title: Magnesium degradation influenced by buffering salts in concentrations typical of in vitro and in vivo models.
abstract: Magnesium and its alloys have considerable potential for orthopedic applications. During the degradation process the interface between material and tissue is continuously changing. Moreover, too fast or uncontrolled degradation is detrimental for the outcome in vivo. Therefore in vitro setups utilizing physiological conditions are promising for the material/degradation analysis prior to animal experiments. The aim of this study is to elucidate the influence of inorganic salts contributing to the blood buffering capacity on degradation. Extruded pure magnesium samples were immersed under cell culture conditions for 3 and 10 days. Hank's balanced salt solution without calcium and magnesium (HBSS) plus 10% of fetal bovine serum (FBS) was used as the basic immersion medium. Additionally, different inorganic salts were added with respect to concentration in Dulbecco's modified Eagle's medium (DMEM, in vitro model) and human plasma (in vivo model) to form 12 different immersion media. Influences on the surrounding environment were observed by measuring pH and osmolality. The degradation interface was analyzed by electron-induced X-ray emission (EIXE) spectroscopy, including chemical-element mappings and electron microprobe analysis, as well as Fourier transform infrared reflection micro-spectroscopy (FTIR).
authors.affiliation: Helmholtz-Zentrum Geesthacht, Institute of Material Research, Division of Metallic Biomaterials, Max-Planck-Str. 1, 21502 Geesthacht.
authors.forename: Nezha Ahmad
authors.initials: NA
authors.lastname: Agha
authors.affiliation: Helmholtz-Zentrum Geesthacht, Institute of Material Research, Division of Metallic Biomaterials, Max-Planck-Str. 1, 21502 Geesthacht.
authors.forename: Frank
authors.initials: F
authors.lastname: Feyerabend
authors.affiliation: University of Hamburg, Department of Earth Sciences, Grindelallee 48, 20146 Hamburg, Germany.
authors.forename: Boriana
authors.initials: B
authors.lastname: Mihailova
authors.affiliation: University of Hamburg, Department of Earth Sciences, Grindelallee 48, 20146 Hamburg, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Heidrich
authors.affiliation: University of Hamburg, Department of Earth Sciences, Grindelallee 48, 20146 Hamburg, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Bismayer
authors.affiliation: Helmholtz-Zentrum Geesthacht, Institute of Material Research, Division of Metallic Biomaterials, Max-Planck-Str. 1, 21502 Geesthacht.
authors.forename: Regine
authors.initials: R
authors.lastname: Willumeit-Römer
mesh_terms: D002021:Buffers; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000737:chemistry*; D013058:Mass Spectrometry; D009994:Osmolar Concentration; D012492:Salts / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D002021:Buffers; D012492:Salts; D008274:Magnesium
keywords: Biomaterial; Degradation; EIXE; Infrared spectroscopy; Inorganic salts; Magnesium