title: The Characterization and Osteogenic Activity of Nanostructured Strontium-Containing Oxide Layers on Titanium Surfaces.
abstract: OBJECTIVE
  The aim of this study was to compare strontium-containing implant (Sr-Ti) surfaces with modified pure Ti (Mod Ti) on the promotion of osteogenesis in vitro and in vivo.
  
  
  METHODS
  The Sr-Ti surfaces were fabricated by hydrothermal treatment. The Mod Ti surfaces were used as a control. These surfaces were characterized with scanning electron microscopy, x-ray diffractometer, and x-ray photoelectron spectroscopy. The biologic activity was analyzed by initial adhesion, proliferation, alkaline phosphatase (ALP), osteocalcin, and osteogenesis-related genes in vitro. Hematoxylin and eosin (H&E) staining and immunohistochemistry analysis of tissue adjacent to this implant were used to evaluate osteogenic activity in vivo.
  
  
  RESULTS
  The results confirmed multiple nanogranules on the Sr-Ti surface composed of well-crystallized TiO₂ and SrTiO₃ phases. Long-term release of Sr enhanced mesenchymal stem cell (MSC) initial adhesion, the production of ALP, osteocalcin, and upregulated osteogenesis-related genes. For in vivo osteogenic evaluation, mesenchymal-like cells were adhered on these two surfaces under the electron microscope and transitory hematoma in adjacent bone tissue by H&E staining. The Stro-1-labeled MSCs were noted around the Sr-Ti surface in immunohistochemistry analysis.
  
  
  CONCLUSIONS
  This study suggests that Sr-Ti surfaces with nanostructures could promote the response of MSCs in vitro, and recruit Stro-1 labeled MSCs in vivo.
authors.forename: Yun
authors.initials: Y
authors.lastname: Chen
authors.forename: Xiao-Yi
authors.initials: XY
authors.lastname: Chen
authors.forename: Jian-Wei
authors.initials: JW
authors.lastname: Shen
authors.forename: Fu-Ming
authors.initials: FM
authors.lastname: He
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D015415:Biomarkers / Q000378:metabolism; D001842:Bone and Bones / Q000378:metabolism; D002448:Cell Adhesion / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology; D049109:Cell Proliferation / Q000502:physiology; D006801:Humans; D020007:Implants, Experimental; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D023421:Models, Animal; D049329:Nanostructures / Q000737:chemistry; D010006:Osteoblasts / Q000166:cytology; D015675:Osteocalcin / Q000378:metabolism; D010012:Osteogenesis / Q000502:physiology*; D010087:Oxides; D056951:Photoelectron Spectroscopy; D051381:Rats; D017207:Rats, Sprague-Dawley; D013324:Strontium / Q000737:chemistry*; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D015415:Biomarkers; D010087:Oxides; D015675:Osteocalcin; D014025:Titanium; D000469:Alkaline Phosphatase; C119252:strontium titanium oxide; D013324:Strontium