In vitro and in vivo comparison of binary Mg alloys and pure Mg

https://doi.org/10.1016/j.msec.2015.12.064Get rights and content
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Highlights

  • Viable pre-osteoblast cells verified for 13 days on the Mg alloys in in vitro conditions.

  • Degradation performance of pure Mg, Mg2Ag and Mg10Gd compared in in vitro and in vivo conditions.

  • Mg2Ag reveals a significant higher in vitro degradation rate after one week in comparison to the in vivo situation.

  • Degradation rates of the materials are comparable between in vitro and in vivo conditions after 4 weeks.

Abstract

Biodegradable materials are under investigation due to their promising properties for biomedical applications as implant material. In the present study, two binary magnesium (Mg) alloys (Mg2Ag and Mg10Gd) and pure Mg (99.99%) were used in order to compare the degradation performance of the materials in in vitro to in vivo conditions.

In vitro analysis of cell distribution and viability was performed on discs of pure Mg, Mg2Ag and Mg10Gd. The results verified viable pre-osteoblast cells on all three alloys and no obvious toxic effect within the first two weeks.

The degradation rates in in vitro and in vivo conditions (Sprague–Dawley® rats) showed that the degradation rates differ especially in the 1st week of the experiments. While in vitro Mg2Ag displayed the fastest degradation rate, in vivo, Mg10Gd revealed the highest degradation rate. After four weeks of in vitro immersion tests, the degradation rate of Mg2Ag was significantly reduced and approached the values of pure Mg and Mg10Gd. Interestingly, after 4 weeks the estimated in vitro degradation rates approximate in vivo values.

Our systematic experiment indicates that a correlation between in vitro and in vivo observations still has some limitations that have to be considered in order to perform representative in vitro experiments that display the in vivo situation.

Abbreviations

DR
degradation rate
DMEM
Dulbecco's Modified Eagle's Medium
μCT
micro-computed tomography
BN
boron-nitride
SEM
Scanning Electron Microscopy
BSE
back scattered electron
EDX
energy dispersive X-ray
FBS
fetal bovine serum
PBS
Phosphate Buffered Saline

Keywords

Magnesium alloys
Biodegradable implants
Degradation rate
in vitro
in vivo

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