The surface topology and composition of prosthetic implant materials affect cell responses and are therefore important design features. Plasma electrolytic oxidation (PEO) is a surface modification technique that can be used to produce oxidized surfaces with various surface properties. In this work, Ti-6Al-4V was PEO processed to give two surfaces with different morphologies but similar chemical composition. Surface characteristics were assessed using X ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, stylus profilometry and contact angle measurement.

In vitro culture of human foetal osteoblasts (HOB) was performed on the surfaces, to examine cell responses to them. Cellular proliferation, morphology and differentiation were examined, using the AlamarBlue assay, SEM imaging and an alkaline phosphatase (ALP) activity assay respectively. Additionally, the individual effects of oxides present in the PEO processed surfaces (rutile and anatase) on the cells were examined, by binding them in powder form to produce surfaces with similar morphology, but different composition.

Changes in the topology and chemistry of the surfaces affected osteoblast response. HOB proliferated more on the rougher PEO surface, and also displayed greater ALP activity. Also, cells responded differently to surfaces containing just rutile or anatase, indicating that the chemical phase of titanium oxide is of consequence for implant design.