Towards understanding osteoblast responses to varied topographies of ultrastiff diamond surfaces

In this study, the impact of ultrastiff diamond surface topographies on osteoblast (bone forming cells, OB) responses (proliferation, spreading and filopodia extension) was studied using both experimental and modeling approaches. Ultrastiff diamond films with varied grain sizes (from less than 100 nm to approximately 600 nm) but similar surface chemistry and wettability were fabricated. Surface topography of the diamond changed dramatically as grain size grew. Experimental results demonstrated that OB proliferation and spreading on diamond surfaces were dependent on topography with the nanoscale topography exhibiting better OB proliferation and spreading than the micron topography. To explain this enhancement, OB filopodia extensions on varied diamond topographies were compared by using a dynamic model of filopodia extension responding to different topographies. Cell spreading and modeling results revealed that surface topography of diamond played a crucial role in governing OB responses.