title: Progression of osteogenic cell cultures grown on microtopographic titanium coated with calcium phosphate and functionalized with a type I collagen-derived peptide.
abstract: BACKGROUND
  The functionalization of metallic surfaces aims at promoting the cellular response at the biomaterial-tissue interface. This study investigates the effects of the functionalization of titanium (Ti) microtopography with a calcium phosphate (CaP) coating with and without peptide 15 (P-15), a synthetic peptide analog of the cell-binding domain of collagen I, on the in vitro progression of osteogenic cells.
  
  
  METHODS
  Sandblasting and acid etching (SBAE; control) Ti microtopography was coated with CaP, enabling the loading of two concentrations of P-15: 20 or 200 μg/mL. A machined Ti was also examined. Rat calvarial osteogenic cells were cultured on Ti disks with the surfaces mentioned above for periods up to 21 days (n = 180 per group).
  
  
  RESULTS
  CaP coating exhibited a submicron-scale needle-shaped structure. Although all surfaces were hydrophobic at time zero, functionalization increased hydrophilicity at equilibrium. Microtopographies exhibited a lower proportion of well-spread cells at 4 hours of culture and cells with long cytoplasmic extensions at day 3; modified SBAE supported higher cell viability and larger extracellular osteopontin (OPN) accumulation. For SBAE and modified SBAE, real-time polymerase chain reaction showed the following results: 1) lower levels for runt-related transcription factor 2 at 7 days and for bone sialoprotein at days 7 and 10 as well as higher OPN levels at days 7 and 10 compared to machined Ti; and 2) higher alkaline phosphatase levels at day 10 compared to day 7. At 14 and 21 days, modified SBAE supported higher proportions of red-dye-stained areas (calcium content).
  
  
  CONCLUSIONS
  Addition of a CaP coating to SBAE Ti by itself may affect key events of in vitro osteogenesis, ultimately resulting in enhanced matrix mineralization; additional P-15 functionalization has only limited synergistic effects.
authors.affiliation: School of Dentistry of Ribeirão Preto, University of São Paulo, São Paulo, Brazil.
authors.forename: Karina K Y
authors.initials: KK
authors.lastname: Pereira
authors.forename: Olívia C
authors.initials: OC
authors.lastname: Alves
authors.forename: Arthur B
authors.initials: AB
authors.lastname: Novaes
authors.forename: Fabíola S
authors.initials: FS
authors.lastname: de Oliveira
authors.forename: Ji-Hyun
authors.initials: JH
authors.lastname: Yi
authors.forename: Osvaldo
authors.initials: O
authors.lastname: Zaniquelli
authors.forename: Cornelia
authors.initials: C
authors.lastname: Wolf-Brandstetter
authors.forename: Dieter
authors.initials: D
authors.lastname: Scharnweber
authors.forename: Fabio
authors.initials: F
authors.lastname: Variola
authors.forename: Antonio
authors.initials: A
authors.lastname: Nanci
authors.forename: Adalberto L
authors.initials: AL
authors.lastname: Rosa
authors.forename: Paulo T
authors.initials: PT
authors.lastname: de Oliveira
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000469:Alkaline Phosphatase / Q000032:analysis; D000818:Animals; D000831:Animals, Newborn; D002113:Calcification, Physiologic / Q000502:physiology; D002130:Calcium Phosphates / Q000737:chemistry*; D002448:Cell Adhesion / Q000502:physiology; D002452:Cell Count; D018929:Cell Culture Techniques; D002465:Cell Movement / Q000502:physiology; D049109:Cell Proliferation; D002470:Cell Survival / Q000502:physiology; D002478:Cells, Cultured; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D003094:Collagen / Q000737:chemistry*; D050659:Core Binding Factor Alpha 1 Subunit / Q000032:analysis; D003593:Cytoplasm / Q000648:ultrastructure; D045662:Dental Etching / Q000379:methods; D057927:Hydrophobic and Hydrophilic Interactions; D058574:Integrin-Binding Sialoprotein / Q000032:analysis; D010006:Osteoblasts / Q000502:physiology* / Q000648:ultrastructure; D053495:Osteopontin / Q000032:analysis; D010446:Peptide Fragments / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*
chemical_list: D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; D050659:Core Binding Factor Alpha 1 Subunit; C546873:Ibsp protein, rat; D058574:Integrin-Binding Sialoprotein; D010446:Peptide Fragments; C493717:Runx2 protein, rat; C506897:Spp1 protein, rat; C407062:cell-binding peptide P-15; D053495:Osteopontin; D003094:Collagen; C020243:calcium phosphate; D014025:Titanium; D000469:Alkaline Phosphatase