Electrochemical and surface characterization of anodized and fs-laser treated Ti6Al4V for osseo-repellent bone screws and dental implants

The surfaces of titanium grade 5 (Ti6Al4V) samples were altered on a micro and nano scale by femtosecond laser irradiation and subsequent electrochemical anodization. The produced micro-cones and nano-ripples covered by the additional oxide layer were characterised and their influence on osteoblast-like Saos-2 cell growth was studied. Surface topography and morphology were studied by Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). From the wettability experiments, it was found that the contact angle vs. roughness follows the Wenzel equation and that the wettability increases after the anodization. The composition of the formed oxide layer was determined by X-ray photoelectron spectroscopy (XPS) and oxide incorporation of phosphate ions could be confirmed. Moreover, estimated electrochemical surface area (ECSA) of the femtosecond laser treated sample was 14 times larger compared to a polished sample. The anodic oxide film formation factors for different electrolytes were determined and were in the range of 1.3 nm V−1-2.0 nm V−1. Finally, the samples anodized with 0.1 M H2SO4 and 3 M H3PO4 showed decreased Saos-2 cell growth.