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.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Condensed Matter Physics
- Materials Chemistry