Effect of electrochemical structuring of Ti6Al4V on osteoblast behaviour in vitro

Topography and surface chemistry have a profound effect on the way in which cells interact with an implant, which in turn impacts on clinical use and performance. In this paper we examine an electrochemical polishing approach in H₂SO₄/methanol that can be applied to the widely used orthopaedic/dentistry implant material, Ti6Al4V, to produce structured surfaces. The surface roughness, as characterized by R_a, was found to be dependent on the time of electropolishing but not on the voltage parameters used here. The surface chemistry, however, was dependent on the applied electrochemical potential. It was found that the chemical composition of the surface layer was modified during the electrochemical process, and at high potentials (9.0 V) a pure TiO₂ layer of at least 10 nm was created on top of the bulk alloy. Characterization of these surfaces with rat cells from the osteoblast lineage provided further evidence of contact guidance by microscale topography with morphology analysis correlating with surface roughness (R_a 300-550 nm). Formation of a bone-like matrix after long-term culture on these surfaces was not strongly dependent upon R _a values but followed the voltage parameter. These findings suggest that the surfaces created by treatment at higher voltages (9.0 V) produced a nanoscale layer of pure TiO₂ on the Ti6Al4V surface that influenced the programme of cellular differentiation culminating in osteogenesis.