摘要
目的:利用显微CT的成像技术及材料力学测试,观察多孔双相磷酸钙陶瓷支架的三维结构和力学仿生性能特征。方法:实验于2004-06/2005-12在清华大学新型陶瓷与精细工艺国家重点实验室、香港中文大学威尔士亲王医院骨与关节肌肉研究室和解放军总医院骨科研究所完成。利用三维凝胶叠层成型技术和发泡法复合的方法,制备仿骨多孔双相磷酸钙陶瓷支架,经显微CT扫描得到分辨率为20μm的断层图像,并按骨形态计量方法计算三维计量参数,并与急性脑死亡年轻人股骨头(由解放军总医院骨组织库提供,已签署捐献同意书)标本负重区松质骨样本的三维参数进行统计比较。最后对双相磷酸钙陶瓷支架两个互相垂直方向和松质骨样本的长轴方向进行压缩强度试验,计算压缩强度和弹性模量,并进行统计分析。结果:①双相磷酸钙陶瓷支架的小梁平均宽度和间距低于松质骨小梁(P<0.05);支架的小梁数目和各项异性程度高于松质骨样本(P<0.05);说明支架小梁在排列上呈现更为明显的各向异性特征。②双相磷酸钙陶瓷支架的体积分数、表面积体积比及结构模型指数与松质骨样本相比差异无显著性(P>0.05),两组样本均呈明显的板层结构。③力学测试结果显示双相磷酸钙陶瓷支架材料长轴方向的强度和弹性模量高于垂直方向(P<0.05),说明支架材料具有明显的方向性。长轴方向的强度低于正常松质骨样本,但弹性模量仅比松质骨样本弹性模量高20%(P<0.05)。结论:支架材料在空隙率和表面积方面具有很好的仿生性,利于细胞的黏附和长入。同时具有明显的方向性,提高了其在排列方向上的强度。弹性模量接近股骨头松质骨,具有较好的应力顺应性。
AIM： To evaluate the three-dimensional （3D） microarchitectural and mechanical biomimetic characteristics of porous biophasic calcium phosphate （BCP） ceramic scaffold with micro CT imaging and mechanical testing.
METHODS： The experiment was carried out at the state key laboratory of new ceramic and fine processing of Tsinghua University, the Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong and the Orthopaedic Institute of General Hospital of Chinese PLA between June 2004 and December 2005. Biomimetic BCP scaffolds were fabricated with 3D gel-lamination technique and foaming methods. Then these BCP scaffolds were scanned using a desktop MicroCT system with an isotropic voxel dimension of 20 μm. 3D structural parameters were calculated using built-in software. So was done with the cancellous bone samples harvested from the Ioad-beanng region of femoral head （provided by osseous tissue bank of General Hospital of Chinese PLA, and the donation consent was signed） of youth with acute brain death. Finally, compression tests were applied on both the BCP scaffolds from two directions-along the axis and vertical to the axis, and the cancellous bone samples. Compressive strength and elastic modulus were calculated. Statistical analysis was performed on these structural and mechanical data.
RESULTS： （1）The mean trabecular plate thickness （Tb.Th） and trabecular separation （Tb.Sp） of the scaffolds＇ struts were less than those of the cancellous bone （P 〈 0.05）. The trabecular number （Tb.N） and degree of anisotropy （DA） of the scaffolds were more than those of the bone samples （P 〈 0.05）. It indicated that the trabecular scaffold showed more obviously anisotropic feature. （2）Whereas, no significant difference was demonstrated in bone volume fraction （BV/TV）, bone surface/bone volume ratio （BS/BV） and structure model index （SMI） （P 〉 0.05） between the scaffolds and the cancellous bone samples. Both groups of samples represented an obvious plate-like model. （3）The mechanical test showed that the average compressive modulus and ultimate strength along the axis of the scaffolds were larger than those vertical to the axis （P 〈 0.05） which demonstrated the oriented feature of scaffolds. Although the ultimate strength along the axis of the scaffolds was lower than that of bone samples, but the modulus was only 20% higher than that of the bone samples （P 〈 0.05）.
CONCLUSION： The BCP scaffolds have good mimetic properties in porosity and surface area that was advantageous to cell attachment and ingrowth. The oriented feature of the scaffolds improved the strength along the struts array and the modulus was close to normal trabecular bone that demonstrated a good biomechanical compatibility.
出处
《中国组织工程研究与临床康复》
CAS
CSCD
北大核心
2007年第9期1636-1639,共4页
Journal of Clinical Rehabilitative Tissue Engineering Research
基金
国家自然科学基金重点课题资助(30330570)~~
