title: [In vivo experimental study on antibacterial and osteogenic capabilities of hydroxyapatite antimicrobial coating with silver].
abstract: OBJECTIVE
  To investigate the antibacterial and osteogenic capabilities in vivo of hydroxyapatite (HA)/silver (Ag) coating.
  
  
  METHODS
  HA/Ag coating (Ag quality percentage was 3%) and HA coating were deposited to external fixator Schanz screws. The tibial fracture model was established in right hindlimb of 18 adult male Beagle dogs (weighing 15-20 kg). The tibia was stabilized with an external fixator and 2 Schanz screws of HA coating at proximal tibia (control group, n = 18) and HA/Ag coating at distal tibia (experimental group, n = 18), and every screw incision was infected with Staphylococcus aureus. Infection in screw holes and the changes of bone-screw interface were observed by wound grading and X-ray films.
  
  
  RESULTS
  In control group, wounds infection became worse with time (chi2 = 13.492, P = 0.001), while in experimental group, no obvious change was observed chi2X = 0.208, P = 0.901). The wound grading of experimental group was significantly better than that of the control group at 1, 2, and 3 weeks (P < 0.05). Laser scanning confocal microscope showed that there was bacterial adhesion on the surface of screws in 2 groups, viable bacteria mainly in control group and non-viable bacteria mainly in experimental group. The scanning electron microscope (SEM) observation results of the fractured sclerous tissue section showed that an obvious transparent boundary between screw and bone in control group, but no obvious boundary in experimental group. The osseointegration ratios were 76.23% +/- 15.54% in control group and 93.42% +/- 5.53% in experimental group, showing significant difference ( t = 8.843, P = 0.000). The SEM observation showed that HA/Ag coating integrated with new bone and the surface of implant was filled with new bone in experimental group; obvious interspace was seen between the HA coating and new bone in control group.
  
  
  CONCLUSIONS
  HA/Ag coating has good antibacterial and osteogenic capabilities, so it can take effects in preventing infection in screw holes and loosening of implants.
authors: Department of Orthopedics, Sixth People's Hospital, Shanghai Jiaotong University, Shanghai 200233, PR China.
authors: Hongjiang
authors: H
authors: Ruan
authors: Cunyi
authors: C
authors: Fan
authors: Shenghe
authors: S
authors: Liu
authors: Xuebin
authors: X
authors: Zheng
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001863:Bone Screws; D004285:Dogs; D004337:Drug Carriers; D017886:Durapatite / Q000494:pharmacology*; D016267:External Fixators; D008297:Male; D008422:Materials Testing; D010012:Osteogenesis / Q000187:drug effects*; D018030:Silver Compounds / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D004337:Drug Carriers; D018030:Silver Compounds; D017886:Durapatite