In vitro degradation and mineralization of high-purity magnesium in three physiological fluids

Abstract High-purity magnesium (HP-Mg) was studied as a candidate biodegradable material for biliary and urinary stents. Electrochemical measurements and immersion tests were conducted to compare the in vitro degradation behavior of HP-Mg in modified simulated body fluid (m-SBF), artificial urine and human bile. We showed that HP-Mg corroded more uniformly and much slower in bile than in m-SBF and artificial urine, slower corrosion rate resulting in a small amount of corrosion products which are mainly amorphous probably will not cause problem such as biliary occlusion, suggesting Mg and its alloys may be a potential material for biliary stents. In terms of corrosion products, crystalized minerals such as Mg 2 CO 3 (OH) 2 ·3H 2 O, CaHPO 4 ·2H 2 O and hydroxyapatite which may be the precursors of ureteral stones were deposited on HP-Mg after immersion in artificial urine, but not in bile or m-SBF, which suggested a potential risk of urolithiasis when using the bared HP-Mg as a urinary stent.