title: Differential magnesium implant corrosion coat formation and contribution to bone bonding.
abstract: Magnesium alloys are presently under investigation as promising biodegradable implant materials with osteoconductive properties. To study the molecular mechanisms involved, the potential contribution of soluble magnesium corrosion products to the stimulation of osteoblastic cell differentiation was examined. However, no evidence for the stimulation of osteoblast differentiation could be obtained when cultured mesenchymal precursor cells were differentiated in the presence of metallic magnesium or in cell culture medium containing elevated magnesium ion levels. Similarly, in soft tissue no bone induction by metallic magnesium or by the corrosion product magnesium hydroxide could be observed in a mouse model. Motivated by the comparatively rapid accumulation solid corrosion products physicochemical processes were examined as an alternative mechanism to explain the stimulation of bone growth by magnesium-based implants. During exposure to physiological solutions a structured corrosion coat formed on magnesium whereby the elements calcium and phosphate were enriched in the outermost layer which could play a role in the established biocompatible behavior of magnesium implants. When magnesium pins were inserted into avital bones, corrosion lead to increases in the pull out force, suggesting that the expanding corrosion layer was interlocking with the surrounding bone. Since mechanical stress is a well-established inducer of bone growth, volume increases caused by the rapid accumulation of corrosion products and the resulting force development could be a key mechanism and provide an explanation for the observed stimulatory effects of magnesium-based implants in hard tissue. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 697-709, 2017.
authors: Helmholtz Centre for Infection Research, Inhoffenstrasse 7, Braunschweig, 38124, Germany.
authors: Muhammad Imran
authors: MI
authors: Rahim
authors: CrossBIT, Center for Biocompatibility and Implant-Immunology, Department of Orthopedic Surgery, Hannover Medical School, Feodor-Lynen-Strasse 31, Hannover, 30625, Germany.|Laboratory for Biomechanics and Biomaterials, Department of Orthopedic Surgery, Hannover Medical School, Anna-von-Borries-Strasse 1-7, Hannover, 30625, Germany.
authors: Andreas
authors: A
authors: Weizbauer
authors: Institute for Multiphase Processes, Leibniz University of Hannover, Appelstraße 11, Hannover, 30167, Germany.
authors: Florian
authors: F
authors: Evertz
authors: Helmholtz Centre for Infection Research, Inhoffenstrasse 7, Braunschweig, 38124, Germany.|Laboratory for Biomechanics and Biomaterials, Department of Orthopedic Surgery, Hannover Medical School, Anna-von-Borries-Strasse 1-7, Hannover, 30625, Germany.
authors: Andrea
authors: A
authors: Hoffmann
authors: Helmholtz Centre for Infection Research, Inhoffenstrasse 7, Braunschweig, 38124, Germany.
authors: Manfred
authors: M
authors: Rohde
authors: Institute for Multiphase Processes, Leibniz University of Hannover, Appelstraße 11, Hannover, 30167, Germany.
authors: Birgit
authors: B
authors: Glasmacher
authors: CrossBIT, Center for Biocompatibility and Implant-Immunology, Department of Orthopedic Surgery, Hannover Medical School, Feodor-Lynen-Strasse 31, Hannover, 30625, Germany.|Laboratory for Biomechanics and Biomaterials, Department of Orthopedic Surgery, Hannover Medical School, Anna-von-Borries-Strasse 1-7, Hannover, 30625, Germany.
authors: Henning
authors: H
authors: Windhagen
authors: Helmholtz Centre for Infection Research, Inhoffenstrasse 7, Braunschweig, 38124, Germany.
authors: Gerhard
authors: G
authors: Gross
authors: Institute for Material Science Leibniz University of Hannover, Callinstrasse 9, Hannover, 30167, Germany.|Department of Materials Science and Engineering, Michigan Technological University, 1400 Townsend Dr, Houghton, Michigan, 49931.
authors: Jan-Marten
authors: JM
authors: Seitz
authors: Helmholtz Centre for Infection Research, Inhoffenstrasse 7, Braunschweig, 38124, Germany.
authors: Peter P
authors: PP
authors: Mueller
mesh_terms: D000818:Animals; D002460:Cell Line; D003343:Corrosion; D005260:Female; D020007:Implants, Experimental; D008274:Magnesium / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D059630:Mesenchymal Stem Cells / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D013131:Spine / Q000378:metabolism*
chemical_list: D008274:Magnesium
keywords: bone remodeling; magnesium corrosion layer; mechanical stress load; osseointegration; pull out force