Preparation And Properties Of Cellular Porous Calcium Phosphate Bone

Concerning continuous forming, high efficiency, uniform and controllable pore size and high porosity, the extrusion molding was widely used to fabricate porous ceramics. Bone scaffold with honeycomb structure was prepared by the method of extrusion molding with hydroxyapatite and monetite whisker as raw materials and mesopores on pore wall was obtained by the addition of PMMA microspheres porogen before extrusion.The mixture of HAP/CaHPO4 whisker and hydrosol of KGM can be suitable for extrusion because the hydrosol of KGM showed good rheology; A mold core suited for injection of extrusion was designed by the laser processing of perspex plate, so scaffold with honeycomb tunnels (<600μm) can be shaped one-time, which avoids the subsequent step of adjusting tunnels by means of slip-casting. Biological ceramics showed decreasing of bioactivity and biodegradability, which is caused by the abnormal grain grouth and dense structure in high temperature sintering, thus it was expected to improve the biological properties through heat treatment at low temperature.Porous body was soaked in silica sol for 0.5h after heat treatment at 550℃ for 2h, then BCP/SiO2 bone scaffold was fabricated. The bone scaffold exhibited macropore with uniform pore size of 400-600μm, the porosity and compressive strength was about 69.04% and 1.17Mpa, respectivity. In addition, the cell proliferation is above 100% when concentration of porous material extracts is less than 0.12g/ml, which showed promoting cell proliferation.On the basis of previous study, in order to improve the porosity of the pore wall’ mesopores, the PMMA microspheres (D50 is about 180μm) as porogen was introduced to the raw materials for extrusion. Green body underwent heat treatment of 800℃ for 2h and was soaked in silica sol for 0.5h. The composition of porous body was β-TCP/(3-Ca2P2O7 and amorphous SiO2 as binder. When the amount of PMMA microspheres was 30%, the porosity bone scaffold was increased from 69% to 80%, the tunnels formed by extrusion was about 350-550μm, pore wall’mesopores size of 180-220μm and micropores caused by the thermolysis of KGM were approximately 2μm, but the compressive strength was decreased from 1.17Mpa to 0.66Mpa approximately. Moreover, Bone scaffold had a role in promoting cell proliferation when concentration of porous material extracts is less than 0.1g/ml and cytotoxicity was qualified below 0.2/ml.