Alloy Design and Biocompatibility Evaluation of Low Modulus Titanium Alloys

摘要

Alloy design and in-vitro assessment of biocompatibilities of novel titanium alloys with low elastic modulus were studied. A contour map of elastic modulus which enables to predict low modulus alloy composition was established by using electron theory. Ti-30Ta-10Nb-10Zr, Ti-40Ta-10Nb-10Zr and Ti-40Ta-10Nb-4Sn alloys were designed by using the contour map of elastic modulus, and Young's moduli of those alloys were as low as around 60 GPa. Anodic polarization curves for the alloys represented that corrosion resistance of Ti-40Ta-10Nb-10Zr and Ti-40Ta-10Nb-10Zr was comparable to those of biomedically approved CP Ti and Ti-6A1-4V in simulated body fluid(Hank's solution) at 37 deg C, while corrosion resistance of Ti-40Ta-10Nb-4Sn was inferior to those of CP Ti and Ti-6A1-4V. MTT assay with osteoblast-like cells(MG63) showed that the extent of initial cell attachment was similar in all alloys, while cell proliferation of Ti-40Ta-10Nb-lOZr and Ti-40Ta-10Nb-4Sn alloys was more sluggish than those in CP Ti and Ti-6A1-4V. It was therefore realized that the selection of alloying elements for designing low modulus alloys should be considered in the viewpoint of cell growth as well as cytotoxicity.