【作者】 赵巍；

【导师】 侯振德；

【作者基本信息】 天津大学 ， 工程力学， 2008， 硕士

【摘要】 羟基磷灰石是一种被广泛研究的骨替代材料,由于具有良好的生物相容性、无毒性、生物活性及骨传导性,以及具有与正常骨组织相似的多孔结构和成份,被认为是较理想的骨移植替代材料。将人工制备的羟基磷灰石植入体内除了要考虑它的生物性能还要考虑它的力学性能。当羟基磷灰石被植入人体后伴随着被人体降解和吸收,骨组织在其内部生长,它的强度、刚度逐渐增加,最终成为活体骨的一部分。如果最终能与周围骨组织的力学性质一致,则会与活体骨起到相同的力学作用,可以称为力学相容性。否则会引起负作用,若最终的刚度大于活体骨的刚度则会引起应力遮挡骨吸收,造成周围骨组织的骨质疏松;若刚度太小则起不到承载作用。为研究羟基磷灰石骨替代材料静态力学相容性,本文采用数字图像相关方法研究了用水热交换法制成的羟基磷灰石骨替代材料静态力学性质,这种羟基磷灰石孔隙度比较适合于骨细胞生长。得到了羟基磷灰石完整的应力-应变曲线;在测量弹性模量的同时也得到了泊松比,还测量了压缩极限应力。同时还测量了无有机成份的骨和含有机成份的骨的静态力学性质。测试结果显示羟基磷灰石的静态表观弹性模量平均值为10.91±0.89GPa;泊松比为0.244±0.025,极限应力平均值为14.04±2.01MPa;无有机成份骨的静态弹性模量平均值为12.66±1.78GPa,泊松比为0.132±0.033。极限应力平均值为42.33±2.43MPa;含有机成份骨的静态弹性模量平均值为20.35±1.58GPa,泊松比为0.222±0.035,极限应力平均值为207.06±7.14MPa。为了模拟羟基磷灰石植入体内力学性质变化,在羟基磷灰石表面培养骨细胞10天;将羟基磷灰石植入大白鼠的皮下(与骨组织和软组织接触)经20、40、60天取出,然后测量静态力学性质。发现骨细胞和纤维组织均能使羟基磷灰石材料的弹性模量和强度增加。更多还原

【Abstract】 Hydroxyapatite (HA), as a bone substitutes, has been becoming one of the research focuses of biomaterials, for its good biocompatibility, avirulence, biological activity and osteo-conductivity. Its content and porous structure is similar to bone, so it is considered as ideal bone substitute.If the artificial hydroxyapatite were implanted into body it should either have biocompatibility or mechanical compatibility. After the substitute are implanted into body, on one hand it will be absorption and biodegradation by body , on the other hand bone tissue grow in it, its strength and rigidity increases. Then it becomes a part of bone in vivo. If mechanical properties of the substitute materials consists with surrounding bone, it will has the same mechanical function as bone, which is so called mechanical compatibility. Otherwise, negative results will occur. For example, if the rigidity of implanted materials is bigger than bone, stress shield phenomena will happen and cause osteoporosis. Contrary, if the rigidity of it is smaller than bone, it will not bear loading as bone does.The mechanical properties of hydroxyaptite were tested by digital image correlation technique(DIC),in order to investigate the static mechanical compatibility of hydroxyapatite. The material-hydroxyapatite tested is made by hydrothermal exchange based on natural coral, for its porosity is proper to bone cell grown in. The stress-strain curves of the hydroxyapatite was obtained. Both Young’s modulus and Poisson’s ratio can be obtained. Bone with and without organic components were also tested by DIC. The results show that the apparent Young’s moduli of HA, bone with and without organic component are 10.91±0.89 GPa, 20.35±1.58 GPa and 12.66±1.78 GPa respectively. The average ultimate stress are 14.02±2.01MPa, 207.06±7.14MPa and 42.33±2.43MPa respectively. The Poisson’s ratio are 0.244±0.025, 0.222±0.035, 0.132±0.033. In order to simulate the condition of HA in vivo, the osteoblastic have been cultured on HA for 10 days and HA have been implanted in rat subcutaneous for 20, 40, 60days. The mechanical properties of HA were also tested by DIC.The results show that osteoblast and subcutaneous tissues can increase Young’s modului and compressive strength of hydroxyaptite.更多还原