热压-盐析法制备骨组织工程支架的工艺及性能表征米

背景:热压-盐析法制备聚合物组织工程支架,设备简单,成型快速,力学强度较高,但是适当的支架成型条件及材料组分对支架的性能尤为重要.目的:观察热压-盐析法制备聚乳酸/聚己内酯/纳米羟基磷灰石复合组织工程支架中温度、时间、压力以及羟基磷灰石的加入对支架性能的影响.设计、时间及地点:复合材料性能测试,对比观察实验,于2008-09/2009-05在同济大学材料科学与工程学院纳米与生物高分子材料研究所完成.材料:聚乳酸、聚己内酯、羟基磷灰石均为实验室合成.方法:采用液相共沉淀法制备纳米羟基磷灰石,借助溶剂将聚乳酸、聚己内酯、纳米羟基磷灰石和致孔剂进行共混,去除溶剂后在一定温度、压力、时间下进行热压制得聚乳酸/聚己内酯/纳米羟基磷灰石复合组织工程支架.主要观察指标:①X射线衍射分析、透射电镜观察羟基磷灰石的相结构、形状和尺寸.②扫描电镜观察复合多孔支架的形貌.⑧通过表面接触角观察不同材料的亲水性.④不同热压时间、温度、压力对支架孔隙率及抗压强度的影响.⑤不同含量羟基磷灰石对支架抗压强度的影响.结果:热压-盐析法制备的聚乳酸/聚己内酯/纳米羟基磷灰石复合组织工程支架具有连通开孔的多孔结构,孔径多分布在300～340 μm,支架的表面无结皮现象,孔隙率和抗压强度均满足骨支架的应用要求;纳米羟基磷灰石的加入提高了支架的抗压强度,但支架亲水性随其质量分数的升高而下降,纳米羟基磷灰石质量分数为4%时支架的综合性能相对较好;热压温度、时间、压力对支架的性能影响较大,支架的综合性能在热压温度65℃、热压压力7 MPa、热压时间3 min条件时相对较好.结论:热压-盐析法构建的骨组织工程支架孔径、孔隙率和抗压强度均满足应用要求;热压温度、时间、压力对支架的性能影响较大;纳米羟基磷灰石的加入提高了支架的抗压强度,但对支架亲水性有影响.

Technology and characterization of bone tissue engineering scaffold using hot-pressing and particulates leaching process

BACKGROUND: Hot-pressing and particulates-leaching is a convenient method to construct bone tissue engineering scaffold and the properties of the constructed scaffold are well. Both process and materials have effect on the properties of the constructed scaffold. OBJECTIVE: To investigate the influence of content of hydroxyapatite (HA), time, temperature and pressure of the hot-pressing on the properties of the scaffold.DESIGH, TIME AND SETTING: A bone tissue engineering scaffold construction experiment was performed at Institute of Nano and Bio-Polymeric Materials, School of Material Science and Engineering, Tongji University from September 2008 to May 2009. MATERIALS: Polylactic acid (PLA), polycaprolactam (PCL) and HA were synthesised in our laboratory. METHODS: The PLA/PCL/nHA bone tissue engineering scaffold was fabricated via hot-pressing and particulates leaching. Briefly, the PLA and PCL with weight ratio of 7:3 were dissolved into chloroform to form polymer solution. nHA was dispersed into the polymer solution after ultrasonic vibration. Then, sodium chloride was added into the solution to obtain a composite. After the chloroform was removed by evaporation and vacuum-dried, the composite were charged into a mold. MAIN OUTCOME MEASURES: ①The phase, shape and size of HA was investigated by XRD and transmission electron microscope.②Morphology of scaffold was investigated by scanning electron microscope. ③Hydrophilicity was investigated by surface contact angle. ④Influence of hot-pressing time, temperature and pressure on the porosity and compressive strength of the scaffold. ⑤Influence of different content of HA on the compressive strength and surface contact angle of scaffold. RESULTS: The result showed that the pores of PLA/PCL/nHA scaffold were in diameter of 300-340 urn and interconnected. The surface of the scaffold was also interconnected pores, but not the structure like "skin". The porosity and compressive strength met the requirements of the application of the scaffold. The compressive strength of the scaffold contained HA increased while the water absorption decreased. The properties of the scaffold were much better when the content of the HA was 4%. Moreover, the time, temperature and pressure also affected the properties of the scaffold. The result showed that the properties of scaffold was much better when it was fabricated under holding the pressure of 7 MPa at 65℃ for 3 minutes. CONCLUSION: The bone tissue engineering scaffold constructed by hot-pressing and particulates-leaching can meet the needs of the application. The hot-pressing temperature, time and pressure do have effect on the properties of the scaffold. HA can enhance the compressive strength of the scaffold; moreover, it decreases the hydrophilicity of the scaffold.