IADR Abstract Archives
Silicon Oxynitrophosphide Enhances Osteogenesis and Angiogenesis for Rapid Bone Healing
Objectives: Bone defects face delayed healing due to slow re-vascularization and biomineralization. Yet, metal implants used to treat these defects induce slow healing and lack covalent bonding to regenerated bone. Thus, there is a critical need for novel materials that can enhance regeneration and bonding of newly formed bone to implant surfaces. Here, we hypothesize that silicon oxynitrophosphide (Si-O-N-P) overlays on metal implants can enhance bone defect healing through enhanced osteogenesis, angiogenesis, and covalent bonding with surrounding bone.
Methods: Si-O-N-P overlays were nanofabricated onto implant metal surfaces by chemical vapor deposition. Overlay chemistry was characterized by ellipsometry, reflectometry, and x-ray absorbance near edge structure (XANES) spectroscopy. Primary osteoblast and endothelial cell growth and gene expression on Si-O-N-P surfaces were assayed using cell proliferation assay and quantitative polymerase chain reaction, respectively. Rat critical sized cranial defects were used for in-vivo evaluation of Si-O-N-P coated implants vs bare implants for bone and vascular regeneration. Micro-computed tomography (microCT), Raman spectroscopy, scanning electron microscopy (SEM) and histology were used to evaluate biomineral and vascular tubule formation, respectively.
Results: Ca- and P-K-edge XANES analysis showed early formation of hydroxyapatite on Si-O-N-P overlays within 6 hours of in-vitro immersion. In vitro cell culture studies showed enhanced osteogenic marker expression (osterix, 4-fold; osteocalcin, 2.5-fold) and endothelial cell growth (2.6 fold, 5 days) and tubule thickness (2.5-fold, 6-24 hours) vs control surfaces. Raman Spectroscopy, XANES analysis, micro-CT, and histological analysis showed in-vivo tested Si-O-N-P coated implants had fully mineralized and vascularized bone, covalent bonding and > 50% bony contact with surround bone within 5 weeks while bare implants showed no healing.
Conclusions: Si-O-N-P overlays adhere well with metal implant and enhance biomineral and vascular regeneration, thus illustrating their potential to accelerate bone defect healing as an implant coating.
Methods: Si-O-N-P overlays were nanofabricated onto implant metal surfaces by chemical vapor deposition. Overlay chemistry was characterized by ellipsometry, reflectometry, and x-ray absorbance near edge structure (XANES) spectroscopy. Primary osteoblast and endothelial cell growth and gene expression on Si-O-N-P surfaces were assayed using cell proliferation assay and quantitative polymerase chain reaction, respectively. Rat critical sized cranial defects were used for in-vivo evaluation of Si-O-N-P coated implants vs bare implants for bone and vascular regeneration. Micro-computed tomography (microCT), Raman spectroscopy, scanning electron microscopy (SEM) and histology were used to evaluate biomineral and vascular tubule formation, respectively.
Results: Ca- and P-K-edge XANES analysis showed early formation of hydroxyapatite on Si-O-N-P overlays within 6 hours of in-vitro immersion. In vitro cell culture studies showed enhanced osteogenic marker expression (osterix, 4-fold; osteocalcin, 2.5-fold) and endothelial cell growth (2.6 fold, 5 days) and tubule thickness (2.5-fold, 6-24 hours) vs control surfaces. Raman Spectroscopy, XANES analysis, micro-CT, and histological analysis showed in-vivo tested Si-O-N-P coated implants had fully mineralized and vascularized bone, covalent bonding and > 50% bony contact with surround bone within 5 weeks while bare implants showed no healing.
Conclusions: Si-O-N-P overlays adhere well with metal implant and enhance biomineral and vascular regeneration, thus illustrating their potential to accelerate bone defect healing as an implant coating.