Effect of a niobium-containing titanium alloy on osteoblast behavior in culture

Background: The chemistry of titanium is a key factor in determining implant-tissue interactions. Reports that a vanadium-based titanium alloy (Ti-6Al-4V) exhibits some cytotoxicity led to a search for an alternative. Aim: The aim of the present study was to investigate the behavior of human osteoblast-like cells (Saos-2) cultured on Ti-6Al-4V or Ti-6Al-7Nb disks with a rough or a machined surface. Results: In all four groups, the cells proliferated rapidly between days 1 and 3, and then plateaued. On day 1 of culture, the highest proliferation rate was of cells cultured on disks containing Nb with a machined surface. On day 7, there was no significant difference in cell density on all the tested surfaces. Alkaline phosphatase (ALP) activity was lower on the machined surfaces, regardless of the material used, suggesting that cells on rough surfaces exhibit a more mature phenotype. On day 3, cells cultured on rough disks made of Ti-6Al-7Nb showed the highest ALP activity; the lowest activity was observed on the machined Ti-6Al-4V surface. The highest level of osteocalcin (day 7) was found in the cells cultured on rough Ti-6Al-7Nb disks. Also, higher levels of transforming growth factor (TGFβ) were noted for cells cultured on the rough Ti-6Al-7Nb disks, suggesting that the Nb-containing alloy supports more rapid maturation of the osteoblast. Conclusions: The results of the present study suggest that according to our cell culture preclinical model, Ti-6Al-7Nb may replace the Ti-6Al-4V alloy as an implant material.