Bioactive Aerogel Bone Graft Substitutes

Example 4

FIG. 1 shows the N₂ adsorption isotherm of sample 2.

Bioactivity testing (ability to precipitate hydroxyapatite) was carried out on sample 2 using a simulated body fluid test.

FIG. 2 shows the absorbance spectra after 3 hours of immersion in simulated body fluid. The precipitation of hydroxyapatite is confirmed by the presence of two bands at 560 and 600 cm⁻¹.

This is an industry standard test to demonstrate that a material is bioactive. This test is widely accepted to demonstrate that a material which is bioactive in simulated body fluid would, once in the body, be able to form bone on its surface. This is an essential property for bone substitute materials.

FIGS. 3 and 4 show a scanning electron micrograph of sample 2 after calcination.

The structure of the unreacted sample 2 shows silica spheres forming a bioactive aerogel structure.

This data demonstrates that the bone graft substitutes of the present invention are bioactive and exhibit low densities and high surface areas, compared to typically used bones graft substitutes.