Effects of controlled micro-/nanosurfaces on osteoblast proliferation

Micro-/nanostructured implant surfaces mimicking natural bone architecture are expected to have positive effects on osteoblast proliferation. In this study, to clarify the optimal microstructure scale on micro-/nano-titanium surfaces, highly controlled microstructure surfaces were fabricated with a titania nanotube oxide layer by sandblast treatment and electrochemical anodization. Average surface roughness (R_a ) and mean width of the profile elements (R_Sm ) increased in proportion to the size of the blasting media. The crystalline structure and wettability were similar for all samples after anodizing and annealing. MG63 osteoblast-like osteosarcoma cells showed reduced spreading area on smaller microstructure surfaces after incubation for 24 h. Cell proliferation assays, including cell counting and cell cycle analyses, showed that micro-/nanosurfaces with smaller microstructures (R_a  = 0.6 µm, R_Sm  = 11.1 µm) had the most positive effect. This result indicated that smaller microstructures of hierarchical surfaces enhanced cell proliferation, despite similar chemical compositions and wettabilities. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2589-2596, 2017.