In-vitro corrosion and cytocompatibility assessment of compositionally complex β-Ti alloy for implant applications

Compositionally complex alloys (CCAs), also known as multi-principal element alloys, are gaining considerable attention in the biomedical field based upon their good durability, high corrosion resistance and potential biocompatibility. Two novel Ti-rich β-CCAs: Ti<inf>55</inf>–Zr<inf>25</inf>–Nb<inf>15</inf>–Fe<inf>4</inf>–Mo<inf>1</inf> (CCA-1) and Ti<inf>60</inf>–Zr<inf>20</inf>–Nb<inf>15</inf>–Fe<inf>2</inf>–Mo<inf>3</inf> (CCA-2) were fabricated in a vacuum arc melting furnace. In the present study, corrosion resistance of the as-cast CCAs was examined in simulated body fluid at 37 °C, replicating normal physiological conditions. The Ti–CCAs displayed comparable corrosion resistance to Ti–6Al–4V, while exhibiting lower corrosion current density (I<inf>corr</inf>) and increased polarization resistance. The as-cast Ti–6Al–4V sample used in the comparative study was also prepared under the same conditions as the CCAs. The study of biocompatibility for the CCAs was examined through immersion tests of the CCAs in Earle's balanced salt solution (EBSS) for a period of 21 days. After the immersion period, an XRD was carried out to detect any phase change in the CCAs. The surface of the immersed samples was examined after 7, 14 and 21 days through Field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy to detect the formation of any by-products. Cytocompatibility study by MTT assay using MG-63 cells for a period of 7 days confirmed that Ti–CCAs can support cell viability and proliferation. FESEM analysis revealed that the cells cultured on the CCA surfaces showed the characteristic morphology of osteoblasts. Owing to their good corrosion resistance and positive cellular response, the Ti–CCAs can be considered a potential candidate for biomedical implants. © 2025 Elsevier B.V.