Element distribution in the corrosion layer and cytotoxicity of alloy Mg-10Dy during in vitro biodegradation

The present work investigates the corrosion behaviour, the element distribution in the corrosion layer and the cytocompatibility of alloy Mg-10Dy. The corrosion experiments were performed in a cell culture medium (CCM) under cell culture conditions close to the in vivo environment. The element distribution on the surface as well as in cross-sections of the corrosion layer was investigated using scanning electron microscopy, energy-dispersive X-ray analysis, X-ray photoelectron spectroscopy and X-ray diffraction. The cytocompatibility of alloy Mg-10Dy with primary human osteoblasts was evaluated by MTT, cell adhesion and live/dead staining tests. The results show that the corrosion layer was enriched in Dy, while the P and Ca content gradually decreased from the surface to the bottom of the corrosion layer. In addition, large amounts of MgCO3·3H2O formed in the corrosion layer after 28 days immersion. Both extracts and the Dy-enriched corrosion layer of alloy Mg-10Dy showed no cytotoxicity to primary human osteoblasts.