Enhanced Interfacial Adhesion and Osteogenesis for Rapid "bone-like" Biomineralization by PECVD-Based Silicon Oxynitride Overlays

Azhar Ilyas, Nickolay V. Lavrik, Harry K W Kim, Pranesh B. Aswath, Venu G. Varanasi

Research output: Contribution to journalArticle

16 Scopus citations


Structurally unstable fracture sites require metal fixative devices, which have long healing times due to their lack of osteoinductivity. Bioactive glass coatings lack in interfacial bonding, delaminate, and have reduced bioactivity due to the high temperatures used for their fabrication. Here, we test the hypothesis that low-temperature PECVD amorphous silica can enhance adhesion to the underlying metal surface and that N incorporation enhances osteogenesis and rapid biomineralization. A model Ti/TiO<inf>2</inf>-SiO<inf>x</inf> interface was formed by first depositing Ti onto Si wafers, followed by surface patterning, thermal annealing to form TiO<inf>2</inf>, and depositing SiO<inf>x</inf>/Si(ON)<inf>x</inf> overlays. TEM micrographs showed conformal SiO<inf>x</inf> layers on Ti/TiO<inf>2</inf> overlays while XPS data revealed the formation of an elemental Ti-O-Si interface. Nanoscratch testing verified strong SiO<inf>x</inf> bonding with the underlying TiO<inf>2</inf> layers. In vitro studies showed that the surface properties changed significantly to reveal the formation of hydroxycarbonate apatite within 6 h, and Si(ON)<inf>x</inf> surface chemistry induced osteogenic gene expression of human periosteal cells and led to a rapid "bone-like" biomineral formation within 4 weeks. XANES data revealed that the incorporation of N increased the surface HA bioactivity by increasing the carbonate to phosphate ratio. In conclusion, silicon oxynitride overlays on bone-implant systems enhance osteogenesis and biomineralization via surface nitrogen incorporation.

Original languageEnglish (US)
Pages (from-to)15368-15379
Number of pages12
JournalACS Applied Materials and Interfaces
Issue number28
Publication statusPublished - Jul 22 2015



  • gene expression
  • hydroxyapatite
  • lithography
  • periosteal cells
  • qPCR

ASJC Scopus subject areas

  • Materials Science(all)

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