磷酸钙陶瓷在不同动物的模拟体液中类骨磷灰石的形成研究

Bone-like Apatite Formation on Calcium Phosphate Ceramics in Different Kinds of Animal Simulated Body Fluid

根据人、狗、猪、猴和兔五种动物体液的钙离子浓度和pH值的差异,配制了不同组分的模拟体液,将孔壁致密和有微孔的多孔磷酸钙陶瓷分别浸泡在这些模拟体液中,研究陶瓷孔隙表面类骨磷灰石的形成情况.结果表明:在模拟体液中浸泡14天后,孔壁致密的材料未见有类骨磷灰石层形成;有微孔的多孔磷酸钙陶瓷,材料孔壁表面(包括陶瓷表面较深孔隙)有类骨磷灰石层的形成,这与体内植入实验观察到的类骨磷灰石层形成和诱导成骨情况相似,可以推论类骨磷灰石层的形成的确是骨诱导的先决条件.随着钙离子浓度的增加,其孔壁表面类骨磷灰石层的形成也更为均匀,但类骨磷灰石生长快慢顺序与动物组织学观察到的骨诱导性高低的次序不完全一致.

Five kinds of simulated body fluid (SBF) were prepared according to the Ca2+ ions concentration in body fluids of human, dog, pig, rabbit and monkey. The cylindrical porous specimens of phi4x8mm were obtained by sintering the green block of biphasic calcium phosphate(HA/TCP=70/30) at 1200degreesC. There were two kinds of porous specimens: dense pore wall and pore wall with micro pores. After 14-day immersion in SBF, bone-like apatite formed on the pore wall with micro pores while no apatite was observed on the smooth pore wall. The bone-like apatite grew faster in SBF of dog and rabbit than in other SBF. In animal experiment, the same phenomena were also observed: bone-like apatite formed faster on specimens implanted in dog and rabbit than in other animals. This sequence is different from the order of osteoinductivity of biphasic calcium phosphate ceramics implanted in these animals. The results show the formation of bone-like apatite on materials is an important factor but not the only factor for their osteoinduction.