title: Submicron scale-structured hydrophilic titanium surfaces promote early osteogenic gene response for cell adhesion and cell differentiation.
abstract: OBJECTIVE
  Titanium (Ti) surface roughness and surface hydrophilicity are key factors to regulate osteogenic cell responses during dental implant healing. In detail, specific integrin-mediated interactions with the extracellular environment trigger relevant osteogenic cell responses like differentiation and matrix synthesis via transcriptions factors. Aim of this study was to monitor surface-dependent osteogenic cell adhesion dynamics, proliferation, and specific osteogenic cell differentiation over a period of 7 days.
  
  
  METHODS
  Ti disks were manufactured to present smooth pretreatment (PT) surfaces and rough sandblasted/acid-etched (SLA) surfaces. Further processing to isolate the uncontaminated TiO(2) surface from contact with atmosphere provided a highly hydrophilic surface without alteration of the surface topography (modSLA). Tissue culture polystyrene (TCPS) served as control. Human osteogenic cells were cultivated on the respective substrates. After 24 hours, 48 hours, 72 hours, and 7 days, cell morphology on the Ti substrates was visualized by scanning transmission electron microscopy. As a marker of cellular proliferation, cell count was assessed. For the analysis of cell adhesion and differentiation, specific gene expression levels of the integrin subunits β1 and αv, runx-2, collagen type Iα (COL), alkaline phosphatase (AP), and osteocalcin (OC) were obtained by real-time RT-PCR for the respective time points. Data were normalized to internal controls.
  
  
  RESULTS
  TCPS and PT surfaces preserved a rather immature, dividing osteogenic phenotype (high proliferation rates, low integrin levels, and low specific osteogenic cell differentiation). SLA and especially modSLA surfaces promoted both cell adhesion as well as the maturation of osteogenic precursors into post-mitotic osteoblasts. In detail, during the first 48 hours, modSLA resulted in lowest cell proliferation rates but exhibited highest levels of the investigated integrins, runx-2, COL, AP, and OC.
  
  
  CONCLUSIONS
  Our results revealed a strong synergistic effect between submicron-scale roughness and surface hydrophilicity on early osteogenic cell adhesion and maturation.
authors.affiliation: Oral and Maxillofacial Surgery, University Medicine Mainz, Mainz, Germany. klein@mkg.klinik.uni-mainz.de
authors.forename: Marcus Oliver
authors.initials: MO
authors.lastname: Klein
authors.forename: Ana
authors.initials: A
authors.lastname: Bijelic
authors.forename: Thomas
authors.initials: T
authors.lastname: Ziebart
authors.forename: Felix
authors.initials: F
authors.lastname: Koch
authors.forename: Peer W
authors.initials: PW
authors.lastname: Kämmerer
authors.forename: Marco
authors.initials: M
authors.lastname: Wieland
authors.forename: Moritz A
authors.initials: MA
authors.lastname: Konerding
authors.forename: Bilal
authors.initials: B
authors.lastname: Al-Nawas
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000469:Alkaline Phosphatase / Q000032:analysis; D002448:Cell Adhesion / Q000235:genetics; D002452:Cell Count; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000235:genetics; D049109:Cell Proliferation; D048430:Cell Shape; D002478:Cells, Cultured; D024042:Collagen Type I / Q000032:analysis; D050659:Core Binding Factor Alpha 1 Subunit / Q000032:analysis; D045662:Dental Etching / Q000379:methods; D003764:Dental Materials / Q000737:chemistry*; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D039564:Integrin alphaV / Q000032:analysis; D019012:Integrin beta1 / Q000032:analysis; D017348:Microscopy, Electron, Scanning Transmission; D010006:Osteoblasts / Q000502:physiology*; D015675:Osteocalcin / Q000032:analysis; D010012:Osteogenesis / Q000235:genetics*; D010641:Phenotype; D011137:Polystyrenes / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*
chemical_list: D024042:Collagen Type I; D050659:Core Binding Factor Alpha 1 Subunit; D003764:Dental Materials; D039564:Integrin alphaV; D019012:Integrin beta1; D011137:Polystyrenes; C493709:RUNX2 protein, human; D015675:Osteocalcin; C009495:titanium dioxide; D014025:Titanium; D000469:Alkaline Phosphatase