title: A Strontium-Modified Titanium Surface Produced by a New Method and Its Biocompatibility In Vitro.
abstract: OBJECTIVE
  To present a new and effective method of producing titanium surfaces modified with strontium and to investigate the surface characteristics and in vitro biocompatibility of titanium (Ti) surfaces modified with strontium (Sr) for bone implant applications.
  
  
  METHODS
  Sr-modified Ti surfaces were produced by sequential treatments with NaOH, strontium acetate, heat and water. The surface characteristics and the concentration of the Sr ions released from the samples were examined. Cell adhesion, morphology and growth were investigated using osteoblasts isolated from the calvaria of neonatal Sprague-Dawley rats. Expression of osteogenesis-related genes and proteins was examined to assess the effect of the Sr-modified Ti surfaces on osteoblasts.
  
  
  RESULTS
  The modified titanium surface had a mesh structure with significantly greater porosity, and approximately5.37±0.35at.% of Sr was incorporated into the surface. The hydrophilicity was enhanced by the incorporation of Sr ions and water treatment. The average amounts of Sr released from the Sr-modified plates subjected to water treatment were slight higher than the plates without water treatment. Sr promoted cellular adhesion, spreading and growth compared with untreated Ti surfaces. The Sr-modified Ti plates also promoted expression of osteogenesis-related genes,and expression of OPN and COL-І by osteoblasts. Ti plates heat treated at 700°C showed increased bioactivity in comparison with those treated at 600°C. Water treatment upregulated the expression of osteogenesis-related genes.
  
  
  CONCLUSIONS
  These results show that Sr-modification of Ti surfaces may improve bioactivity in vitro. Water treatment has enhanced the response of osteoblasts. The Sr-modified Ti heat-treated at 700°C exhibited better bioactivity compared with that heated at 600°C.
authors.affiliation: Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, P. R. China; College of Stomatology, Southern Medical University, Guangzhou, P. R. China.
authors.forename: Chundong
authors.initials: C
authors.lastname: Liu
authors.affiliation: Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, P. R. China; College of Stomatology, Southern Medical University, Guangzhou, P. R. China.
authors.forename: Yanli
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, P. R. China; College of Stomatology, Southern Medical University, Guangzhou, P. R. China.
authors.forename: Lichao
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Stomatology, the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, P. R. China.
authors.forename: Xinhua
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, P. R. China; College of Stomatology, Southern Medical University, Guangzhou, P. R. China.
authors.forename: Qiuyue
authors.initials: Q
authors.lastname: Chen
authors.affiliation: Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, P. R. China; College of Stomatology, Southern Medical University, Guangzhou, P. R. China.
authors.forename: Buling
authors.initials: B
authors.lastname: Wu
mesh_terms: D000085:Acetates / Q000737:chemistry*; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry* / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects; D024042:Collagen Type I / Q000235:genetics / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects; D053495:Osteopontin / Q000235:genetics / Q000378:metabolism; D016062:Porosity; D051381:Rats; D017207:Rats, Sprague-Dawley; D013324:Strontium / Q000737:chemistry*; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*
chemical_list: D000085:Acetates; D001672:Biocompatible Materials; D024042:Collagen Type I; D053495:Osteopontin; C106741:strontium acetate; D014025:Titanium; D013324:Strontium