ag- and Cu-DLC-PE compared to untreated PE. (2) The antimicrobial effect of Cu was significantly lower compared to Ag (reduction of bacterial growth by 0.8 (Ag) and 0.3 (Cu) logarithmic (log)-levels). (3) PIII as a deposition method was more effective in providing antibacterial potency to PE-surfaces than II alone (reduction of bacterial growth by 2.2 (surface) and 1.1 (surrounding medium) log-levels of PIII compared to 1.2 (surface) and 0.6 (medium) log-levels of II). (4) Biofilm formation was more decreased on PIII-surfaces compared to II-surfaces. (5) A silver-concentration-dependent release was observed on PIII-samples.ConclusionThe results obtained in this study suggest that PIII as a deposition method and Ag-DLC-PE as a surface have high bactericidal effects.

Highlights

Antibacterial coatings of medical devices have been introduced as a promising approach to reduce the risk of infection
The results obtained in this study suggest that plasma immersion ion implantation (PIII) as a deposition method and silver incorporated diamond-like carbon coating (Ag-diamond-like carbon (DLC))-PE as a surface have high bactericidal effects
Comparison of Cu- and AgDLC-PE samples among each other revealed a significant reduction of bacterial surface growth on Ag-DLC

Summary

Introduction

Antibacterial coatings of medical devices have been introduced as a promising approach to reduce the risk of infection In this context, diamond-like carbon coated polyethylene (DLC-PE) can be enriched with bactericidal ions and gain antimicrobial potency. DLC coatings can act as local antibacterial agents if release of Ag (Ag+)- or Cu (Cu++)-ions is provided [15,16,17], and at the same time exhibit excellent tribological features if used for hip or knee arthroplasty [18,19,20,21] In spite of these promising results, to our best knowledge, comprehensive studies on antibacterial effects of DLC coatings on soft wear surfaces, e.g. polyethylene (PE), comparing Ag and Cu have not been conducted so far. Data on the use of different deposition methods for DLC coatings and its influence on antimicrobial effects are still lacking

Methods

Results

Discussion

Conclusion