义眼台用羟基磷灰石的制备和性能

Preparation and properties of porous hydroxyapatite for orbital implants

采用均相共沉淀法直接合成了高纯度羟基磷灰石粉体,通过改变反应物加入方式和反应时间调控粉体形貌和组成,分析了体系pH值对产物纯度的影响;以硅溶胶为粘结剂、尿素为造孔剂,室温下压制成型,高温烧结制备了孔隙度高、力学性能良好的多孔羟基磷灰石块体,考察了粉体粒径、造孔剂含量对孔隙度和抗压强度等性能的影响。结果表明,纳米粉有利于块体成型,随造孔剂含量增加,块体密度减小、孔隙度增加,当羟基磷灰石与尿素质量比为1.5:1时,孔隙度达69%,抗压强度达8MPa,满足义眼台应用需求。

The bio-eye porous hydroxyapatite(HAP)orbital implants are attracting considerable attention for the requirement of anophthalmusreconstruction.It is crucial to have the highly interconnected porous structure including appropriate macropores and micropores for improving the penetration and ingrowth of vascular orbital tissues.However,the mechanical strength of HAP to maintain the natural lid shape and prevent damage over time will decrease with the porosity increasing.Addressing this challenge,HAP with good mechanical performance for orbital implants were designed and prepared through a simpleprocess.Hydroxyapatite powders with different particle sizes were synthesized by homogeneous precipitation method using commercially available calcium salt and phosphate salt as raw materials.The effects of addition method of reactants and pH value of system on morphology and composition of HAP powders were investigated.HAP powders werecharacterized by SEM,TEM,XRD,Raman spectrum and FT-IR.Uniform porous hydroxyapatite bulks weresintered at 1000℃ and fabricated using urea as pore generator and silica solas binder.Detailed studies were performed to evaluate its structure,porosities,and mechanical properties,emphasizing the effect of different particles size of HAPand feeding content of urea.The results showed that the HAP microspheres with a diameter of 39~154μm and rod-shaped HAP powders with a diameter of 10~15 nm and a length of 24~36 nm were prepared.The as-preparedsamples were hexagonal hydroxyapatite and had good crystallinity,due to the abundantphosphate and hydroxyl groups on the surface of powders,good biocompatibility can be expected.Nano-sized powders was helpful to the formation of porous bulks and the porosity was controlled by adjusting the amount of urea.The apparent porosity up to 69% and compressive strength reached8 MPa when the massratio of HAP to urea was 1.5:1.