title: The effect of immobilization of heparin and bone morphogenic protein-2 (BMP-2) to titanium surfaces on inflammation and osteoblast function.
abstract: The aim of this study was to investigate biologic function of bone morphorgenic protein-2 (rhBMP-2) immobilized on the heparin-grafted Ti surface. Ti surfaces were first modified by 3-aminopropyltriethoxysilane (ATPES), followed by grafting of heparin. BMP-2 was then immobilized on the heparin-grafted Ti surfaces. Pristine Ti and functionalized Ti surfaces were characterized by X-ray photoelectron spectroscopy (XPS), measurement of water contact angles, and protein adsorption. The biological activity of MG-63 cells on pristine and functionalized Ti surfaces was investigated by cell proliferation assays, measurement of alkaline phosphate (ALP) activity, and determination of calcium deposition. Anti-inflammatory effects were assessed by RT-PCR to measure the transcript levels of IL-6 and TNF-α. XPS revealed that heparin and BMP-2 were successfully grafted and immobilized on the Ti surfaces, respectively. In addition, Ti surfaces with BMP-2 immobilized were more hydrophilic than pristine Ti. Furthermore, BMP-2 immobilized Ti promoted significantly higher ALP activity and calcium deposition by MG-63 cells than pristine Ti. The inflammatory response was also decreased when cells were grown on heparin-grafted, BMP-2-immobilized Ti surfaces. The results of this study suggest that by grafting heparin and immobilizing BMP-2 on Ti surfaces, inflammation can be inhibited and osteoblast function promoted.
authors.affiliation: Department of Orthopedic Surgery and Rare Diseases Institute, Korea University Medical College, Guro Hospital, Seoul, Korea.
authors.forename: Sung Eun
authors.initials: SE
authors.lastname: Kim
authors.forename: Sang-Hun
authors.initials: SH
authors.lastname: Song
authors.forename: Young Pil
authors.initials: YP
authors.lastname: Yun
authors.forename: Byung-Joon
authors.initials: BJ
authors.lastname: Choi
authors.forename: Il Keun
authors.initials: IK
authors.lastname: Kwon
authors.forename: Min Soo
authors.initials: MS
authors.lastname: Bae
authors.forename: Ho-Jin
authors.initials: HJ
authors.lastname: Moon
authors.forename: Yong-Dae
authors.initials: YD
authors.lastname: Kwon
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000737:chemistry / Q000276:immunology* / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D006493:Heparin / Q000737:chemistry / Q000276:immunology* / Q000494:pharmacology*; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D008855:Microscopy, Electron, Scanning; D041681:NIH 3T3 Cells; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D056951:Photoelectron Spectroscopy; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014025:Titanium / Q000737:chemistry*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
chemical_list: D055396:Bone Morphogenetic Protein 2; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D006493:Heparin; D014025:Titanium; D000469:Alkaline Phosphatase; D002118:Calcium