Osteoblast Responses to Titanium-Coated Subcellular Scaled Microgrooves.

Statistical data have consistently shown that implant loosening is a significant causative factor for revision surgeries. Both in vivo and in vitro studies have confirmed the positive influences of microgrooved titanium implant surfaces on improving orthopedic titanium implants compared with a smooth titanium surface. Complete cell-groove adhesion is a prerequisite for rapid and robust osseointegration. For the first time, this work has quantified the influence of the titanium groove width at the subcellular scale (5-20 µm) on osteoblast responses, using titanium-coated microgrooved silicon wafer specimens (surface roughness, Ra = ∼1.5 nm), which can avoid the latent influence of variations in surface roughness from the use of normal titanium substrates. The cell-groove adhesion increased from 53.07% to 98.55% with an increasing groove width from 5 to 20 µm. In addition, both the cell spreading area and cell width were proportional to groove width. However, no statistically significant influence (p > 0.05) of groove width was identified on cell proliferation and differentiation. An exponential model was proposed to predict the groove geometries that can facilitate complete cell-groove adhesion. The underlying mechanisms were discussed. The experimental findings of this study provide a unique basis for the design of titanium implant surfaces.

The effect of ordered and partially ordered surface topography on bone cell responses: a review.

Implant surfaces play important roles in regulating protein adsorption and determining subsequent cell responses, including cell attachment, proliferation, migration and differentiation. With rapid developments in micro- and nano-fabrication methods and additive manufacturing (3D printing) technologies, precisely controlled patterns such as partially ordered or ordered patterns can now be generated on bone implant surfaces, rather than restricted to randomly roughened surfaces. Over the last two decades, much effort has been dedicated to manipulating cell responses through surface topographical modifications. This review discusses the recent developments and understanding of surface topography in prompting or enhancing desired cell responses, particularly the roles of ordered and partially ordered surface topography under in vitro conditions. In addition, the challenges to translate research findings into implant applications are addressed.