title: Photocoupling of fibronectin to titanium surfaces influences keratinocyte adhesion, pellicle formation and thrombogenicity.
abstract: OBJECTIVE
  Coating of implant surfaces with biomolecules can influence basic host responses and enhance subsequent tissue integration. The biological factors have to be immobilized on the implant material. Human fibronectin (Fn) was used as a model protein and covalently coupled to titanium (Ti) surfaces via silanization and an anthraquinone linker. The impact on several aspects of initial host/biomaterial interactions (keratinocyte adhesion, platelet interactions and pellicle formation) was studied.
  
  
  METHODS
  Coupling efficiency was characterized by immunological techniques. The effects of coupled Fn on initial host/biomaterial interactions were assessed. Cell adhesion and spreading were investigated by fluorescent staining, pellicle formation by an acoustic sensor system (quartz crystal microbalance with dissipation, QCM-D), and platelet adhesion as one parameter mediating the inflammatory response by scanning electron microscopy (SEM) and immunological assays.
  
  
  RESULTS
  Coupling efficiency was related to irradiation time used for photochemical coupling of the UV-activated anthraquinone to the silanized Ti surface. With an optimized protocol, the amount of Fn coupled to the surface could be almost doubled compared to standard dip-coating methods. On the anthraquinone-coupled Fn coatings, cell adhesion and spreading of human keratinocytes was significantly enhanced. Online detection of pellicle formation revealed strong reversibility of saliva protein adhesion on Fn coated surfaces compared to the pure Ti surface. Furthermore, the Fn coated Ti showed a low thrombogenicity.
  
  
  CONCLUSIONS
  This study suggests that anthraquinone-coupled biological coatings may be useful for biofunctionalization of Ti dental implants by enhancement of soft tissue re-integration (restoration of the epithelial seal) combined with diminished pellicle formation.
authors.affiliation: Department of Prosthodontics, Section Medical Materials and Technology, Center for Dental, Oral and Maxillofacial Medicine, University of Tübingen, Germany. lutz.scheideler@med.uni-tuebingen.de
authors.forename: Lutz
authors.initials: L
authors.lastname: Scheideler
authors.forename: Frank
authors.initials: F
authors.lastname: Rupp
authors.forename: Hans P
authors.initials: HP
authors.lastname: Wendel
authors.forename: Shila
authors.initials: S
authors.lastname: Sathe
authors.forename: Jürgen
authors.initials: J
authors.lastname: Geis-Gerstorfer
mesh_terms: D000880:Anthraquinones; D002448:Cell Adhesion / Q000502:physiology*; D020099:Coated Materials, Biocompatible; D003746:Dental Enamel Proteins / Q000378:metabolism; D015921:Dental Implants; D044622:Dental Pellicle / Q000502:physiology*; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism*; D006801:Humans; D015603:Keratinocytes / Q000502:physiology*; D010974:Platelet Aggregation / Q000502:physiology*; D011485:Protein Binding; D012821:Silanes; D013499:Surface Properties; D014025:Titanium; D014466:Ultraviolet Rays
chemical_list: D000880:Anthraquinones; D020099:Coated Materials, Biocompatible; D003746:Dental Enamel Proteins; D015921:Dental Implants; D016326:Extracellular Matrix Proteins; D005353:Fibronectins; D012821:Silanes; D014025:Titanium