Regulating the osteogenic function of rhBMP 2 by different titanium surface properties.

Bone morphogenetic protein 2 (BMP-2) is important for regulating the osteogenic differentiation of mesenchymal stem cells and the response of bone tissue. It adsorbs on the surface of biomedical implants immediately and plays a role of mediator between the materials surfaces and the host cells. Studies usually connect the material surface properties and the new bone formation directly. However, interaction between the adsorbed BMP-2 on the implant surface and the cells in the tissue is the key to explaining the osteogenic properties of the material. So, in this article, we investigated the conformational and functional changes induced by the surface modified titanium metals. We found that the α-helix and β-sheet structure of rhBMP-2 can be well maintained on the anodic oxidation treated titanium surface. The osteogenic function of rhBMP-2 can sustain for a relatively long time even though there is less amount adhere to the surface compared with that on the acid alkali treated titanium. Surface properties, especially the morphology enable a larger amount of rhBMP-2 to adsorb to the surface of the acid alkali treated titanium, but the conformation of the protein is severely influenced. The percentage of α-helix structure is also significantly decreased so that the efficacy of rhBMP-2 is only maintained in the early time. This study indicated that different surface modification of the surface could regulate the structure of rhBMP-2 and then further influence its osteogenic function. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1882-1893, 2016.