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Magnesium alloys: Predicting in vivo corrosion with in vitro immersion testing
Author(s) -
Walker Jemimah,
Shadanbaz Shaylin,
Kirkland Nicholas T.,
Stace Edward,
Woodfield Tim,
Staiger Mark P.,
Dias George J.
Publication year - 2012
Publication title -
journal of biomedical materials research part b: applied biomaterials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.665
H-Index - 108
eISSN - 1552-4981
pISSN - 1552-4973
DOI - 10.1002/jbm.b.32680
Subject(s) - corrosion , in vivo , magnesium , in vitro , materials science , titanium , sodium bicarbonate , bovine serum albumin , nuclear chemistry , chemistry , biomedical engineering , metallurgy , chromatography , biochemistry , biology , organic chemistry , medicine , microbiology and biotechnology
Magnesium (Mg) and its alloys have been proposed as degradable replacements to commonly used orthopedic biomaterials such as titanium alloys and stainless steel. However, the corrosion of Mg in a physiological environment remains a difficult characteristic to accurately assess with in vitro methods. The aim of this study was to identify a simple in vitro immersion test that could provide corrosion rates similar to those observed in vivo . Pure Mg and five alloys (AZ31, Mg‐0.8Ca, Mg‐1Zn, Mg‐1Mn, Mg‐1.34Ca‐3Zn) were immersed in either Earle's balanced salt solution (EBSS), minimum essential medium (MEM), or MEM‐containing 40 g/L bovine serum albumin (MEMp) for 7, 14, or 21 days before removal and assessment of corrosion by weight loss. This in vitro data was compared to in vivo corrosion rates of the same materials implanted in a subcutaneous environment in Lewis rats for equivalent time points. The results suggested that, for the alloys investigated, the EBSS buffered with sodium bicarbonate provides a rate of degradation comparable to those observed in vivo. In contrast, the addition of components such as (4‐(2‐hydroxyethyl)‐1‐piperazineethanesulfonic acid) (HEPES), vitamins, amino acids, and albumin significantly increased corrosion rates. Based on these findings, it is proposed that with this in vitro protocol, immersion of Mg alloys in EBSS can be used as a predictor of in vivo corrosion. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.