Cellular and molecular interactions between MC3T3-E1 pre-osteoblasts and nanostructured titanium produced by high-pressure torsion.

Ultra-fine surface features are commonly used to modulate cellular activity on a variety of materials. The continuing challenge for materials in contact with bone is the development of a material with both favorable surface and bulk properties to modulate not only the cell-substrate interactions, but also to ensure the long-term stability of the implant. In a combined approach involving material sciences and cell and molecular biology, the nature and mechanism of cell-substrate interaction, in particular, the molecular machinery controlling cell response to the surface of the nanostructured titanium based material produced by the high pressure torsion (HPT) process is assessed. The degree of pre-osteoblast attachment and rate of growth, which are regulated through the activity and interaction of proteins present in the extracellular matrix and associated with cytoskeleton and focal adhesion, are notably increased on the HPT-processed titanium substrates. The improved cell activity is attributed to the nanostructured feature of these substrates consisting of ultra-fine crystals (<50 nm) and a distinct surface oxide layer which provide higher degree of surface wettability. These findings demonstrate the advantages of HPT-processed titanium over the conventional and coated titanium implants, as both mechanical properties and cellular response are improved.