title: Effect of the addition of low rare earth elements (lanthanum, neodymium, cerium) on the biodegradation and biocompatibility of magnesium.
abstract: Rare earth elements are promising alloying element candidates for magnesium alloys used as biodegradable devices in biomedical applications. Rare earth elements have significant effects on the high temperature strength as well as the creep resistance of alloys and they improve magnesium corrosion resistance. We focused on lanthanum, neodymium and cerium to produce magnesium alloys with commonly used rare earth element concentrations. We showed that low concentrations of rare earth elements do not promote bone growth inside a 750 μm broad area around the implant. However, increased bone growth was observed at a greater distance from the degrading alloys. Clinically and histologically, the alloys and their corrosion products caused no systematic or local cytotoxicological effects. Using microtomography and in vitro experiments, we could show that the magnesium-rare earth element alloys showed low corrosion rates, both in in vitro and in vivo. The lanthanum- and cerium-containing alloys degraded at comparable rates, whereas the neodymium-containing alloy showed the lowest corrosion rates.
authors.affiliation: Laboratory for Biomechanics and Biomaterials, Department of Orthopaedic Surgery, Hannover Medical School, Anna-von-Borries-Straße 1-7, 30625 Hannover, Germany; CrossBIT, Center for Biocompatibility and Implant-Immunology, Department of Orthopaedic Surgery, Hannover Medical School, Feodor-Lynen-Straße 31, 30625 Hannover, Germany.
authors.forename: Elmar
authors.initials: E
authors.lastname: Willbold
authors.affiliation: Department of Materials Science and Engineering, College of Engineering, Peking University, No. 5 Yi-He-Yuan Road, Hai-Dian District, Beijing 100871, China; Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China.
authors.forename: Xuenan
authors.initials: X
authors.lastname: Gu
authors.affiliation: Laboratory for Biomechanics and Biomaterials, Department of Orthopaedic Surgery, Hannover Medical School, Anna-von-Borries-Straße 1-7, 30625 Hannover, Germany; CrossBIT, Center for Biocompatibility and Implant-Immunology, Department of Orthopaedic Surgery, Hannover Medical School, Feodor-Lynen-Straße 31, 30625 Hannover, Germany; Swanson School of Engineering, Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Devon
authors.initials: D
authors.lastname: Albert
authors.affiliation: Laboratory for Biomechanics and Biomaterials, Department of Orthopaedic Surgery, Hannover Medical School, Anna-von-Borries-Straße 1-7, 30625 Hannover, Germany; CrossBIT, Center for Biocompatibility and Implant-Immunology, Department of Orthopaedic Surgery, Hannover Medical School, Feodor-Lynen-Straße 31, 30625 Hannover, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Kalla
authors.affiliation: Laboratory for Biomechanics and Biomaterials, Department of Orthopaedic Surgery, Hannover Medical School, Anna-von-Borries-Straße 1-7, 30625 Hannover, Germany; CrossBIT, Center for Biocompatibility and Implant-Immunology, Department of Orthopaedic Surgery, Hannover Medical School, Feodor-Lynen-Straße 31, 30625 Hannover, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Bobe
authors.affiliation: Laboratory for Biomechanics and Biomaterials, Department of Orthopaedic Surgery, Hannover Medical School, Anna-von-Borries-Straße 1-7, 30625 Hannover, Germany; CrossBIT, Center for Biocompatibility and Implant-Immunology, Department of Orthopaedic Surgery, Hannover Medical School, Feodor-Lynen-Straße 31, 30625 Hannover, Germany.
authors.forename: Maria
authors.initials: M
authors.lastname: Brauneis
authors.affiliation: Laboratory for Biomechanics and Biomaterials, Department of Orthopaedic Surgery, Hannover Medical School, Anna-von-Borries-Straße 1-7, 30625 Hannover, Germany; CrossBIT, Center for Biocompatibility and Implant-Immunology, Department of Orthopaedic Surgery, Hannover Medical School, Feodor-Lynen-Straße 31, 30625 Hannover, Germany.
authors.forename: Carla
authors.initials: C
authors.lastname: Janning
authors.affiliation: Institute of Materials Engineering, Technische Universität Dortmund, Leonhard-Euler-Straße 2, 44227 Dortmund, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Nellesen
authors.affiliation: Institute of Materials Engineering, Technische Universität Dortmund, Leonhard-Euler-Straße 2, 44227 Dortmund, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Czayka
authors.affiliation: Institute of Materials Engineering, Technische Universität Dortmund, Leonhard-Euler-Straße 2, 44227 Dortmund, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Tillmann
authors.affiliation: Department of Materials Science and Engineering, College of Engineering, Peking University, No. 5 Yi-He-Yuan Road, Hai-Dian District, Beijing 100871, China. Electronic address: yfzheng@pku.edu.cn.
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Laboratory for Biomechanics and Biomaterials, Department of Orthopaedic Surgery, Hannover Medical School, Anna-von-Borries-Straße 1-7, 30625 Hannover, Germany; CrossBIT, Center for Biocompatibility and Implant-Immunology, Department of Orthopaedic Surgery, Hannover Medical School, Feodor-Lynen-Straße 31, 30625 Hannover, Germany. Electronic address: frank.witte@charite.de.
authors.forename: Frank
authors.initials: F
authors.lastname: Witte
mesh_terms: D020341:Absorbable Implants; D000497:Alloys / Q000737:chemistry / Q000494:pharmacology; D000818:Animals; D041702:BALB 3T3 Cells; D001672:Biocompatible Materials / Q000138:chemical synthesis* / Q000494:pharmacology; D001826:Body Fluids / Q000737:chemistry*; D002470:Cell Survival / Q000187:drug effects*; D003343:Corrosion; D008274:Magnesium / Q000737:chemistry* / Q000494:pharmacology*; D008422:Materials Testing; D008674:Metals, Rare Earth / Q000737:chemistry* / Q000494:pharmacology; D051379:Mice; D011817:Rabbits; D013499:Surface Properties
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; D008674:Metals, Rare Earth; D008274:Magnesium
keywords: Biocompatibility; Biodegradable implants; In vitro; Magnesium alloy; Rare earth elements