title: Comparison of candidate materials for a synthetic osteo-odonto keratoprosthesis device.
abstract: OBJECTIVE
  Osteo-odonto keratoprosthesis is one of the most successful forms of keratoprosthesis surgery for end-stage corneal and ocular surface disease. There is a lack of detailed comparison studies on the biocompatibilities of different materials used in keratoprosthesis. The aim of this investigation was to compare synthetic bioinert materials used for keratoprosthesis surgery with hydroxyapatite (HA) as a reference.
  
  
  METHODS
  Test materials were sintered titanium oxide (TiO(2)), aluminum oxide (Al(2)O(3)), and yttria-stabilized zirconia (YSZ) with density >95%. Bacterial adhesion on the substrates was evaluated using scanning electron microscopy and the spread plate method. Surface properties of the implant discs were scanned using optical microscopy. Human keratocyte attachment and proliferation rates were assessed by cell counting and MTT assay at different time points. Morphologic analysis and immunoblotting were used to evaluate focal adhesion formation, whereas cell adhesion force was measured with a multimode atomic force microscope.
  
  
  RESULTS
  The authors found that bacterial adhesion on the TiO(2), Al(2)O(3), and YSZ surfaces were lower than that on HA substrates. TiO(2) significantly promoted keratocyte proliferation and viability compared with HA, Al(2)O(3,) and YSZ. Immunofluorescent imaging analyses, immunoblotting, and atomic force microscope measurement revealed that TiO(2) surfaces enhanced cell spreading and cell adhesion compared with HA and Al(2)O(3).
  
  
  CONCLUSIONS
  TiO(2) is the most suitable replacement candidate for use as skirt material because it enhanced cell functions and reduced bacterial adhesion. This would, in turn, enhance tissue integration and reduce device failure rates during keratoprosthesis surgery.
authors.affiliation: Singapore Eye Research Institute, Singapore.
authors.forename: Xiao Wei
authors.initials: XW
authors.lastname: Tan
authors.forename: A Promoda P
authors.initials: AP
authors.lastname: Perera
authors.forename: Anna
authors.initials: A
authors.lastname: Tan
authors.forename: Donald
authors.initials: D
authors.lastname: Tan
authors.forename: K A
authors.initials: KA
authors.lastname: Khor
authors.forename: Roger W
authors.initials: RW
authors.lastname: Beuerman
authors.forename: Jodhbir S
authors.initials: JS
authors.lastname: Mehta
mesh_terms: D000537:Aluminum Oxide / Q000378:metabolism; D000539:Alveolar Process / Q000637:transplantation; D001422:Bacterial Adhesion / Q000502:physiology*; D001672:Biocompatible Materials / Q000378:metabolism*; D015153:Blotting, Western; D002448:Cell Adhesion / Q000502:physiology*; D049109:Cell Proliferation; D002470:Cell Survival; D002478:Cells, Cultured; D003316:Corneal Diseases / Q000601:surgery; D003319:Corneal Stroma / Q000166:cytology; D003481:Cuspid / Q000637:transplantation; D003598:Cytoskeletal Proteins / Q000378:metabolism; D017886:Durapatite / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism*; D006801:Humans; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D019736:Prostheses and Implants; D013211:Staphylococcus aureus / Q000502:physiology / Q000648:ultrastructure; D014025:Titanium / Q000378:metabolism; D015019:Yttrium / Q000378:metabolism; D015040:Zirconium / Q000378:metabolism
chemical_list: D001672:Biocompatible Materials; D003598:Cytoskeletal Proteins; C499362:yttria stabilized tetragonal zirconia; C009495:titanium dioxide; D015019:Yttrium; D017886:Durapatite; D015040:Zirconium; D014025:Titanium; D000537:Aluminum Oxide