Corrosion resistance and biocompatibility of Ni-free Zr-based bulk metallic glass for biomedical applications

Aim: Currently, the potential applications of Ni-free bulk metallic glasses (BMGs) in biomedical fields that have been reported in the literature are still limited. In this study, the corrosion resistance and biocompatibility of Ni-free, Zr-based Zr ₅₀Cu ₄₃Al ₇ BMGs in biological environments were investigated. Methods: The corrosion resistance was evaluated using potentiodynamic polarization curve measurements in simulated biological environments. The cytotoxicity was evaluated according to specification 10993-5 from the International Organization for Standardization (ISO). The protein (albumin) adsorption was evaluated using the bicinchoninic acid (BCA) assay. The adhesion and in situ migration of human bone marrow mesenchymal stem cells (hMSCs) were also evaluated. Results: The main component on the outermost surface of Zr ₅₀Cu ₄₃Al ₇ BMG was ZrO ₂, with trace amounts of Cu and Al oxides. The corrosion rates of Zr ₅₀Cu ₄₃Al ₇ in artificial saliva and in simulated body fluid were comparable with those of biomedical Ti metal in the same environments; however, pitting corrosion was observed on Zr ₅₀Cu ₄₃Al ₇ in both environments. The cytotoxicity analysis results showed that Zr ₅₀Cu ₄₃Al ₇ was nontoxic. Compared with Ti metal, Zr ₅₀Cu ₄₃Al ₇ had a higher level of protein adsorption and better cell adhesion and cell migration. Conclusion: Zr ₅₀Cu ₄₃Al ₇ BMG has the potential to be used in biomedical applications because of its corrosion resistance and cellular responses. However, further improvements to the pitting corrosion resistance of Zr ₅₀Cu ₄₃Al ₇ in biological environments should be made before proceeding to in vivo animal studies. © 2012 Elsevier Ltd.