The purpose of this study is to explore the osteoinductivity of the composite materials (calcium
phosphate ceramics/PLA or collagen composites) with similar physical character of osteoinductive
calcium phosphate ceramics and the influence of the chemical composition of the composite materials on
osteoinductivity, and also to provide an experimental evidence for optimizing the design of the composite
materials. Two kinds of composite materials were prepared. One (BCP/PLA) is fabricated with different
ratio of BCP (biphasic calcium phosphate) ceramics powder and PDLLA powder through the particulateleaching
technique. The other (BCP/collagen) is that BCP ceramics sintered at 1250oC and modified with
collagen. The porous materials cylinders with Φ 5×8 mm were prepared. SEM was used to observe the
microstructure and physical morphology of the composite materials. The two groups of composite
materials cylinders were implanted in the dorsal muscles of four dogs. Six samples of each group were
implanted in each dog respectively. The specimens were harvested at 2, 4, 12 and 24 weeks post operation,
and thin decalcified sections were prepared for light microscopy (LM) analysis to evaluate their
osteoinductivity and compare the capability of osteoinduction. The fibro-tissue and bone-like tissue were
observed in the two composites, but no obvious bone formation was found in the tested periods. The
results indicated that the composite materials could modify the mechanical property of ceramics.
However, if the composite materials were biodegraded soon, new bone could not form into the scaffold,
and the calcium phosphate should be the major component of osteoinductive materials.
VEGF incorporated into calcium phosphate ceramics promotes vascularisation and bone formation in vivo
