Microstructure, in vitro corrosion behavior and cytotoxicity of biodegradable Mg-Ca-Zn and Mg-Ca-Zn-Bi alloys

• Main Authors: Bakhsheshi-Rad, H. R., Hamzah, E., Tok, H. Y., Kasiri-Asgarani, M., Jabbarzare, S., Medraj, M.
• Format: Article
• Published: Springer New York LLC 2017
• Subjects: TJ Mechanical engineering and machinery
• Online Access: http://eprints.utm.my/id/eprint/76469/; https://www.scopus.com/inward/record.uri?eid=2-s2.0-85008692965&doi=10.1007%2fs11665-016-2499-0&partnerID=40&md5=2ff5ad8a01ebc852f70757d5d2470048

The effects of bismuth (Bi) addition on the microstructure and corrosion behavior of the Mg-Ca-Zn-Bi alloys were evaluated using electron microscopy, electrochemical test and electrochemical impedance spectroscopy. Microstructural observations showed that Mg-1.2Ca-1Zn-xBi (x = 0.5, 1.5, 3 wt.%) are composed of Mg2Ca, Ca2Mg6Zn3 and Mg3Bi2 phases while a new phase Mg2Bi2Ca appeared after the addition of 5 and 12 wt.% Bi to the Mg-1.2Ca-1Zn alloy. Furthermore, the additions of 0.5 wt.% Bi to the Mg-1.2Ca-1Zn alloy slightly improved the corrosion behavior of the alloy, while further increase in Bi amount from 1.5 to 12 wt.% has a deleterious effect on the corrosion behavior of the ternary Mg-1.2Ca-1Zn alloy which is driven by galvanic coupling effect. Cytotoxicity tests indicate that the Mg-1.2Ca-1Zn presents higher cell viability compared to Mg-1.2Ca-1Zn-0.5Bi alloy. In addition, the cell viability of both alloys increased with increasing incubation time while diluting the extracts to 50% and 10% improved the cell viabilities. The present results suggest that the Mg-1.2Ca-1Zn-0.5Bi can be interesting candidate for the development of degradable biomaterials and it is worthwhile for further investigation in an in vivo environment.