Combinatorial Development and In Vitro Characterization of the Quaternary Zr–Ti–X–Y (X–Y = Cu–Ag/Co–Ni) Metallic Glass for Prospective Bioimplants

The prospect of Zr-based metallic glasses (MGs) in achieving a combination of properties, such as excellent electrochemical properties and extended biocompatibility, has been studied in this work. The combinatorial method (magnetron co-sputtering) has been adopted to fabricate two novel quaternary MG systems (Zr₅₀Ti₃₂Cu₁₃Ag₅ and Zr₄₀Ti₃₇Co₁₂Ni₁₁) with optimized compositions. The structural analysis has been performed by the grazing incidence x-ray diffraction and high-resolution transmission electron microscopy to affirm the disordered structure of the MG systems. The electrochemical analysis demonstrates lower corrosion- (0.10 and 0.04 μA cm⁻²), and passive (2.93 and 1.88 μA cm⁻²) current densities of the MGs. In addition, the MGs are found to have higher charge transfer resistance (4.70 and 7.86 MΩ cm²) compared to the 316L stainless steel (SS) (0.15 MΩ cm²) and cp-Ti (0.53 MΩ cm²). The electrochemical features are indicative towards higher corrosion-resistance capabilities of Zr₅₀Ti₃₂Cu₁₃Ag₅ and Zr₄₀Ti₃₇Co₁₂Ni₁₁ MGs to prevent adverse biological reactions. Additionally, the cell proliferation analysis manifests higher cell proliferation on the Zr₅₀Ti₃₂Cu₁₃Ag₅ and Zr₄₀Ti₃₇Co₁₂Ni₁₁ MGs for the MC3T3-E1 preosteoblast cells. Besides, the MTS assay analysis strengthens the prediction of cytocompatibility of the MGs. The integration of such unique properties makes these MG systems ideal candidates for biomedical implants.