Design of an implant surface with appropriate nanostructures has been considered to be an effective way to promote osteoblast cell growth and osseointegration. In this work, TiO2 nanorods were integrated into TiO2 nanodot films by hydrothermal growth to engineer a nanostructured surface composed of two nano-structural elements. The surface microstructure of the films depended on the integration degree. Low integration led to a surface nanostructure with exposure of the two nano-structural elements, and high integration resulted in a similar surface to a nanorod film. The nanorod integration had an obvious influence on pre-osteoblast cell responses and accelerated the cellular osteogenesis. Two factors of the integrated nano-structural element and the changed surface topology are believed to be responsible for enhancing cellular responses. The former is considered to play a more significant role because the nanorods tended to adsorb human fibronectin preferentially so as to begin differentiation to osteogenesis earlier. We anticipate this work may assist to gain insight into understanding of the interactions between nanostructured surfaces with cells.
