Mechanically- and chemically-active antibacterial coatings

Nadine Ziegler, Ruhr University Bochum, Bochum, Deutschland
Christina Sengstock, University Hospital Bergmannsheil, 44789 Bochum, Deutschland
Manfred Köller, University Hospital Bochum, Bochum,
Kristina Tschulik, Ruhr University Bochum, Bochum,
Alfred Ludwig, Ruhr-University Bochum, Bochum,

Serious clinical infections can be caused by bacteria adhering to surfaces of medical devices and implants. To reduce implant associated infections, implant materials with antibacterial properties as well as good tissue compatibility are an urgent need. Their development is guided by strategies that inhibit initial bacterial colonization and reduce biofilm formation, e.g. by surface functionalization, either by selective surface structuring or by coatings showing chemical functionality. This study follows both approaches. The surface structuring is bioinspired from the nanocolumnar structures on cicada wings which show antibacterial properties. This study is a biomimetic approach to implement these nanocolumnar structures to clinically used implant surfaces. The structures were successfully fabricated by glancing angle deposition (GLAD) magnetron sputtering and are effective against gram-negative bacteria (E. coli). Microstructure and fluorescence microscopy show, that a mechanical effect similar to that on the cicada wing created the antibacterial property. In addition to the mechanical effect this study additionally includes a chemical antibacterial activity via the release of Ag+ ions. Silver shows the ability to kill gram-negative as well as gram-positive bacteria (chemical effect). To control the release of Ag+ from antibacterial surfaces, a sacrificial anode concept was realized.

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