Biodegradable Mg corrosion and osteoblast cell culture studies

Magnesium (Mg) is a biodegradable metal that has significant potential advantages as an implant material. In this paper, corrosion and cell culture experiments were performed to evaluate the biocompatibility of Mg. The corrosion current and potential of a Mg disk were measured in different physiological solutions including deionized (DI) water, phosphate-buffered saline (PBS), and McCoy's 5A culture medium. The corrosion currents in the PBS and in the McCoy's 5A-5% FBS media were found to be higher than in DI water, which is expected because corrosion of Mg occurs faster in a chloride solution. Weight loss, open-circuit potential, and electrochemical impedance spectroscopy measurements were also performed. The Mg specimens were also characterized using an environmental scanning electron microscope and energy-dispersive X-ray analysis (EDAX). The X-ray analysis showed that in the cell culture media a passive interfacial layer containing oxygen, chloride, phosphate, and potassium formed on the samples. U2OS cells were then co-cultured with a Mg specimen for up to one week. Cytotoxicity results of magnesium using MTT assay and visual observation through cell staining were not significantly altered by the presence of the corroding Mg sample. Further, bone tissue formation study using von Kossa and alkaline phosphatase staining indicates that Mg may be suitable as a biodegradable implant material.