title: Bone response to the multilayer BMP-2 gene coated porous titanium implant surface.
abstract: OBJECTIVE
  Evaluate hBMP-2 expression following gene delivery from plasmid multilayers formed on sandblasted titanium in vitro and bone formation around similarly prepared implant surfaces in vivo.
  
  
  METHODS
  Multilayers of cationic lipid/rhBMP-2 plasmid DNA complex (LDc) and anionic hyaluronic acid (HA) was assembled on sandblasted-dual acid etched pure titanium disks or implant surfaces using layer-by-layer (LBL) assembly. Gene delivery and hBMP-2 expression in cells exposed to the LDc multilayers was measured in vitro. To determine the effect of BMP delivery from such multilyaers in vivo, roughened implants coated with BMP-2 LDc multilayers or uncoated control implants (n = 15 for both) were implanted in the femurs of NZW rabbits. After 2, 4, 8 weeks, femurs were retrieved and prepared for histomorphometric evaluation (n = 5 rabbits per time point).
  
  
  RESULTS
  MC3T3-E1 cells cultured directly on the BMP-2 LDc coated titanium disks showed EGFP and hBMP-2 expression after 48 h in culture. Increased gene delivery occurred by increasing the number of assembly layers when cells were cultured for 48 h. Cells cultured on LDc coated surfaces had significantly higher cell viability than control cells cultured on uncoated porous titanium surfaces. Histologic observation of the implants showed that after 4 weeks healing, the bone to implant contact (BIC) on the LDc coated surface was much lower than that on the control surface, but didn't reach significant. In contrast, the percentage of bone within the implant's threads was significantly higher than the control group (P = 0.047).
  
  
  CONCLUSIONS
  The BMP-2 gene coated sandblasted dual acid etched titanium implants slightly accelerated early bone formation around implants.
authors.affiliation: Department of Oral Implantology, The Affiliated Stomatology Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Qiao-Hong
authors.initials: QH
authors.lastname: Jiang
authors.forename: Li
authors.initials: L
authors.lastname: Liu
authors.forename: Sean
authors.initials: S
authors.lastname: Peel
authors.forename: Guo-Li
authors.initials: GL
authors.lastname: Yang
authors.forename: Shi-Fang
authors.initials: SF
authors.lastname: Zhao
authors.forename: Fu-Ming
authors.initials: FM
authors.lastname: He
mesh_terms: D016475:3T3 Cells; D000134:Acid Etching, Dental / Q000379:methods; D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000235:genetics / Q000494:pharmacology*; D018929:Cell Culture Techniques; D002470:Cell Survival / Q000187:drug effects; D020099:Coated Materials, Biocompatible / Q000494:pharmacology*; D045662:Dental Etching / Q000379:methods; D015921:Dental Implants; D003764:Dental Materials / Q000737:chemistry*; D005269:Femur / Q000187:drug effects*; D005456:Fluorescent Dyes; D049452:Green Fluorescent Proteins; D008055:Lipids; D008081:Liposomes; D051379:Mice; D016348:Osseointegration / Q000187:drug effects; D010006:Osteoblasts / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects* / Q000502:physiology; D010957:Plasmids / Q000235:genetics; D016062:Porosity; D011817:Rabbits; D011994:Recombinant Proteins / Q000235:genetics / Q000494:pharmacology; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*; D014162:Transfection / Q000379:methods; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000494:pharmacology*
chemical_list: D055396:Bone Morphogenetic Protein 2; D020099:Coated Materials, Biocompatible; D015921:Dental Implants; D003764:Dental Materials; D005456:Fluorescent Dyes; D008055:Lipids; C086724:Lipofectamine; D008081:Liposomes; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C485184:enhanced green fluorescent protein; C499469:recombinant human bone morphogenetic protein-2; D049452:Green Fluorescent Proteins; D014025:Titanium