Microstructure evolution in Stöber-type silica nanoparticles and their in vitro apatite deposition

Song Chen, Akiyoshi Osaka, Satoshi Hayakawa, Kanji Tsuru, Eiji Fujii, Koji Kawabata

Research output: Contribution to journalArticlepeer-review

39 Citations (Scopus)


Prepared via Stöber-type sol-gel routes were three types of silica particles of <1 μm in size: pure silica, Ca-involving silica, and chitosan/alginate-coated silica with a polymershell-silica core structure. Calcium ions were impregnated in the organic layers of the polymer-coated silica particle. The sol-gel procedure was applied to tetraethoxysilane dissolved in an ethanol/water mixture, while Ca-silica was derived from CaCl 2-containing ethanol/water solutions. Scanning and transmission electron micrograph analyses indicated that those silica particles consisted of ~10 nm primary particles, the Ca-silica particles (~500 nm) were larger than the Ca-free ones (~200 nm) and that their size increased with the Ca concentration in the precursor solutions. From 1H- and 29Si- magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectra and 29Si cross-polarization NMR spectra, the mechanism of primary particle agglomeration and degradation of the secondary particles in saline were discussed in terms of the content of H2O molecules and >Si-OH as well as hydrogen bonding interactions among them. In addition, the Ca-silica and core-shell silica deposited apatite in Kokubo's simulated body fluid. Thus, the present Ca-silica and polymer-coated silica particles were suggested to be applicable to injectable bone fillers for bone generation.

Original languageEnglish
Pages (from-to)322-335
Number of pages14
JournalJournal of Sol-Gel Science and Technology
Issue number3
Publication statusPublished - Dec 2008


  • Apatite
  • Degradation
  • H and Si MAS NMR
  • Microstructure
  • Particles
  • Polymer-coating
  • SBF
  • Silica

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • General Chemistry
  • Biomaterials
  • Condensed Matter Physics
  • Materials Chemistry


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