title: Phosphate conversion coating reduces the degradation rate and suppresses side effects of metallic magnesium implants in an animal model.
abstract: Magnesium alloys have promising mechanical and biological properties for the development of degradable implants. However, rapid implant corrosion and gas accumulations in tissue impede clinical applications. With time, the implant degradation rate is reduced by a highly biocompatible, phosphate-containing corrosion layer. To circumvent initial side effects after implantation it was attempted to develop a simple in vitro procedure to generate a similarly protective phosphate corrosion layer. To this end magnesium samples were pre-incubated in phosphate solutions. The resulting coating was well adherent during routine handling procedures. It completely suppressed the initial burst of corrosion and it reduced the average in vitro magnesium degradation rate over 56 days almost two-fold. In a small animal model phosphate coatings on magnesium implants were highly biocompatible and abrogated the appearance of gas cavities in the tissue. After implantation, the phosphate coating was replaced by a layer with an elemental composition that was highly similar to the corrosion layer that had formed on plain magnesium implants. The data demonstrate that a simple pre-treatment could improve clinically relevant properties of magnesium-based implants. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1622-1635, 2017.
authors.affiliation: Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany.
authors.forename: Muhammad Imran
authors.initials: MI
authors.lastname: Rahim
authors.affiliation: Institute for Multiphase Processes, Leibniz University of Hannover, Appelstrasse 11, 30167, Hannover, Germany.
authors.forename: Ana
authors.initials: A
authors.lastname: Tavares
authors.affiliation: Institute for Multiphase Processes, Leibniz University of Hannover, Appelstrasse 11, 30167, Hannover, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Evertz
authors.affiliation: Institute for Inorganic Chemistry, Leibniz University of Hannover, Callinstrasse 9, 30167, Hannover, Germany.
authors.forename: Marc
authors.initials: M
authors.lastname: Kieke
authors.affiliation: Institute of Materials Science, Leibniz University of Hannover, An der Universität 2, 30823, Garbsen, Germany.|Department of Materials Science and Engineering, Michigan Technological University, 1400 Townsend Dr., Houghton, Michigan, 49931.
authors.forename: Jan-Marten
authors.initials: JM
authors.lastname: Seitz
authors.affiliation: Institute of Materials Science, Leibniz University of Hannover, An der Universität 2, 30823, Garbsen, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Eifler
authors.affiliation: CrossBIT, Center for Biocompatibility and Implant-Immunology, Department of Orthopedic Surgery, Hannover Medical School, Feodor-Lynen-Strasse 31, 30625, Hannover, Germany.|Laboratory for Biomechanics and Biomaterials, Department of Orthopedic Surgery, Hannover Medical School, Anna-von-Borries-Strasse 1-7, 30625, Hannover, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Weizbauer
authors.affiliation: CrossBIT, Center for Biocompatibility and Implant-Immunology, Department of Orthopedic Surgery, Hannover Medical School, Feodor-Lynen-Strasse 31, 30625, Hannover, Germany.|Laboratory for Biomechanics and Biomaterials, Department of Orthopedic Surgery, Hannover Medical School, Anna-von-Borries-Strasse 1-7, 30625, Hannover, Germany.
authors.forename: Elmar
authors.initials: E
authors.lastname: Willbold
authors.affiliation: Institute of Materials Science, Leibniz University of Hannover, An der Universität 2, 30823, Garbsen, Germany.
authors.forename: Hans
authors.initials: H
authors.lastname: Jürgen Maier
authors.affiliation: Institute for Multiphase Processes, Leibniz University of Hannover, Appelstrasse 11, 30167, Hannover, Germany.
authors.forename: Birgit
authors.initials: B
authors.lastname: Glasmacher
authors.affiliation: Institute for Inorganic Chemistry, Leibniz University of Hannover, Callinstrasse 9, 30167, Hannover, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Behrens
authors.affiliation: Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany.
authors.forename: Hansjörg
authors.initials: H
authors.lastname: Hauser
authors.affiliation: Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany.
authors.forename: Peter P
authors.initials: PP
authors.lastname: Mueller
mesh_terms: D000818:Animals; D020099:Coated Materials, Biocompatible / Q000737:chemistry / Q000494:pharmacology; D003343:Corrosion; D005260:Female; D020007:Implants, Experimental; D008274:Magnesium / Q000737:chemistry / Q000494:pharmacology; D008422:Materials Testing; D051379:Mice; D008807:Mice, Inbred BALB C; D010710:Phosphates / Q000737:chemistry / Q000494:pharmacology
chemical_list: D020099:Coated Materials, Biocompatible; D010710:Phosphates; D008274:Magnesium
keywords: animal model; biodegradation; coating; metal alloys; newberyite