Title: Multi-scale directed surface topography machined by electro discharge machining in combination with plasma electrolytic conversion for improved osseointegration

Authors: Fritz Klocke; Max Schwade; David Welling; Alexander Kopp

Addresses: Laboratory for Machine Tools and Production Engineering (WZL), RWTH Aachen University, Steinbachstr. 19, 52074 Aachen, Germany ' Laboratory for Machine Tools and Production Engineering (WZL), RWTH Aachen University, Steinbachstr. 19, 52074 Aachen, Germany ' Laboratory for Machine Tools and Production Engineering (WZL), RWTH Aachen University, Steinbachstr. 19, 52074 Aachen, Germany ' Meotec GmbH & Co. KG, Pauwelsstr. 17, 52074 Aachen, Germany

Abstract: Major deficits concerning biodegradable and non-biodegradable orthopaedic implants are a result of insufficient osseointegration and an accelerated corrosion rate. These in turn are significantly influenced by the surface tissue-interface. Cells belonging to different steps of the osteoblast differentiation cascade respond differently to the same surface structure. Therefore, a combination of particular micro and macro structures resulting in a multi-scale directed surface topography may significantly improve the cell response throughout the whole osseointegration process. This paper proposes the possibility to adapt the structural properties of a surface independently throughout different magnitudes of topography by a combination of electro discharge machining and a plasma electrolytic conversion process. Examples of such structures are demonstrated in samples made of the magnesium alloy WE43 as well as the most commonly used titanium alloy for orthopaedic implants Ti6Al4V.

Keywords: electro-discharge machining; EDM; wire-EDM; sinking-EDM; electrical discharge machining; plasma electrolytic conversion; PEC; surface topography; osseointegration; medical devices; orthopaedic implants; corrosion rate; cell response; biomedical engineering; bioengineering; magnesium alloys; alloys.

DOI: 10.1504/IJMMS.2013.056452

International Journal of Mechatronics and Manufacturing Systems, 2013 Vol.6 No.3, pp.254 - 269

Received: 11 Sep 2012
Accepted: 29 Jan 2013
Published online: 12 Jul 2014 *

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